GRIESS ON ORGANIC COMPOUNDS ETC. VIII.-On a new Class of Organic Compounds in which Hydrogen is replaced by Nitrogen. By PETERGRIESS. 111. THE researches published in my two preceding papers on the substitution of nitrogen for hydrogen in organic compounds were confined exclusively to bodies belonging to the acid type. The idea naturally presented itself of also submitting organic bases to the action of nitrous acid. I have chosen for this purpose those which are closely related to the amido-acids of the aromatic series. I have thus obtained new nitrogen-compounds presenting in their composition and deportment a well characterised series parallel to the diazowids. In order to prepare this body aniline [(amidobenzol = C,,H5 (NH,)] is Zissolved in from six to ten times its volume of ordinary spirit; and a slow stream of nitrous acid is passed into this solution which mmt always be kept cool until the whole of the aniline has disappeared.This point is reached as soon as the oily residue obtained by evaporating a small quantity af the solution on a watch-glass solidifies to a semi-crystalline mass. The solidification however occasionally and especially in the summer takes place after some time only. In that case the completion of the process is easily recogiiised by testing whether the oily residue remains insoluble in dilute acetic acid. If this is the case the current of nitrous acid must immediately be stopped because an excess of the acid mould convert the required snbstance into other new products.The alcoholic solution which is of a brownish-red colour now contains even if the operation has been conducted with the greatest care besides diazo-amidobcnzol a GRIESS ON A NEW CLASS OF more or less considerable quantity of other products which are all generated by the action of nitrous acid upon aniline. They con- sist of phenylic acid benzol a new body to which I have given the name of nitrate of diazobenzol nitrate and nitrite of aniline and perhaps also some unchanged aniline. In order to get rid of these bodies the whole of the brown alcoholic solution is poured into a large quantity of water from which the greater part of the diazo-amidobenzol immediately separates as a brown oily liquid which soon solidifies to a crystalline mass whilst a smaller quantity is deposited from the water on standing for some time in the form of yellow crystals.The crystalline precipitate together with the yellow crystals is separated by filtration from the mother-liquor which contains nearly all the bye-products. The crude diazo-amidobenzol remaining on the filter is first pressed between bibulous paper in order to get rid of the last traces of the mother-liquor then washed several times with cold alcohol and lastly twice or three times recrystallised from boiling spirit whereby it is obtained in golden yellow plates of perfect purity. On analysis it gave numbers agreeing with the formula :-The formation of diazo-amidobenzol is represented by the following equation :-2C,H,N + N1.0 = CI2Hl1N3+ 2H,O.Aniline. Diazo-amidobenzol. Properties.-Diazo-arnidobenzol crystallises in golden yellow lustrous plates rarely in needles. It is insoluble in water rather easily soluble in hot insoluble in cold alcohol. It is miscible with ether in every proportion. It melts at 9l0 forming a reddish-brown oil which resolidifies to a crystalline mass at about 50'. At a higher temperature it is decomposed with rapid evolution of gas. If a larger quantity is heated up to 200" a violent explosion is the result. Diazo-amidobenzol is inod~rous and tasteless. Weak acids are not capable of dissolving it whilst powerful acids decompose it at once with evolution of nitrogen. From this deportment it is evident that the well-defined basic properties of' the aniline have been considerably modified by the replacement of its hydrogen by nitrogen.Diazo-amidobenzol is in fact no longer capable of forming with acids ORGANIC COMPOUNDS ETC. any saline compounds whatever and only in its deportment with dichloride of platinum with which it forms a doiible compound does its show that its basic character has not entirely dis- appeared. Platinum-salt of Diazo-amidobenxol.-C12H,,N,.HCl. PtCl,. This salt is easily obtained by treating an alcoholic solution ( f diazo-amidobenzol with dichloride of platinum and hydrochloric acid when it immediately separates in small reddish needles or prisms. They are thrown on a filter in order to get rid of the mother-liquor and are rendered perfectly pure by thorough washing with alcohol.They are very unstable and are gradually decomposed in a moist atmosphere apparently with formation of phenylic acid. They deflagrate at a high temperature; the platinum cannot therefore be determined by simple ignition. Diazo-amidobenzol and Nitrate of Silver.