ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION.Reagents and Reuctions.SODAMIDE, which was used by Claisen (AnnuaE Report, 1905, 108) as acondensing agent, has been employed by Semmlerl for breaking downa cyclic ketone wherein a methyl carbon complex adjoins the ketonegroup :*C *C\Q(CH,), + 4 - \(?H(CH,),*NHNa'NHNa. C P 0Thus, fenchone gives the amide of dihydrofencholenic acid ( b ) , whichdiffers from Mahla's acid (a). The following, according to Semmler,represents the relation of fenchone to the acid :CH CH CHFenchon e , Dihydrofencholcnic acid.Sachs2 and his collaborators in a preliminary paper describe theuse of sodamide for preparing aromatic amines from sulphonic acids.A number of naphtholsulphonic acids have been converted into amino-naphthols by fusion of the sodium salt of the sulphonic acid withsodamide,The 1 : 5-, 1 : 8-, and 2 : 7-naphtholsulphonic acids give good yields ofthe corresponding aminonaphthols, whilst the 2 : 6- and 2 : 8-acids form1 : 6-aminonaphthol. As P-naphthol is converted directly into the1 : 6-amino-compounds, the above isomeric change appears to result fromthe rupture of the sulphonic group and the intermediate production ofP-naphthol from the two P-naphthol sulphonic acids :CloH,*ONn + NaNH, = CloK,(ONa)*NHNa i- 33,.The nitro- and halogen derivatives of benzene give poor yields ofBer., 1906, 39, 2577. Ibid., 3006ORGANIC CHEMISTRY-HOMOCYCLIC DIVJSION.115amino-derivatives ; benzene- and naphthalene-sulphonic acids furnish30-50 per cent. of the amino-compounds.A curious result was obtained by fusing together a mixture ofnaphthalene, phenol, and sodamide, when a-naphthylamine and1 : 5-naphthylenediamine were obtained.Sodium bisulphite, which Bucherer has already utilised in variousingenious synthetic processes,1 has now been applied by the same ob-server2 to the preparation of w-sulphonic acids and o-cyanides of aromaticamines. The reaction in question consists in acting on the amine with analdehyde bisulphite and heating the product with potassium cyanide :R*NH, + HO*CHR1*SO,Na = R*NH*CHR,*SO,Na + H20.R*NH*CHR,*SO,Na + KCN = R*NH*cHR,.CN + KNaSO,.Thus, formaldehyde bisulphite and aniline yield sodium methyl-aniline-w-sulphonat e, N HPh*CH,*SO,Na, and w-cyanomet h ylan iline,NHPh.CH,.CN.The importance of this reaction in its connexionwith the indigotin synthesis may be realised from the fact that o-cyano-methylaniline and w-cyanomethylanthranilic acid can be readily obtainedand transformed in to the corresponding acids.The preparation of a-amino-acids, described by Zelinsky andStadnikoff ,3 by the combined action of potassium cyanide, ammoniumchloride, and water on aldehydes, although apparently not new (theprocess was actually patented by Bucherer in 1904), is sufficientlyinteresting t o be reproduced. The changes are explained by thefollowing series of equations :1. KCN + H20 = HCN + KOH.2. R-CHO + HCN = R*CH(OH).CN.3. NH,Cl + KOH = NH, + KC1 + H20.4. PLCH(OH).CN + NH, = R*cH(NH,).CN + H20.Seyewetz and 1610ch4 have employed sodium hyposulphite in presenceof sodium phosphate as reducing agent for nitro-compounds, andobtained the sodium sulphonamates of the base.Nitrobenzene givesan equal weight of the sulphonamate, whilst the yield from nitro-toluene is even better :C,H,*NO, -t Na2H204 + H20 = C,H,*NH*SO,Na + NaHSO,.The action of thiocarbimides on ethylene-aniline and -t,oluidine hasbeen studied by Davis,5 with interesting results. The general characterof the products is represented by the following formulte :$lH9-NR*CS N HR, FH2*NR:CS*NHRC H ~ ~ N H R CH,=NR-CS*NHM,’Ann. &epo?l, 1904, 86.Cow@. rend., 1906, 142, 2052.Be?., 1906, 39, 986, 2796. Ibid., 1722.Trans., 1906, 89, 713,J 116 ANNUAL REPOKTS ON THE PROGRESS OF CHEMISTRY.the union with one or two molecules of thiocarbimide being determinedby the nature of the two reacting substances.The use of copper referred to in a former Report has been furtherextended by Ullmann and Maag 2 to the preparation of y-phenylene-dianthranilic acid, C,H,( NH* C,H,*C0,H)2, from p-dibromobenzene andanthranilic acid dissolved in amyl alcohol in presence of cuprouschloride and finely-divided copper, .which are heated together to140-150".Tbe product is readily condensed to quinacridone,A similar method is described by Goldberg3 for convertinganthranilic into phenylanthranilic acid, &c. Ullm-inn and Stein 4 havealso used copper as a catalytic agent for preparing phenyl et.hers fromphenols arid aromatic bromo-compounds. Bromobenzene and guaiacol,or o-bromoanisole and phenol, with potassium hydroxide and a trace ofcopper, yield o-methoxydiphenyl ether.Francis has shown that benzoyl nitrate, C,H,*CO*O*NO,, obtainedby the action of silver nitrate on benzoyl chloride, may be employedas a useful nitrating agent.Ponzio 6 finds that sodium hypochlorite converts aromatic aldoximesinto diarylglyoxime peroxides of the formula,R*CH:N,O,:CH*R.Minunni and Ciusa 7 use amyl nitrate for the same purpose.On theother hand, the chief product of the action of nitrogen peroxide onbenzaldoxime, which Scholl described as diphenylglyoxime peroxide,is in reality dinitrophenylrnetbarle, C',H,*CH:N,O,. Other aromaticaldoximes give similar products.sA new method of esterification is described by Raikow and T i s c h k o ~ , ~who use syrupy phosphoric acid for effecting the union of alcohol andacid.Gattermanri 10 gives a long and interesting review of the variousmethods which he has introduced into the preparation of aromaticaldehydes.Some of these have already boen described, and include(1) the carbon monoxide method, (2) the hydrogen cyanide methodin presence of cuprous or aluminium chloride. The use of organo-magnesium compounds in conjunction with (3) formic ester and (4)Ann. Beport, 1905, 102.Ibid., 1691. Ibid., 622. Ibid., 3798.Atti 12. Accccd. Sci. To~ino, 1906, 41, 415 ; J. yr. Chcm., 1906, 73, 797.7 Atti K . Accccd. Lincei, 1905, [v], 14 ; ii, 518 ; also Fraiizen and Zimniciniann,. li A t t i 1C. Accad. Lincei, 1906, [v], 15, 118.!' C'hcwi.Zc:t., 1905, 29, 1268.Ber., 1906, 39, 1693.J. pr. C'hc71~. lbO6, 73, 253.lo A?Lnale?i, 1906, 347, 347ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 117ethoxymethyleneaniline is quite new, and the reactions take phceaccording to the following equations :1. CH,*C,H, + ClCHO = CH,'C!6H4*CH0 + HCI.2. CH3*O*C,H, + C1CR:NH = CH,*O*C,H,*CH:NH + HCl.CH,*O*C,H,*CH:NH + H20 = CH,*O*C,H,*CHO + NH3.3. RMgBr + C02H-C,H, = R*CHO + C,H,-OMgBr.4. RMgBr + C,H,O*CH:N*C,H, = R*CH:N*C,H, + C,H,*OMgBr.R*CH:N*C,H, + H20 = R*CHO + C,H,*NH2Lapworth 1 has continued his researches on the addition of hydrogencyanide to unsaturated hydrocarbons (Annual Report, 1904, 104), andhas prepared cyanodihydrocarvone, which on hydrolysis yields twostereoisomeric carboxylic acids exhibiting dynamic isomerism :Cyanodihydrocarvone.Grignard's Reaction.-This protean synthetic reagent still engagesthe attention of chemists; but although many papers have appearedon the subject in the past year, few novel applications have beenbrought to light.Reference may be made to the following: Kohlerand his collaborators have continued their investigations on theaction of alkyl and nryl magnesium bromides on unsaturated com-pounds, and find that the phenyl esters of cinnamic and a-phenyl-cinnamic acid with magnesium phenyl bromide yield, among a varietyof other products, triphenylpropiophenone and tetraphenylpentsnone :CHPh,. CHPh COPh CO(CH,.CHP~I~)~.Triphcnylpropiophenone. Tetraphenylpentnnone.With a/3-unsaturated cyanides,3 additive compounds are formed.Thus, magnesium ethyl bromide and a-phenylcinnamonitrile give twostereoisomeric derivatives according to the equation CHPh:CPh.CN +Et*MgBr + H,O = CHPhEt*cHPh.CN + MgBr*OH.With magnesium phenyl bromide two products are obtained, namely,an unsaturated ketone and a saturated nitrile :C HPh:CPh*CPh:O CHPh,* CHPh* CN.An interesting method for obtaining esters of alcohols and phenols,which depends on Grignard's reagent, is the subject of a patent byH ~ u b e n .~ It consists in treating the anhydride or acid chloride withthe magnesium alkyl halide and the alcohol or phenol. The alcohol isTrans., 1906, 89, 945.Amer. Chcm. J., 1906, 35, 386.'L Kohler and Heritage, Amel.. C'hem. J., 1905, 34, 568.Ber., 1906, 39, 1736.118 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.converted into the halide magnesium alcoholate, which then reacts withthe anhydride :For unsaturated alcohols, magnesium benzyl, methyl, or ethylchloride were found necessary.In this way esters of linalool,terpineol, thymol, borneol, &c., were obtained.It is well known that magnesium alkyl and argl halides unite withcarbon dioxide to form acids.1 Honben2 has shown that carbondioxide can be replaced by carbon disulphide in quite an analogousfashion, forming what the author terms cccrbithionic acids :R*MgX+CS, -+ R*CS,*MgX -+- R*CS,H.They are yellow, red, or violet oils, which are unstable in the freeThey have no tendency to state and have strongly acid properties.form anhydrides, but easily pass into thioacyl disulphides,R*CS* S,*SC *R.To a similar class of reactions belongs the union of sulphur dioxidewith magnesium alkyl halides, which has been investigated by Wuytsand Cosyns,s and also by Houben and Doescher, and independently byBorsche and Lange.Houben found that magnesium piny1 chloride, C,oH,7*MgCl, andsulphur dioxide yield dihydropinenesulphinic acid ; with sulphur dis-solved in toluene, thioborneol and bornyl disulphide.On fraction-ating the latter, it decomposed into thioborneol and thiocamphor.Bornyl sulphide, (ClOHl7),S, was prepared by oxidising thioborneol.Borsche and Lange5 obtained thioborneol and the disulphide by thereduction of the sulphonic bromide and subsequent distillation.Wuyts and Cosyns had previously obtained the same thioborneol bythe action of sulphur on magnesium phenyl chloride.A reaction notvery dissimilar from the above is described by Smiles and Le Rossignol,6in which sulphinic acids are formed by the action of sulphur dioxideon aromatic compounds in presence of aluminium chloride.Meyer and Togel7 have shown that Grignard’s reagent may beapplied t o the synthesis of ketonic esters by the action of magnesiumon a mixture of the acid chloride or bromide and a halogenated ester.Thus, magnesium bromoacetic ester and benzyl bromide gave benzoyl-acetic ester, whilst a-bromopropionic ester yielded P-benzoylpropionicester.1 Grignard, Ann. Chi~n. Phys., 1901, [vii], 24, 435 ; Houben, Ber., 190% 35,3 Bull.SOC. Chim., 1903, [iii], 29, 689.Ber., 1906, 39, 2346.7 Annalen, 1906, 347, 55.2519, 3695 ; 1903, 36, 2897 ; 1905, 38, 3796. a Ber., 1906, 39, 3219.4 Wuyts, Ber., 1903, 36, 869.Proc., 1906, 22, 158ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 219Gomberg and Cone 1 have used the reagent for obtaining tetraphenyl-methane and some of its homologues from triphenylmethyl chloride :(C,H,),CCl+ C,H,*MgCl = (C,H,),U + ILIgCl,.Redwtion.-The study of electrolytic reduction of aromatic acidsreferred t o in a previous Report2 has been continued by Mettler.3He uses lead electrodes and an alcoholic sulphuric acid solution of thesubstance at 20-30°, with a current strength of 6-12 amperes per100 sq. cm. of surface, I n the majority of cases the correspondingalcohols were obtained.Whilst isophthalic acid gave the dialcohol,phthalic and terephthalic acids were converted into dihydro-acids, theformer yielding the A3:,-, and the latter the A2:5-acid. Electrolyticreduction has also been applied to camphoric imide by Tafel andB ~ b l i t z , ~ who obtained two isomeric U- and P-camphidones to whichthey assign the following farmuls :CH,-CH-C oa-Carnphidone. B-Camphidone.and also to camphorcarboxylic acid by Bredt,, who obtained borneol-carboxylic acid.Brand,G who has applied the electrolytic method to aromatic poly-nitro-compounds, obtained nitrohydroxylamino- and nitro-azoxy-com-pounds ; o-nitroacetanilide 7 in alkaline solution gave o-azoacetanilidetogether with traces of the azoxy-compound, in mineral acid solution,o-phenylenediamine and in acetic acid solution 2-methylbenziminazole.o- Ni troace tanilide.2-Methybenzimiiiazole.Among other reducing agents which have been studied in conjunc-tion with polynitro-compounds is hydroxylamine in alkaline solution,which has been introduced by Meisenheimer. The results obtained. byMeisenheimer and Patzig with o- and p-dinitro-compounds indicatethe formation of diaci-dinitrodihydrobenzene. For example, o- andp-dinitrobenzene react in the following way :C,H,(NO,), + 2NH,*OH + 2KOH = C,H,(,NO,K), + 4H,o + N, ;the products on acidifying pass into the nitronitroso-compounds.Ann. Report, 1905, 106.Ibid., 1905, 38, 3806.ti Bcr., 1905, 38, 4006.Ber., 1906, 39, 2526, 2533.Ber., 1906, 39, 1461.3 Ber., 1906, 39, 2933.5 Annnlert, 1906, 348, 199.7 Brand and Stohr, Ber., 1906, 39, 4058120 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.The nt-dinitrobenzene behaves quite differently, and yields am-dinitro-m-phenylenediainine as the result of a long series of changesdescribed by the authors in the original memoir.finds sodium hyposulphite to be an active reducingagent for azo-, nitro-, and nitroazo-compounds ; also for quinones anddiketones like benzil, the latter being converted into hydrobenzoin.An interesting case of reduction is described by Willstatter andGoldmann,2 in which the amino-derivatives of benzophenone on reduc-tion with tin and hydrochloric acid undergo condensation into ethylenederivatives.p-Dimethylaminobenzophenone, for example, yields tetra-methyldiaminotetraphenylethylene :Grandmougin2Me,N(>Ph :O -+- Ne,N<_)CPh:CPh/-\NMe,.\-/A very important case of reduction is one described by Semmler,s inwhich he shows that y-, 3-, and r-glycols can be readily obtained fromthe corresponding lactones by redaction with sodium in alcoholicsolution.Ozidcction.--Harries 4 ha5 continued his study of the action of ozoneon organic compounds. He shows that unsaturated alcohols as wellas unsaturated hydrocarbons combine with a molecule of ozone andform ozonides. On the other hand, unsaturated ketones, aldehydes,and monobasic acids take up four atoms of oxygen, one moleculeof ozone attacbing itself to the double link C:C and the fourth atomof oxygen to the carbonyl group C:O.The structure of the lattergroup of ozonides and their decomposition by water may be illustratedin the case of the ozonide of mesityl oxide :0 Q + H,O=CMe,<b + COMe-CHO + H202. '' 0 CH. CMe :O:OThe acetone peroxide which is formed subsequently breaks up bythe action of another molecule of water into acetone and hydrogenperoxide. The author sums up the action of ozone under two heads :the molecule of ozone either attaches itself as 0, and forms an ozonide,or it breaks up and yields a labile peroxide. The ozonide method hasbeen utilised for obtttining a variety of rare preparations, such aslevulinaldehyde, as well as for ascertaining structure.I n this uonnexion the formation of a triozonide of benzene (I) and atetraozonide of diphenyl (11) is cited in opposition to the centricformula for benzene.Naphthrtlepe (III), on the other hand, givesa diozonide, and indicates therefore a diihrence in the structure of thetwo nuclei :Ber., 1906, 39, 3561, 3929. Ibid., 3765. Ibid., 2851.Annalen, 1906, 343, 311ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 121J.I n a later paper 1 Harries and Neresheimer point out that theunsaturated hydroaromatic compounds are sharply distinguished fromthe open chain compounds and members of the aibomatic series by theirstability in presence of water. Tetrahydrobenzeneozonide, to take oneexample, is obtained as a white jelly-like mass, which becomespowdery on washing with ether, and is only decomposed on long boil-ing with water, when i t is transformed into n-adipic acid and a smallamount of the corresponding aldehyde.The oxidation of phenols and amines by means of silver oxide,2which has led to such interesting results in the hands of Will-stPtter and his co-workers, has been the subject of furtherIn the present case benzidine, dihydroxystilbene, and the a zophenolshave been selected for investigation.It has already been stated thatbenxidine in indifferent solvents yields an oxidation product. This hasnow been synthesised and identified, not as diphenylquinonedi-imine(An7iuaE Repoi-t, 1905, 128), but as cliaminpazodiphenyl :The formation takes place apparently through dipbenoquinonedi-imine, which then polymerises, the process being marked by variouscolour changes.p-Azophenol is oxidised by silver oxide or leadperoxide in ethereal solution to quinoneazine :O=(-\=N.N-/-\-*\-/ -\-/- -Quinoneazine.It has a deep orange-red colour. On reduction it changes into a newmodification of p-azophenol, which the author regards as a geometricalisomeride of the original compound. 0- and m-Azophenol are notoxidised by silver oxide, nor is p-azoaniline, but p-dihydroxystilbeneis converted into stilbenequinone. Kehrmann and Prager have usedferric chloride in aqueous solution for oxidising aminophenols, andobtained quinoneimines. For example, 2 : 4-diaminophenol yields2-amino-1 : 4-benzoquinoneimine which was precipitated as dichromateand picrate, but was not isolated :HN=-(-\=o\-/NH,.2-Amino-1 :4-benzoquinoneimine.-I IbM2 3437.Ber., 1906, 39, 2846.Ber., 1906, 39, 3474, 3482, 3492.Ann.Beport, 1904, 122; 1905, 127122 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.I n a further study of the structure of the aromatic purpuric acids,Borsche and Gahrtzl have oxidised the products of the action ofpotassium cyanide on polynitrophenols with potassium hypobromite, andobtained a series of nitrocyanophenols.Chlorination.