-On mixing the alcoholic solutions of the two substances a bulky greenish-yellow precipitate is at once obtained which on drying shrinks together very much and is very apt to blacken. Its composition is repre- sented by the formula OF DECOMPOSITION -Dew PRODUCTS OF DIAZO-AMIDOBENZOL. composition by hydrochloric acid. When diazo-amidobenzol is warmed with concentrated hydrochloric acid which has been covered with a layer of ether two atoms of water are assimilated and take the place of two atoms of nitrogen the substance at the same time splitting up as shown in the following equation :-C,,H,,N -k H,O -j-HC1 = C,H,O + C,H,N.HCl + N,.Diazo-amidobenzol. Phenylic Hydrochlorate acid. of aniline. The hydrochlorate of aniline is found in the aqueous hydro- chloric acid whilst the phenylic acid is taken up by the ether. I have not analysed either the phenylic acid or the aniline the presence of both bodies having been sufficiently established by their well-known properties. I have however quantitatively determined the amount of nitrogen evolved during the reaction. I obtained 13.67 p. c. of nitrogen. The preceding equation requires 14.21 p.c. It is highly probable that diazo-a,midobenzol under the influence of anhydrous hydrochloric acid would be decomposed thus :- QRIESS ON A NEW CLASS OF C12H,,N -I-H2C1 = c6115cl + C,H,N,HCl + N2.Diazo-amidobenzol. Chlorobenzol. This decomposition would then be quite analogous to that of diazo-amidobenzoic acid by hydrochloric acid. Action of Bromine upon Diazo-amidobenzo1.-When a moderately concentrated ethereal solution of diazo-amidobenzol is treated with an ethereal solution of bromine it will be observed that every addition of the bromine causes a fresh precipitate of small white plates. As soon as the addition of bromine no longer produces a precipitate the white crystals must be rapidly separated from the mother-liquor by filtration and washed with ether until they are perfectly white.The analysis of this substance which I shall communicate in my next paper has proved it to be a compound ol hydrobromic acid with a new body which 1 have called diazo-benzol. The formula of this hydrobromate is-On evaporating the ethereal mother-liquor from which that com-pound has separated white needles begin to crystallise out possessing all the properties of tribromaniline. The transforma- tion of diazo-amidobenzol with bromine may be expressed by the following equation :-C12HllN3+ 6Br = C6H,N2.HBr + C6H,Br3N + 2HBr. Hydrobromate of Tribrorraniline. diazo-benzol. Action of Nitrous Acid.-If diazo-amidobenzol be dissolved in a mixture of strong alcohol and ether and then treated with nitrous acid white crystals of nitric diazo-amidobenzol make their appear- ance; they are formed according to the following equation :-CI2Hl,N + NHO + 2NH03 = f2(C6H4N,.HN03) + 2H20.Nitrate of diazo-benzol. I shall describe this reaction more minutely in a future paper. In his researches on the substitution-products of aniline Dr. H ofm an n observed that the basic character of aniline is weakened in proportion to the amount of hydrogen replaced by bromine chlorine or hyponitric acid so that for instance tribromaniline ORGANIC CONIPOUNDS ETC. 61 becomes a perfectly indifferent body. The feebly basic properties of diazo-amidobenzol have proved that nitrogen also exerts an acidifying influence upon aniline and even in a higher degree than chlorine Gr bromine. The task presented itself of ascertain-ing whether this phenomenon would also occur with brornanilinc nitraniline &c.and whether the action of nitrous acid upon dibrom- and tribrom-aniline might not even give rise to bodies of a decidedly acid character. In what degree this view has been confirmed by my researches I shall communicate hereafter. I will first of all make a few remarks upon chlorinated and brominated aliiline themselves. AND CHLORINE ON BROMINE SUBSTITUTION-PRODUCTS OF A.NILINE. According to the researches of Ar ppe,* the nitraniline which he Gbtained by the decomposition of pyrotartronitranilide by potash is not identical with that prepared by Muspratt and Hofmann by the reduction of dinitrobenzol with sulphide of ammonium. In order to distinguish the two compounds Arppe has given to his own the nane a-nitraniline whilst that of Muspratt and Hof-mann he has called p-nitraniline.The chlorinated and broniiriated anilines were as is well known originally prepared by H ofm an n from the corresponding chlorinated and brominated substitution-products of isatin. Millsf- has recently described a method for the prepara-tion of these bodies which is preferable to that of Hofmann. It consists in converting acetanilide into brom- or chlor-acetanilide and then distilling these compounds with caustic potassa. Mills has left it undecided whether the substituted anilines thus pre-pared are identical with those of Hofmann or whether they are isomeric like the two nitranilines just mentionecl. The solution of this question was of the more interest to me as the fact of the nitrogen bodies to be obtaiued from the brorn- or chlor-anilines being eventually isomeric or identical could have been decided beforehand.I have therefore carefully compared the properties of Mills’s brom- and chlor-aniline with the corn-pounds prepared according to Hofm ann’s method. I found such a perfect coincidence in the properties of the free bases as Js Ann. Ch. Phsrm. xciii. 357. I. Proceedings of the Royal Society. GRlESS ON A NEW CLASS OF well as of their salts that I have no hesitation in pronouncing them to be identical. Bromaniline accordirig to Hofmann melts at 50' C. 1have on the contrary found that the melting point of brornaniline purified by several recrystallisations is 57' C.Neither could I confirm the observation made by Mills that the bromaniline prepared according to his method has a greater tendency to crystallise in needles. When in a state of purity I have always obtained it crystallised in the form oi octahedrons. The same advantages offered in the preparation of brom- and chlor-aniline according to RIills's method hold good as I have found when preparing dibrom- and dichlor-aniline in a similar manner. In order for this purpose to convert the acetanilide into dibromacetanilide it is suspended in water and treated with bromine until the ~hhole of tlie acetanilide has been converted into a reddish resinous mass. The crude dibromacetanilide thus formed may at once without separating the water be submitted to distillation with potash when the dibromaniline distils over in oily drops which soon solidify to white needles.It may be purified from any tribromaniline with which it is mixed by dis- solving in warm moderately concentrated hydrochloric acid in which the latter substance is insoluble. If traces of bromaniline are present the hydrochloric acid solution is evaporated to dryness and then treated with water. By this treatment the hydrochlorate of bromaniline suffers no alteration whilst the dibromaniline loses its hydrochloric acid and becomes insoluble in water and may therefore be completely purified from bromaniline by washing with water. Recrystallisation from dilute alcohol furnishes the dibromaniline in needles or long plates.Although its preparation and properties scarcely leave a doubt of its identity with the compound prepared according to H ofmann' s method I have yet determined the melting point of each of them and have found them to coincide at 79.5" C.* The hydrochlorate a!so of the dibromaniline prepared by me crystallised in the same shape resembling palm-branches a3 described by H ofm ann. Analysis gave numbers agreeing with the formula :-C6H,Br2N.HC1. * Hofmann states the melting point of dibromaniline to lie between 50" and 60"C. ORGANIC COXPOCNDS ETC. The feebly basic properties which dibromaniline possesses are still manifest in its deportment with dichloride.of platinum A concentrated hydrochloric acid solution mixed with dichlo-ride of platinum yields a double salt crystallising in beautiful yellow prisms.This compound is very unstable and is decomposed even by hot water with separation of dibromaniline. Its formula 1s :-C6H,Br2N.HCl.PtCl,. To prepare dichloraniline through the agency of acetanilide the latter is dissolved in hot water and treated with an excess of chlorine until the crystalline mass which was first deposited has become quite soft. This crude dichloraniline is separated from the mother-liquor and distilled with potash. The distillate must be purified in the same manner as the dibromaniline nichloraniline crystallises like the corresponding bromine-com- pound in white needles which are nearly insoluble iu water but are readily taken up by alcohol or ether.A substance which H ofm an a supposed to be dichloraniline was prepared by him from chlorinated isatin. He obtained it together with