-The researches connected with chlorination andbromination have followed former lines. Crossley and Hills 2 havestudied the action of phosphorus pentachloride on trimethyldihydro-resorcin, which yields 3 : 5-dichloro-1 : 1 : 2-trimethyl-Aa:4-dihydro-benzene ( I ) and, by loss of hydrogen, 3 : 5-dichloro-1 : 2 : 6-trimethyl-benzene (11).(11.)Chattaway by passing chlorine into an alkaline solution of saccharinobtained one or other of two products, determined by the quantity ofalkali present.The changes are indicated as follows :The latter then breaks up in presence of excess of alkali :A research on the chlorination of the substituted oxamides4 basyielded results not very dissimilar from those obtained by the chlorina-tion of the anilides, &c., already reported.A continuation of Zincke’s investigation 5 on the action of bromineand chlorine on phenols 6 is too long to be satisfactorily curtailed, andthe reader is therefore referred to the original papers.An interesting series of additive compounds with the halogens andhalogen acids is described by Hantzsch and Denstorff.7 The seriesis divided into t w o groups named perhuloids, containing bromineand iodine, and hgdrogen perhaloids, containing a certain number ofmolecules of hydrogen bromide and iodide.Among the formerthe best characterised is the tetraiodide of a-diethoxydinaphtha-stilbene and the dibromide of the same compound,OI,Et*C,,H,*CH :CH*C,,H,*OI,Et.Dixanthylene apparently gives products up to the decaiodide.Ber., 1906, 39, 3359.Ibid., 1905, 87, 1882.Annalen, 1906, 343, 75, 100 ; 349, 67 ct seq.Ann. Report, 1904, 95,Trans., 1906, 89, 875.Ibid., 1906, 89, 155.Annulen, 1906, 349, 1ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 123Dibenzylideneacetone gives an additive product mhich containshydrogen iodide and iodine (CI7Hl40),,HI5, and dimethylpyroneforms a compound, (C,H,O,),,HBr,.They are precipitated by mixingsolutions of the constituent substances as dark-coloured, amorphouscompounds, which can also be obtained in the crystalline condition.The union of the halogen and halogen acid is a very feeble one, andappears t o be partly broken by solution in indifferent solvents.Nevertheless, the cryoscopic results point to the actual existence ofthese compounds in solution. A. Werner1 has studied the behaviourof aromatic dibromides (containing bromine in the side chain) towardsalcohols and phenols, and found that an ortho- or para-methoxylgroup greatly enhances the reactivity of the a-bromine atom, so thatby warming with the alcohol or phenol the bromine is replaced.Thus, o-methoxycinnamic dibromide and ethyl alcohol combine asfollows :\-/ '-\CHBr*CHBr*CO,H + 2EtOH = <\CH(OEt)*CHBr*CO,Et -/Anisylideneacetophenone dibromide shows a similar behavipur :O*CH, O*CH,+ HBr + H,O.The difference in reactivity is manifest by comparison with thedibromide of cinnamic acid, which is not affected by alcohol.Diaxotisation.-An interesting case of steric hindrance in connexionwith the diazo-reaction is recorded by Schmidt and Schallj2 who findthat whilst the 4-aminodiphenic acid is readily diazotised, only one ofthe amino-groups in the 6 : 6'-diamino-acid is attacked, whilst the6-aminodiphenic acid cannot be diazotised :CO,H CO,H C0,H CO,HNH2 NH, H,N/-L/-\ /-\ /-'\-/ \-/ \-/ \2Morgan and Micklethwait 3 have attempted to ascertain the structureof the p-diazoimino-compounds described in the AnnuaE Report for lastyear (p.108) by studying the constitution of the diazo-compound frombenzenesulphonyl- 1 : 8-naph thylenediamine. They conclude that theBer., 1906, 39, 27. Ibid., 1905, 38, 3769.3 Trans., 1906, 89, 4 ; Ber., 1906, 39, 2869124 ANNUAL HEPOIt'rS ON THE PROGRESS O F CHEMISTRY.similarity between this and the p-diazoimide, previously obtained, pointst o similarity in structure, which they represent as follows :i n preference to the iminodiazide formula which was suggested a8 apossible alternative. No anhydride formation of this character hasbeen observed with the sulphonyl derivatives of m-diamines.1The study of the action of nitrous acid on the mixed aliphatic andaromatic bases like W- benzenesulphonylaminobenzylamine,H,N .C,H,*CH,*NH*SO,*C,H,,has disclosed the fact that both ortho- and meta-compounds (the lattermuch less readily) yield diazoimides, whereas the para-compounds donot.The diazoimino-formation depends on the presence of hydrogenin the group NH*SO,'C,H,,for if it is ieplaced no anhydride formation occurs.The structure of the compound obtained by the action of nitrousacid on dibenzoylmethane, which was previously described by Wielandand Bloch,2 has now been identified by them 3 as a diazoanhydride, andis probably formed in the following way :C,H,*CO*F]H=~(OH)*C,H, --3 C,H,*CO*F]=Y *C,H, ~NO NO, NO NO,C,H,*CO* Y=y'c6H5.N:N*OA further contribution by Morgan and Clayton4 on the influence ofsubstitution on the formation of diazoamines and aminoazo-compoundsstudied in the ciise of s-dimethyl-4 : 6-diamino-m-xylene,__ CH3H,C/ \NH*CH,, \--/NH*UH,serves to confirm previous observations that dimethylation of bothsymmetrical and unsymmetrical amino-groups of a dipara-substitutedm-diamine greatly retards but does not entirely prevent the intro-duction of a diazo-complex into the aromatic nucleus of a diamine.Trans., 1906, 89, 1289.Ibid., 1906, 39, 1488.Ber., 1904, 37, 1524, 2524.Trans., 1906, 89, 1054125 ORGANIC CHEMISTRY-HOhIOCYCLIC DIVISION.Meldola and Stephens,l in continuation of former work ( A n n u a lReport, 1903, 106) on the removal of nitro- and methyl-groups in thecourse of diazotisation, show that since 4 : 6-dinitro-rn-anisidine,CH,*ON02<1>NH,,NO24 : 6 -Din i tro - nz- ani d i n e .behaves normally, the rupture of the nitro-group depends on theortho and para position of the diazonium group, and on the presenceof a similar group in the adjacent position.A further study of diazotisation by Meldola and Dale2 has shownthat 4-brorno-2-nitro-1 -naphthylamine, when diazotised in sulphuricacid solution, diluted and heated, loses a nitro-group and passes into adiazo-oxide :Br*CloH,<N2*Hso4 -+ Br*C,,H,<T2 or Br*C,oH5<N2.NO2 0 0The action of diazohydrates on oximes is the subject of a researchby Mai and his collaborators,3 in which a series of condensationproducts of one molecule of diazo-compound with two of the oxime hasbeen obtained.A new method is described by Silberritd and Smart4 for obtainingbistriazobenzene, by which in the place of p-phenylenediamine thep-acetyl derivative is diazotised and converted successively into theacetyl-p-amino triazobenzene and p-aminotriazobenzene, and finally intothe perbromide and the bistriazo-compound.A group of aromatic cyanamides are described by P i e r r ~ n , ~ whoobtains them by the action of a neutral diazobenzene salt on a primarycyanamide :C,H,*N,Cl+ CN*NKa*C,H, = C6H,*N2*C,H,*N H-CN + NaC1.They are acid substances, form alkali salts, take up water in acidsolution, passing into carbamides, and break up on reduction intoaromatic amines and p nminocarbamides.Co?&nsatio.rz.Among the products of condenaation which have latterly attractedattention are the so-called fulgenic acids and f u l g i d e s of Stobbe andhis collaborators.The results of their investigations are contained ina series of papers which have appeared since 1904, and to which aTraiis., 1906, 89, 923.Ber., 1906, 39, 876.Proc., 1906, 22, 156.Tram., 1906, 89, 170.Contpt. rewd., 1906, 143, 340126 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.brief reference has already been made in last year's Annual Report.1The subject has attained some importance in view of the presentuncertain nature of the relation existing between colour and structure.The fulgenic acids are derivatives of succinic acid, the fulgide ofits anhydride, and possess the following general structure (R = aryl oralkyl) :R*CH:F* CO,H (R),:C:F*CO,H (R),:C:Y*CO,HR*CH: C*CO,H R*CH:C*CO,H (R),:C:C*CO,HThey are obtained by condensing aldehydes with succinic ester, orwith y-mono-substituted itaconic esters, thus :CH,*CO,RC,H,* CH: F*CO,RC, H C H : C: C 0,R2C,H,*CHO 3-Q H, CO,Ror C,H,*CHO + C,H,*CH:C*CO,R -The tri- and tetra-substituted derivatives are obtained in a similarmanner, using ketone's and aldehydes in place of aldehydes alone.The f ulgenic acids are crystalline substances which are faintlyorange or yellow in colour.The acids are readily converted into theanhydrides or fulgides by fusion or by the action of acetyl chloridein the cold. They are well-crystallised compounds of a red, orange-yellow, yellowish-green, and brown colour, which exhibit metalliclustre and occasionally marked pleochroism.The colour is closelyassociated with the nature of the radicles present. The anhydridesare converted by alkalis into the corresponding faintly-coloured acids,passing in the process through an intermediate coloured stage, Thefulgides are affected by heat and light, some of them when exposed tobright light changing into highly coloured products, and reverting tothe original colour in diffused light. The reversible change becomesless and less marked with each successive transformation, whilstthe orange or yellow colour becomes paler, until a final condition isreached which represents a new isomeric compound. Similar reversiblecolour changes are produced by heat, with the formation of the sameisomeric substances.But the chief interest connected with these compounds lies in thecolour change effected by the presence of different radicles.Thus,the tetramethylfulgide is colourless, the phenyltrimethyl compoundis sulphur-yellow, the phenyl, diphenyl, and dimethyl compoundsare orange-yellow, whilst the tri- and tetra-phenyl derivatives areorange-red and blood-red respectively.2 Similar results have beenexperienced with other substituents, that is to say, the alkylfulgidesA m . Aeport, 1905, 158. Rer., 1905, 38, 3673ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 127are colourless and the aryl derivatives are coloured, the colour deepen-ing with the number of aryl radicles.1 The introduction of a fury1group in place of phenyl intensifies the t i n t still more ; thus diphenyl-furylfulgide is dichromate-red compared with triphenylfulgide, whichis orange-red.2 The o- and m-nitrophenyl groups also produce a deepercolour than the unsubstituted phenyl group, whilst the p-nitro-grouphas the reverse effect and lightens the tint.3 The methoxyl group inthe phenyl radicle also intensifies the c01our.~The reader is referred to the section on colour and structure(p. 143), in which the above results appear to harmonise well withthe views of Hartley and v.Baeyer.An interesting case of condensation is that of ethyl a-chloro-propionate with aldehydes, which has been studied by Darzens.6Glycidic esters of the formula O< CMe*Co’Et I are formed, the yieldbeing greater in the case of aromatic than of the aliphatic members.Moureu and Lazennec 6 have succeeded in preparing acetylenicnitriles of the formula R*CiC*CN from the corresponding esters andainides by distilling the latter with phosphorus pentoxide.Thesesubstances can be used for obtaining /I-alkyloxy and aryl-acrylic nitrilesby condensation with alcohols and phenols :CHRR,C( OR.,): CH-CN.They break up on hydrolysis into a ketone as follows :R,C(OR,):CH*CN + 3H20 = R,CO*CH, + R’,*OH + NH, + CO,.The products of condensation of o-phthalaldehyde with other sub-stances has been studied by Thiele and Falk.7 They find that ring-formation usually follows, except in the case of Perkin’s reaction,which in the case of acetic acid gives o-phenylenediacrylic acid,C,H,( CH:CH*CO,H),, and phenylhydrazine, which yields a di-hydrazone. Acetone forms 2-acetyl-3-hydrindone, and acetophenonethe corresponding benzoylhydrindone :CH(0H)a/\/\\/\/+- I I C*CO*CH,.CHo-Plith&ldehydc. Intermediate product.Aeetylhydrindone.Ber., 1905, 38, 3897.Ibid., 4081 ; 1906, 39, 392.Compt. rend., 1906, 142, 214.B i d . , 4075.Ibid., 761.Ibid., 211, 338, 450.7 Annalen, 1906, 347, 112128 ANNUAL HEPOR'I'S ON THE PROGRESS OF CHEMISTRY.Also o-phenylenediamine condenses to o-benzylenebenziminazole :CH2/ \ A N - /1 I Ic --I * \/- \/\/NPerkin, jun., and Robinson have condensed a-hydrindone and 4 : 5 -dimethoxy-a-hydrindone with salicylaldehyde and p-methoxysalicyl-aldehyde, with the object of elucidating the structure of certainbrazilin and hsematoxylin derivatives,a-Hydrindone and salicylaldehyde undergo condensation as follows :A continuation of the former researches on the condensation ofphenylpropiolyl chloride with sodium acetylacetone by Ruhemann 2has served to confirm the previous formula assigned to the red com-pound ~ b t a i n e d .~ The transformation from the red compound to acolourless derivative by union with phenylhydrazine, semicarbazide,and hydroxylamine indicates, according to the author, an intrn-molecular change of the following character :Betti has shown that /?-naphthol and formaldehyde condense togetherBy replacing ammonia by hydroxylamine he now with arnrn~nia.~obtains a compound to which the following formula is assigned : 5Clough 4 has condensed benzophenone chloride with U- and P-naphtholand obtained di-a-hydroxynaphthyldiphenylmethane,and di-/3-naphthoxydiphenylmethane, (C,H5),C(OC,oHi)2, respectively.following formul2e were obtained :(C6H5)2C(C10K60H)2~With the sodium salts of the two naphthols, compounds of the0Proc., 1906, 22, 160.l'rn7ts., 1906, 89, 682.Gazwttn, 1906, 36, i, 388.Ann. Report, 1905, 147.Ann.Repol-t, 1904, 99.II'ruw., 1906, 89, 771ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 129Isomeric Change.There are few interesting cases of isomeric change to be recordedduring the past year. Klages and Kessler 1 have continued a formerinvestigation 2 on the isomeric change of ethylene oxides, and showthat diphenylethylene oxide by distillation under low prt ssure or byboiling with concentrated bisulphite solution passes into diphenyl-acetaldehyde :(C6H5),C<IH2 ---+ (C,HS),CH*CHO.The same result has been arrived at by Tiffeneau3 by boilingpp-diphenylethylene glycol with 20 per cent.sulphuric acid, whereasthe diphenylglycol iodohydrin (C,H6),C(OH)*CH21 gives desoxy-benzoin.A similar result was obtained mi th a-phenylpropylene-~@-gly col,which gives phenylacetone on boiling with dilute sulphuric acid,C,H,*CH(OH)*CH(OH).CH, --+ C,H,*CH,*CO*CH,,whilst the iodohydrin is transformed by intramolecular change intoatropaldehyde :C,H5* CH(OH)*CH I* CH, -+ C,H5* C( CHO) :CH,.On the other hand, both phenylethyleneglycol and its iodotiyclrin,C,H,*CH(OH)*CH21, give phenylacetaldehyde.I n a further communication on the subject,* Tiffeneau andDorlencourt show that the molecular changes involved in the con-version of hydrobenzoin into diphen ylace talde hy de and similar trans-formations depend on the stability of the hydroxyl in proximity t o thophenyl group ; for in y-ethylpentylene-py-glycol, and aa-diphenyl-propylene-ap-glycol, in which a hydroxyl is vicinal to an alkyl group,ketones are formed and no interchange of radicles occurs,KRC(OW)*CH(OH)mCH, --+ HRC:C(OH)*CH, -+ RRCH*CO*CH,,whilst methyl- and ethyl-hydrobenzoins change as follows :C,€€,*CH(OH)*C(OH)RR’ -+ C,H,*C(OH):CRR’ --+C,H,*CO* CHKR’.Thus, the hydroxyl is stable in juxtaposition to the phenyl group,and where both hydroxyls occupy this position and are thereforestable, a more fundamental change follows and a shifting of radicleaoccurs.A long paper on a similar topic has also been published by Stoermer.5a Cowpt.reszd., 1906, 142, 1537,VOL. 111. 1CBer., 1906, 39, 1753. Am. Report, 1906, 112.lbid., 1906, 143, 126.Bc?.., 1906, 39, 228F130 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.The author’s object was to obtain glycol ethers, to convert themby hydrolysis into the corresponding glycols, and then by removalof water into aldehydes. The preparation of the glycol etherswas effected by Grignard’s method from ethyl phenoxy- and ethoxy-acetates. Irhe conversion into aldehydes by boiling with dilutesulphuric acid occurred much more readily with the ethoxy- than withthe phenoxy-derivatives.The author found the phenoxyl could bereplaced by the ethoxyl group by boiling the former compound withalcoholic potassium hydroxide under pressure. For example, dipheny 1-phenoxymethylcarbinol from ethyl phenoxyacetate and magnesiumphenyl bromide on boiling with alcoholic potash gave the corre-sponding ethoxy-compound,OH*CPh2*CH2*OPh -+ OH*CPh2*CH2*OEt,and on decomposition with 20 per cent. sulphuric acid, diphenyl-acetaldehyde, I n this way a series of both aromatic and aliphaticaldehydes was prepared.The above changes are clearly associated with the pinacone-pinacolinconversion referred to in the Asznucd Report of last year,l a processwhich has been submitted t o further investigation by Delacre withoutleading to any definite result.The structure of a- and P-benzo-pinacolins has also been the subject of a fresh investigation byWertheimer 3 and also by Delacre.4 Whilst the former considers bothcompounds to be oxides of the following formuls,QHPh* YGH4CPh2-0 9Delttcre is of opinion that the structiire of neither is fullyestablished.To the same order of phenomena belongs Wallach’s observation ofthe conversion of cyclopentane glycol by heating with dilute sulphuricacid into cyclopentanealdehyde :YH2*CH CH2*CH2 *>C(OH)*CH.OH -+ C H 2 * C H 2 > ~ ~ o ~ ~ ~ . &2eGH2Another interesting case of isomeric change is described by Johnsonand Jamieson.6 They find that the benzoyl derivatives of un-symmetrical *-methyl- and 3-ethyl-thiocarbamides pass, on boilingtheir alcoholic solutions, or by heating them above their meltingpoints, into the stable symmetrical compounds :NBz,*C(SMe):NH --+ NHBz*C(SMe):NEz.Ann.Beport, 1905, 110.Xonntsh., 1906, 26, 1533.5 Anmxlcn, 1906, 347, 316.Bull. Xoc. china., 1906, [iii], 35, 343.Bd1. Acad. Aoy. Belg., 1906, 7.Anaer. Chem. J., 1906, 35, 297ORGANIC CHEMISTRY -HORIOCY CLIC DIVISION. 131The two classes of compounds are easily distinguished by theirbehaviour with alkalis and hydrochloric acid. The former aredecomposed by alkalis into monobenzyl-$-carbarnides and benzoic acid,whereas the latter are dissolved and precipitated by acids unchanged.On boiling with hydrochloric acid they are decomposed into mercaptaasand dibenzoylcarbamides,Titherley and Hicks last year isolated two benzoyl derivativesof salicylamide, the one melting at 144' readily changing into theother melting a t 208'.The relation between the two compounds wasthen expressed by the amide and iminohydroxy-formulae :BzO*C~H,*CO*NH, -+ BzO C,H;C(OH): NH.This view was contested by Aumers. The authors2 now suggestanother interpretation, according to which the more stable compoundmelting a t 208" has the following constitutiou :CO N HBzCGH4COR fand its conversion into the more labile compound on the one hand andinto the N-ester on the other is brought about by a series of reversiblechanges :CO*NH, -+ ,,<CO*YH - CO-NHBzC6H4<()Bz +- 0-C(0H)Ph +-- -+ C6H,<()HFinally, mention should be made of the action of light on benz-aldehydephenylhydrazone, which, according to Chattaway,3 changesinto the isomeric azo-compoundCGH,*CH:N*NH*CGH5 Z C,H,*CH,*N:N*C,H5.Unsatui-ated Compounds.Gomberg and Cone4 return to the discussion of the structure oftriphenylmethyl, to which reference has already been made.') Theydiscard the hexaphenylethane theory, on the ground that both tetra-and penta-phenylethane are entirely stable substances, and there is noreason for assuming that hexaphenylethane should differ in thisrespect from the other two, Tho oxidisability and reactivity withiodine exhibited by triphenylmethyl are opposed to the htability whichone would infer from a union between two nuclei as represented in thequinonoid formulce of Heintschel and Jacobson. If either formula iscoirect, i t should manifest itself by the behmiour of the p-halogen1 TmrLs., 1905, 87, 1207.IhkZ., 1906, 89, 1.318. Proc., 1906, 22, 36.Bcr., 1906, 39, 3274. Ann. Beport, 1905, 117.K 1352 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.derivatives of triphenylmethyl. The formulze of Heintschel andJacobson would represent these substances as follows :[(XC6H4)2C:/=\/'j (XC,H,),C:/=\/ 6\=/\ i d \=/\C( C6H,X),(X = Cl).I n both cases the chlorine atom in the quinone nucleus, indicated bythe asterisk, should be removable by zinc or silver, thereby linkingtogether two molecules of the original compound. The authors havesubmitted this view to a critical experimental examination by study-ing the behaviour of a series of halogen derivatives of triphenylchloro-methane.From the resulbs, which can only be traced here in outline,they consider that the problem is not yet definitely solved. Thecoloured products, which are formed by the removal of the '' carbinol-chlorine " -with molecular silver from the haloid derivatives oftriphenylchloromethane, must possess the same structure as triphenyl-methyl, since they all give peroxides under similar conditions ; but t h i sstructure cannot be represented by (XC,H,),C-that is, as a derivativeof triphenylmethyl-since it assigns the same function to all threephenyl groups. This cannot be the case, as they show that the halogenof one of the phenyl groups is removable, and therefore one phenylgroup possesses a different function from the other two.Theyattribute this to the probable presence of a quinonoid structure ofsome kind, but different from either of those proposed, and considerthe coloured products obtained by the removal of halogen to be relatedto the triphenylmethane dyes.Thiele and Buhnerl have studied the reducing action of thealuminium-mercury couple on certain fulvene derivatives. Theseunsaturated hydrocarbons were first obtained by Marckwald by con-densing aldehydes with indene. They have a yellow colour, arid areregarded as derivatives of the hypothetical hydrocarbon namedfulvene :The authors find that reduction with the couple takea place readilyif there is a phenyl or carboxyl group attached t o the unsaturatedcarbon group outside the ring, and at the same time the yellow colourAwnnlex, 1906,,347, 249 ; 348, 1.Bey., 1895, 28, 1501ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 133vanishes.indene,Thus, yellow benzylideneindene yields colourless benzyl-gH-CGH5 (p,*C,%C C/\/\CH /\/\CH '\/-I I IlCK ---+ 1 I-ICH, \/Benzyliodene. Benzylideneindene.whereas dimethylfulvene is not reducible :Dim ethyl fulven e.The reducibility also appears to depend on the presence of t h e cyclo-pentadiene ring, for whilst bisdiphenylene-ethylene (I) is reducible,tetraphenylethylene (11) is not :/--\ /-\\ / \ // \/-\ /-\\-/ \.-/--\c:/-11.The result thus contradicts H. Wislicenus's rule that the couple isnot adapted to the reduction of aromatic nuclei or double bonds in opencarbon chains.Where reduction occurs with a conjugated double bond the additionof hydrogen usually, although not invariably, follows Thiele's rule.1The authors find further that benzylindene undergoes condensationwith benznldehyde, yielding a yellow hydrocarbon t o which they assignthe formula of benzylbenzylideneindene :This hydrocarbon also takes up hydrogen on reduction, and gives acolourless product of the formula :1 Ann, Beport, 1904, 105134 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.A further interesting outcome of this research is the proof thatbenzylindene obtained by Tbiele, as described above, and Marckmald'sbenzylindene, prepared by direct benzylation of indene, are identical,and that the same is true of the reduction products of benzylanisylidene-indene and anisylbenzylideneindene, the first of which is obtained bycondensing benzylindene with nnisaldehyde, and the second by con-densing anisylindene with benzsldehyde. The identity of these pairsof compounds is explained by the presence of an '' oscilhting doublebond " :CH*C,H,*O*CH, CH2.C,H4*O* CH,I /\A /\AI I I~H,*C,H, I I\/-- \ / - - ~ H - c , H ~An interesting class of new compounds was described last year byStaudingerl under the name of Letenes, having the general formulaR,C:CO.They have since b3en the object of furtherstudy.2 Diphenyl-ketene is obtained by the action of zinc filings on chlorodiphenylacetylchloride,(C6H,),CC1*C0C1 -+ (CGH5),C:C0.Diphenyleneketene is prepared in a similar fashion from chloro-diphenyleneacetyl chloride, and in properties resembles diphenylketene.It is a yellow crystalline compound, which melts a t 90-90.5O anddecomposes in a vacuum at 150'.It is extremely sensitive to water,combining with it and forming diphenylene-acetic acid, and withalcohol forming the corresponding ester. It also combines with anilineto form the anilide, and with phenylhydrazine to form the hydrazide.If the precipitate of zinc chloride and ketene obtained in the course ofits preparation is exposed to the air, a new compound is produced, towhich the author assigns the following formula :The investigations of Posner, referred to in last year's Report,(p. 115) on the behaviour of unsaturated compounds have been~ontinued.~ In the present case the author has studied the union ofhgdroxylamine with cinnamic and p-methylcinnamic acids, and obtainedP-hydroxylaminophenylpropionic acid, C,H,*CH(NH*OH).CH,*CO,H,and the corresponding p-tolyl compound.A number of their deriv-atives are described and their structure discussed. The preparationof a- chlorocinnamic and chloroccllocinnamic acids is described bySudborough and James.4 Both compounds are formed fromIbid., 3515, 3705. 1 BEY., 1905, 38, 1735. Ibid., 1906, 39, 3062.Tram., 1906, 89, 105ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 135up-dichloro-P-phenylpropionic acid by removal of hydrogen chloridewith alkali, and the acids are subsequently separated by crystallisationof the barium salts in a similar fashion to the bromine derivatives.The conditions of interconversion of the allo-acid and its isomeride arediscussed.Derivatives of Hydvocarbons with Condensed Nuclei.Among the multitude of new naphthalene, anthracene, andphenant hrene derivatives which have been produced during the year,mainly in connexion with the colour industry, and to which from wantof space reference cannot be made, the following possess a certaintheoretical interest :Atkinson and Thorpe have succeeded i n synthesising ethyl1 : 3-diaminonaphthalene-2-carboxylato (11) by condensing ethyl sodio-cyanoscetate with benzyl cyanide, and treating the product (I) withstrong sulphuric acid :I.11.Orchardson and Weizmann 2 have prepared chloronaphthacene-quinone and certain other derivatives from hydroxynaphthoylbenzoicacid ;CO O H co C1And Dienel and Lzgodzinski * have independently obtained1 : 4 anthraquinone, using the following method :0 co II /\/\/\I l l /\/\/\/ co1 : 4-Anthraqninone.a-Anthrol (I) is converted by nitrous acid into 2-(11) and 4-(llI)Trans., 1906, 89, 115.Bcr.) 1906, 39, 926. Pt.oe., 1905, 21, 305.Ibicl., 1717136 ANNUAL IlEPORTS ON THE PROGRESS OF CHEMISTRY.nitroso-1-anthrol, from which by reduction and subsequent oxidation1 : 2- and 1 : 4-anthraquinone are formed :I. 11. 111.The important discovery by Vongerichten and Schrotter in 1881, thatmorphine when distilled over zinc dust yields phennnthrene, has givena definite direction to the study of derivatives of this hydrocarbon.Further investigation has shown that morphol-an integral pnrt ofthe morphine molecule-is a dihydroxyphenanthrene :OH O HThe dimethyl ether of this phenol has since been synthesised bySimilarly, thebaine contains the complex Pschorr and Snmuleanu.14-hydroxy-3 : 6-dimethoxyphenanthrene :Me0 OH OM0/ \-/--\\-/ \ / * \-/-Morphenol, another morphine derivative, has now been converted byVongerichten and Dittmer into trihydroxyphenanthrene,OH OH OHwhilst Pschorr and his collaborators 3 have succeeded in building up aseries of hydroxyphenanthrene derivatives.The method is similar t othat used in the preparation of 3 : 4-dirnethoxyphenanthrene, of whichthe following single example must suffice. Condensation is effectedbetween o-nitrovanillin methyl ether, sodium o-tolylacetate, and aceticanhydride.A nitrocinnamic acid derivative is obtained, which, onreduction and diazotisation, gives 3 : 4-dimethoxy-8-methylphenan-threne :1 Ber., 1900, 33, 1810. Ibid., 1906, 39, 1718,Ibid., 3106ORGANIC CHEMISTRY-HOMOCYCLIC DIVTSIOPI’. 137c HII@-ocyclic Cornpounds.Sabntier and Mailhe 1 have successfully applied the well-knownnickel reduction method 2 to the xylenols, and obtained the correspond-ing djmethylcyclohexanols.Perkin, jun., in conjunction with Simonsen,3 has continued hisresearches on the synthesis of bridged rings. The action of sodiummalonic ester on tribromopropane gives rise t o a dibasic ester,C,,HI5O2Br, which loses hydrogen bromide with potassium hydroxide.The product after hydrolysis loses carbon dioxide on heating and istransformed into a monobasic acid, t o which the authors assign one ofthe following formulae :C H, : F H 2 > ~ ~ * ~ ~ , ~ C--- C H = p IC H,-CH CO, H ’A second ester containing bromine, C,,H,O,Br,, which is formed atthe same time, is supposed t o possess the constitution 111, and loseshydrogen bromide with potassium hydroxide, yielding an acid whichprobably has the structure represented by I V :CH2:Y*CH2--F0,HCH:CH*CH111. IT.A similar class of hydrocyclic compounds t o those of formula TVhave been studied by Wallach.4The siibstances are obtained by condensing cyclic ketones withbromoacetic ester and zinc.The ester of the hydroxy-acid thusformed loses water when heated with potassium hydrogen sulphate,and passes into a n unsaturated acid.The latter in turn lose carbonCon@. rend., 1906, 142, 553.Proc., 1905, 21, 256; 1906, 22, 133.Ann. Beport, 1904, 93.4 n?i,aZcrt, 1906, 345, 139 ; 347, 316138 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.dioxide on heating and give methylene hydrocarbons, although theauthor does not commit himself to the vic 7v that the double-link isnecessarily in the side-chain. These unsati xted hydrocarbons formnitrosochlorides and glycols in the usual maj The latter part with amolecule of water in presence of acids and ve saturated aldehydes(see p. 130). The following scheme represen the changes which ar0supposed to occur :F>C(OH)*CH,*CO,H -+ F>C:CH, -+ R KPerkin, jun., and Kay,l by condensing butane-ap8-tricarboxylicacid by heating with sodium, have obtained ethyl cyclopentanone-2 : 4-dicarboxylate and from i t the monocarboxylic acid,I n a similar manner, ethyl pentane-ayc-tricarboxylate yielded ethylcyclohexanone-2 : 4-dicarboxylate :Wedekind and Weisswange2 have studied a new process for pre-paring diketones of the cplobutane series by removing hydrogenchloride from acid chlorides with triethylamine.isoButyryl chlorideyields 1 : 3-diketotetramethylcyclob~i tane,S(CH,),CH*COCl --+ (CH,),C<~~>C(CH,),.Bauer and Breit have obtained cyclobutane derivatives from/3-benzyl-/I-styrylpropiophenone (from magnesium benzyl halide andcinnamylideneacetophenone, C,H,*CH:CH*CH: C€€*CO* C,H,), andsimilar compounds by heating with equal parts of glacial acetic andsulphuric acids :C,H,* CH: QH C,H5-yH*yH,C6H5*CO*CH*CH*CH,*C6E€,* -+ C,H,*Co* c H,*CK*CH,* C,HGrignard's reaction has also been utilised by Freundler * for obtain-Trans., 1906, 89, 1640.i b i d ., 1916.Bcr., 1906, 39, 1631.C m p t . rcntl., 1906, 142, 343ORGANIC CHERIISTRY-HOR'IOCTCLIC DIVISION. 139ing cyclohexylacetone from magnesium hexahydrobenzyl iodide andacetaldehyde :C,HI,*CH,*MgI + CH,-CHO -+ C,H,;CH(C H,)*OMgT: -+CGH,, *CH,*CH(OH)*CH, + 0 -+ C,H,,*CH2.CO*CH,.Also by Wallach 1 for preparing methylsuberone and other heptacyclicderivatives. The stages of the process will be sufficiently indicated bythe following formuls :Aldehydes of cyclohexane have been obtained by Darzens andLef6bure by condensing cyclohexanone with monochloroxcetic ester andsodium ethoxide.The glycid ester is easily hydrolysed, and the free <I>&&...". *CO,Et,acid on distillation in a vacuum converted into hexahydrobenzaldehydeby loss of carbon dioxide.The comparative study by Crossley and Renouf of dihydro-laurolene, dihydroisolaurolene, and 1 : 1-dimethylcycZohexane has ledto the conclusion that dihydroisolaurolene is 1 : I : 2-trimethylcyclo-pentane and not a cyclohexane derivative, as proposed by Zelinskyand Lepeschkin, a conclusion which has been fully attested by Blanc'ssynthesis of isolaurolene (p. 141).CH2*$!(CH3)2 1 FH*CH,.CR,*CH,Di hy droisolaurolene.I n series of interesting papers, Knoevenagel and others* discussthe structure of two compounds obtained by Pinner 5 and by Kerp andMiiller by condensing acetone with itself, and termed xylitones. Theyappear to be derivatives of cyclohexenone, but although the authorshave succeeded in synthesising a similar substance by condensingAnnnnlcn, 1906, 345, 139.See A m .Eeport, 1905, 120.Ibid., 1882, 15, 586.Trans., 1906, 89, 26.BET., 1906, 39, 3441 el scq.6 Annnlen, 1898, 299, 203190 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.phorone with ethyl scetoacetate, the constitution of the xylitones isstill unknown.Terpenes and Camphors.Among the synthetic preparations of members of the terpene andcamphor group' the following may be mentioned. Perkin, jun.,l hassucceeded by methods previously described in obtaining tertiary men-thol and A3-p-menthene from 1 : 4-methylcycZohexanone and magnesiumGopropyl iodide.Kay and Perkin, jun.,2 have also been successful inobtaining the active modification of A3y-menthenol and A3 ' s(9)-p-menthadiene by first resolving the 1-methyl-A3-c~cZohexene-4-carb-oxylic acid into its enantiomorphs. The subsequent stages in thesynthesis have already been described.3A synthesis of menthene is also recorded by Wallach* by con-densing 1 : 4-methylcyclohexanone and ethyl a-bromoisobutyrate withzinc. The acid obtained from the product by hydrolysis loses carbondioxide on heating and passes into i-A4(8)-menthene, and on boilingthe latter with sulphuric acid into i-A-3-menthene.H CH, H CH,\/ \/ICO,Et*C(CH,),/\(CH,),t: OHC0,EtH CH, H CH,\/ \/ICH, CH CH,A further synthesis of and of active A3 ' *@'-menthadiene isdescribed by Semmler and Rimpel.5 The starting point is a-citron-ellal (I), which is converted successively into isopulegole (II), iso-pulegyl chloride (III), and by the action of sodium and alcohol intoAs(9)-mentbene (IV) :CH-CH, CH*CH, CH'CH, CH-CH,H,O/\CH, H,C'/\CH, H , C A C H , H,C/)CH,OHCl ICH, (H0)HCI JCH, ClHCI/UII, H,Cl / \/ .\ P H 2QH2 7" Q* QHC H,: C-CH, CH,: C'CH, CH,: C-CH, CH,: C-CH,1. 11. 111. IV.1 Tram., 1906, 89, 832. ]bidd,, 839. Ann. Report, 1905, 123. * Ber., 1906, 39, 2504. Jbid., 2582ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 141If isopulegyl chloride dissolved in quinoline is dropped into quino-line heated to 200-2 1 Oo, it is transformed into A3 : s(g)-menthadiene.Semmler and McKenzie have also succeeded in obtaining Buchu-camphor (found in the leaves of Bcwosina betulinna) synthetically.Itrepresents the enolic form of p-menthadione-2 : 3 (11). The synthesiswas effected by the aid of hydroxymethylenementhone (I)z, which isoxidised by means of ozone.CH*CH, CH-CH,H ,c/) c : c H ( o H ) H,C/\CO--3 H,d ICOH2C(/C0 \/C'H.C,H, CH*C,H7I. 11.The diketone undergoes isomerisation under the influence of acidsand alkalis to the enolic form, which is identical with the naturalproduct .Among other interesting syntheses is that of isolaurolene and isa=lauronolic acid by Blanc,, and camphoric acid by Perkin, jun., andT h ~ r p e . ~ Blanc's synthesis is effected by distilling aa-dimethyladipicanhydride under pressure, when i t changes into dirnethylcyclopentanone,The latter yields with magnesium methyl iodide and decomposition ofthe product a tertiary alcohol, which on distillation breaks up intowater and isolaurolene :yH,*C(CH,),*CO*Y FH2C(CH3),*C')0 ~H2*C(CH,),'~(0H)*CH,,FH,*C(CH,),*~*CJHaCH,---CH,-CO CH,--- CH, CH,---- CH2CH,-- CHisolanrolene,The starting point for the new syntliesis of cainphoric acid is y-bromotrimet hylcyclopentanecarboxylic acid or its ester. The compound whenshaken with a mixture of potassium cyanide and hydrogen cyanide andthen heated gives an acid, which on boiling with acetic anhydride iaBey., 1906, 89, 1158, See A m , Chini.Phys,, 1904, [viiil, 3, 49,Trans., 1906, 89, 795.ii G'oinpt. reid., 1906, 142, 1084142 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.converted into i-camphoric anhydride, and from this camphoric acid canbe prepared :CH,*$!MeBr CH,. ?Me* C0,HCH,~H*CO,H CH,*CH*CO,HI CMe, -+ I y3-fe2The numerous researches connected with the study of the structureof terpene and camphor derivatives can only be briefly indicated.Harries finds by the ozone method that guttapercha contains the samefundamental hydrocarbon as Para rubber, namely, 1 : 5-dimethylcylo-octa-Al: -diene, for it yields the same decomposition products.2Wallach and Laiitsch3 have made a study of the structure ofisocarvoxime, which is formed when carvoxime hydrochloride or hydro-bromide is treated with alcoholic potash.As the substance is inactive, the choice of formulz lies between thetwo following :OCH, C*CH,HC/\C:NOH HC/\C:NOHH,C!,)CII, HC\\/CH,C:C( CH,), C*CH(C H 3)2I.11.Further, isocarvoxime when heated with dilute sulphuric or oxalicIt is a hydroxycarvacryl- acid is converted into a base cccrvoline.amine,C*CH,HCH\C*N H,H C ~ ) C H IC*C(OH) (CH,),Cltrvoline.and the mechanism of its formation from isocarvoxime (I) through (11)is fully discussed by the author.I n connexion with the terpenes, the study of nerol by v. Soden andTreff 4 should be mentioned. The authors describe a t length its methodof separation, the preparation of numerous derivatives, and itsbehaviour with various reagents. Without discussing these in detail,it may be stated that the authors conclude, from the close similarityexisting between geraniol and nerol, that the constitution of the twois very similar, and the association of nerol with linalool in essentialoils points to an isomeric change in the latter under the influence ofvegetableacids.They assign one of the following formulz to the com-Ber., 1905, 38, 3985.i:?LllnZc?t, 1906, 346, 26U.Am. aeport, 1905, 126.Ber., 1906, 39, 906ORGANIC CHEMlSTRY--HOMOCY CLIC DlVISION. 143pound, but give preference to the second, in which the central doublebond of geraniol is displaced :C,H,*CH,* CH,*CH : F*C,H ,*OH C,H,* CH,*CH,*CH,*;Ci! C,H4* OHI n another paper by Zeitschell on the same subject, the authorcomes to the conclusion that geraniol is stereoisomeric with nerol. Heshows that by the action of acetic anhydride and other reagents linaloolcan be converted not only into geraniol and terpineol, but into nerol,by a process of isomeric change.The two stereoisomerides are furthershown to be directly connected with the isomeric citrals s and b, whichare likewise stereoisomeric :Cfrl[, CH,(CH,),C: CH*CH,* C H ,*$* CH,Citral n = Geranisl.(CH,),C: CH* CH, CH,-;c;'*C H,HC*CHO CHO-CHCitral b =Nerd.(CH,),C:CH*CH,*CH,*;c;'*CH, (CH,),C:CH*CH,* CH,*g* CH,Geraniol. Nerol.The conversion of pinene hydrochloride into borneol and bornylacetate has been effected by Houben, by means of magnesium.Magnesium piny1 chloride, which is formed, is exposed to a current ofoxygen and then decomposed with sulphuric acid or acetic anhydride.I n the former case borneol, in the latter the acetate, is formed :HC*CH,*OH HO* CII,*CHCloHl~.MgC1 + 0 -+ C1,H,7*OMgC1 -+ CloH17*OH + Mg(0H)CI.CloH17~OMgC1 + (CH,CO),O = Cl,H17*O*CO*CH3 + CH,DCOeBIgC1.Tilden and Shepheard 3 find that magnesium methyl iodide convertsa- and p-limonene nitrosochloride into isomeric compounds of the formulaC,,H,,ON,Cl, by removing oxygen from the bisnitrosochloride.Rupe and Liechtenhan4 have obtained from carvone by means ofmagnesium methyl iodide a hydrocarbon, CllH16, and a small quantityof a ketone, CllHl,O, of unknown constitution.A long and importantpaper on derivatives of pinene by Wallach does not admit of usefulabstraction, and the reader must be referred to the originalmemoir.Colour and Structure.I n the two former Repoyts an indication was given of the direction ofresearch on the relation of colour to structure, and a brief referencewas also made to the results which might be anticipated from the workof Hartley and others on absorption spectra.During the past yearBet-., 1906, 39, 1780. IBid., 1700. Trans., 1906, 89, 920,Be?'., 1906, 39, 1119. Annalen, 1906, 346, 220144 ANNUAL BEPORTS ON THE PROGRESS OF CHEMISTHY..the subject has been actively pursued, and many of the views formerlyadvanced have been modified, matured, or moulded into definiteshape.The absorption bands in the ultraviolet portion of the spectrum of alarge number of coloured and colourless compounds have been sub-mitted by Hartley and his collaborators to careful examination andmeasurement, and have led him to the following views on the structureof coloured substances.The formation of a colouring matter from abenzene derivative depends on the introduction of such modificationsof the structure of the molecule as will displace the absorption bandstowards the visible portion of the spectrum; that is, by retarding therate of oscillation. But whilst the colour depends on the peculiar kindof oscillation of the benzene ring, the retardation may be effected byreplacing hydrogen by hydroxyl or amino-groups (Witt's auxochromes)or by the condensation of several benzene nuclei. Thus, the condensa-tion of three benzene nuclei into triphenylmethane is manifestedby the decrease in number of oscillations and increase in theirintensity, whereby the bands are displaced to the edge ol the visiblespectrum. The characteristic six bands OF benzene become fused intoa broad band on the fringe of the ultraviolet.These views have beenaccepted by v. Baeyer, for they appear to harmonise with his latestinvestigation on the relation of colour to structure.'The coloured solutions of o-trianisylcarbinol and o-hydroxytriphenyl.carbinol in acetosulphuric acid are no longer ascribed to the union of theacid with the quinone oxygen which becomes quadrivalent, for the de-composition of the salt by water should give a t least a passing indicn-tion of the formation of the coloured quinone :CH CHt lCPh,I ICPh,But this only occurs where there is R hydroxyl already in the paraposition to the carbinol group.It therefore follokvs that the colour oftriphenylcarbinol salts is not necessarily connected with the quinonestructure of its hydroxy- or halogen derivatives. v. Baeyer consequentlypeturns to his original view, according t o which the cause of colour isdue to the multiplication of benzene nuclei in triphenylcarbinol. Thechromophore includes the whole complex which already possesses thepower of manifesting colour, and only requires a chemical change sucha8 that produced by union w i t h sulpliuric acid to make it evident. I nthe language of Witt, triphenylmethane is the chromophore and theZeit. nngew. Chem,, 1906, 29, 1287ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION.145sulphate group, the auxochrome. The authoi; has prepared varioushydroxy -derivatives of f uchsone which dissolve in alkalis withcharacteristic colours, para with violet, ortho with blue, and metawith blood-red. To these compounds, which may be regarded asanhydrides of a p-hydroxycarbinol, theis given :f ollo wing q uinvnoid structureR C/\(OH)C,H, C,H,0-, m-, aud p-Hydroxyfuchsone.If excess of alkali is added the colour vanishes, and this is explainedby the addition of the elements of water and the formation of ahydroxycarbinol. The addition of acid reproduces the colour, but at arate varying with the position of the hydroxyl group. The p-hydroxy-fuchsone is precipitated at once as the yellow quinone, whereas the o-and m-compounds separate as colourless carbinols, and only slowly losewater and pass into the quinonoid form.Thus, the hydroxytriphenylcarbinols possess in a varying degree thebasic properties of an alkali, and like the latter lose water on unionwith acids.The same views hold in regard to the amino-derivatives,but in this case i t is necessary for colour to be manifested, that notone but the two amino-groups should occupy a para position to thecentral carbon atom. Why this is necessary is not explained, but thefact remains that with only one quinonoid amino-group the compoundis colourless; but here again many of the salts are coloured. In aformer Report a brief outline was given of Hantzsch’s views on therelation between colour and constitution.He assumed that thechange from a colourless to a coloured substance generally denotes a con-current change of structure. This principle has now been applied to thenitrophenols. All true nitrohydrocarbons are colourless ; so are thestructurally immobile derivatives of nitrophenols like the ethers andesters. Thus, the nitro-group itself is destitute of chromophoricproperties. On the other hand, certain nitrophenols aud all their saltaare coloured. This has been usually explained by saying that thechromophoric character of the nitro-group is enhanced by the auxo-chromic hydroxyl. The view is contested by Hantzsch, who bringsevidence to show that there exist two series of ethers, namely, colour-VOL. 111.Ann, &eporI, 1904, 122.146 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY.less or true nitrophenol ethers, and coloured quinonoid or uci-nitrophenolethers.They are represented by the general formulze :True nitrophenol ether mi-Ni trophenol etherColourless. Colotired.Every case of colour in the nitrophenol group is explained in thelight of these new facts. Thus, the free nitrophenols which arecoloured consist of a solid solution or equilibrium mixture of the twodynamic isomerides, the colour intensity depending on the proportionof the coloured or mi-constituent present. Picric acid is a case inpoint. The alkali sal ts represent the preponderating mi-form. Onefact requires explanation, The salts of picric acid are much lighter incolour than the mi-picric ethers which have a red colour.Theexplanation is that there are two aeries of ccci-ethers, a light and adark coloured one. The picrates :correspond to the light colouredseries. The change of colour is not only effected by conversion of thenitrophenols into their salts, but by rise of temperature and by solvents.Light petroleum produces a colourless solution, whereas water, withits greater ionising power, produces a certain amount of the colouredaci-structure. Hantzsch, however, does not subscribe to the view thationisation alone produces colour, because the ions of acids which giverise to coloured salts may exist without colour. The existence ofcoloured and colourless nitrophenol ethers which are non-ionisablecompounds is sufficient evidence of the fact.The colour change isessentially n structural or chemical change in the first instance, andionisation is only a secondary phenomenon. Thus the idea ofchromophore and auxochrome as separate and distinct factors in colourproduction does not hold, but the phenomenon of colour is the effectof a chemical interchange which is promoted by their association inthe same compound :Both forms possess a dissociation constant in aqueous solution, butat present there appears no way of determining it. The fact that thealkali salts as well as the free nitrophenols deepen in colour on heatingwhen the uci-form is almost wholly present is ascribed to a changingproportlion of the yellow variety, or to a greater or less dissociation ofthe mi-compound. 0-, m-, and p-Nitrophenols give coloured salts, andtherefore possess a quinonoid structure, although no m-quinonoid ethershave so far been prepared.The many apparently contradictory facts have been so ingeniouslymet by Eantzsch that the theory almost disarms criticism.NotORGANIC CHEMTSTRY-HOMOCYCLIC DCVISlON. 147withstanding, Kauffmann has taken up the defence of the auxochrometheory, and bases it, in the first place, on the change in the position ofthe absorption band produced in benzene by the introduction ofdifferent groups; in the second place, on the existence of colourednitroethers like nitroquinol dimethyl ether, and nitrohydrocarbonslike nitrostilbene. The existence of Hantzsch's colourless ether isascribed by Kauffmann to the weak ausochromic character of theacetonyl and methoxyl groups.Hantzsch in reply points out that theabsorption spectra cannot determine the presence or absence ofauxochromic groups, because no relation has been shown to existbetween them; he throws doubt on the purity of the colouredspecimen of nitroquinol dimethyl ether, and lays aside the question ofthe general structure of coloured substances as outside t,he presentdiscussion, which only embraces those compounds which exhibit asimple change from colourless t o coloured.I n reference to absorption bands, he supports his contention byBaly's observation2 of the similarity of the bands of colourlessp-nitrophenol and its methyl ether, and the great divergence exhibitedby the coloured sodium salt.I n a further paper3 Hantzsch brings evidence to show that thecolour of the salts of colourless phenol aldehydes and their ethers mustbe ascribed to a similar structural change,and the same explanation has been applied to the case of the hydroxy-ketones and hydrovybenzoic acids.A similar principle to that oE Hantzsch has been adopted by Greenand King4 in support of their view of the quinonoid structure of thephthaleins.They bring evidence to prove the existence of colouredquinonoid alkyl esters of the phthdeins such as0: C6H,:C(CGH4* OH)*C,H,*CO,Me,and hence regard the coloured salts of these compounds as possessingan analogous structure, the sodium salt having 'the formula,O*C,H,: C( C,H; OH) *C,H,* C0,Na.The relation of colour to structure is viewed by Bitly and hiscollaborators from a very different standpoint.Hantzsch's ex-planation of colour phenomena is, in a sense, a statical one, depend-ing on a particular structure, which, however, is not necessarily opposedto the views of Hartley, Baly, or v. Biteyer. Bsly's view is essentiallydynamical. The absorption spectra in the ultra-violet of certaincoloured and colourless substances show characteristic bands which areBer., 1906, 39, 1959. ' Uei.., 1906, 39, 3080.Trans., 1906, 89, 518.Ibid., 2365.L 148 ANNUAL REPORTS ON THE PROGRESS OF CHEMISTRY./\I I\/ascribed by Baly to the presence of mobile groups (usually associatedwith dynamic isomerism) which give to the molecule, by virtue of theirpotential tautomerism, a rapid vibration or oscillation termed isorro-pesis. The theory embraces a variety of diverse phenomena such astautomerism, steric hindrance, structure, and colour. Thus, thetautomerism of acetoacetic ester and similar substances is supposedto be manifested by distinctive ul tra-violet absorption bands whichthey exhibit in solution.The reactivity of the a-diketones and quinones is associated withother prominent absorption bands,2 and the colour of some of themembers of these groups is traced to internal oscillations set up bychange of structure in the ketone groups. This change of structure isascribed to the change of residual affinities of the ketone oxygen atoms.The quinonoid structure is regarded as the statical representation ofsuch an internal oscillation which: affects the visible region of thespectrum. The colour of the nitroanilines and nitrophenols 3 isascribed in the same way to oscillations set up by the change ofthe residual affinities of the nitrogen and oxygen and the t w onitrogen atoms respectively :t- --+0 OH\/I I\/N I\HNp-Nitrophenol in alcoholic solution and its sodium salt are re-presented by :0 0 0 ONa 0 ONa\/I I\/N/I\U HThe free phenol is staticalThe same principle has beenmica1 and coloured.and colourless, the sodium salt dyna-applied to determining the structure ofthe isonitroso-compounds which are colourless in the free state andTmns., 1904, 85, 1039.Baly and Stewart, Trans., 1906, 89, 489, 502.13nly, Edwards, and Stewart, Traits., 1906, 89, 514ORGANIC CHEMISTRY-HOMOCYCLIC DIVISION. 149coloured in alkaline solution.1 Finally, the diminished persistence ofthe absorption bands in the case of the substituted quinones isadvanced t o explain the diminished reactivity of the quinone groupformerly attributed by Kehrmann to stericIn summing up the theories of the four chemists whose work hasbeen described, it will be seen that those of Hartley and Baly areessentially dynamical. Colour is manifested by molecular vibration ;but whilst I-Iartley is satisfied with formulating the principle thata particular molecular structure gives rise to bands which bydisplacement may become visible as colour, Baly goes further, andpostulates a potential change of structure as being responsible for theoscillations which are set up, thus manifesting in certain cases thephenomenon of colour. v. Baeyer and Hantzsch confine their attentionto structure, without discussing specifically the nature of thosemolecular oscillations which must be in every case its ultimate cause.Whilst Hantzsch limits his investigation to those compounds whichchange readily from a colourless to EL coloured modification, andexplains the process by a definite isomeric change, Baeyer attacks thebroader question of structure and ,colour, and finds the answer inHartley's theory, which has already been discussed.J. 16. COHEN.Raly, Marsleii, a i d Stewart, Tr'rgns., 1906, 89, 966.Stewart and Baly, Tram, 1906, 89, 618