chlorani- line in such minute quantity that he was unable to give a definite description of its properties still less to determine its composition by an analysis. I have on this account treated the dichloraniline prepared by me with dichloride of platinum and have submitted the resulting double salt to analysis. Numbers were obtained corresponding with the formula- This platinum-salt crystallises in yellow prisms which are also readily decomposed by water with separatiou of the base. The preparation of this compound is much more easily accom- plished than that of diazo-amidobenzol. On treating au alcoholic solution of bromaniline with nitrous acid the diazo-arnidobromo- benzol separates after a short time in the form of yellow needles.They need only be once recryatallised from warm alcohol iu order to render them perfectly pure for analysis. GRIESS ON A NEW CLASS OF Diazo- amid ob romoben zol cry stallises in yellow ish-red lustrous plates or needles which are insoluble in water difficultly soluble in alcohol but very soluble in ether Diazo-aniidobrornobenzol melts at 145' C. In its deportment it exhibits the closest analogy to diazo-amidobenzol its resemblance to that body being even greater than that existing between bromaniline and aniline. I have prepared this compound from bromaniline obtained not only according to Hofm ann's method from bromisatin but also from that made from bromacetanilide as proposed by Mills.No difference could be detected between the diazo-amidobrom- benzols obtained from the bromanilines prepared according to the two different methods. Platinum-salt of Diazo-amidobromobenzol.-On mixing an alco-holic solution of diazo-amidobrombenzol with dichloride of plati-num this salt separates in the form of pale-yellow hair-like crystals which are nearly insoluble in water alcohol and ether. On the application of heat they deflagrate leaving a woolly mass of platinum and carbon. Diazo-arnidochlorobenzo1.-C H,C12N3. It is obtained from chloraniline and forms yellow needles or plates greatly resembling the preceding compound. I have only determined their melting point; it lies at 124.5' C.{C6H3(NOJ a-Diazo-amidonitrobenzol,C,,H,(N Oz)rN = C6H4W2) N2 1 The preparation of this body is also extremely simple. (NHd Alpha-nitraniline is dissolved in a moderate quantity of cold alcohol arid on passing nitrous acid into the solution the new compound separates after a short time as a yellow crystalline mass. When separated from the mother-liquor and washed with cold alcohol it is perfectly pure for analysis. The a-diazo-amido- nitrobenzol is precipitated as I have stated as a yellow crystalline mass in which no distinct form of crystallisation can be recog- nised. Generally it corisists of an agglomeration of granular or mossy microscopic particles. Even by recrystallisation from alcohol it is seldom obtained in a decided form; only once have I succeeded in obtaining yellow needle-shaped crystals whose planes exhibited a beautiful violet lustre.a-diRzo-flmiclonitrobenzol is iusoluble in water very difficultly soluble even in boiling alcohol ORGANIC COMPOUNDS ETC. and ether. It melts at 224.5"C. to a reddish-brown oil. The higher temperature it deflagrates diffusing at the same time an aromatic odour. It is an almost perfectly indifferent substance. I could not even succeed in preparing a compound with dichloride of platinum ; nitrate of silver however still gives even in very dilute alcoholic solutions a yellowish-green amorphous pre- cipitate. C6H3(N02)N2 6-Diazo-amidonitro benzd-C6H4((N0'2)(NH!2) When P-nitraniline is submitted to the action of nitrous acid almost exactly the same phenomena are observed as those which occur in the preparation of the preceding compound.The crystals which have been deposited but which in this case exhibit a per-fectly distinct form are easily purified in the same manner. The P-diazo-amidonitrohenzol differs only in a few points from the a compound. It is equally insoluble in water and appears also to be as difficultly soluble in alcohol and ether. The two substances also seem to agree in their deportment with reagents as far as could be decided by preliminary experiments. On the other hand the melting point of 6-diazo-amidonitrobenzolis 195.5' C. consequently 29' lorrer than that of a-diazo-amidonitro-benzol. The a compound crystallises as a rule in granular or moss-like shapes whilst the P-diazo-amidonitrobenzol separates already during its preparation in small though generally well- defined ruby or reddish-yellow prisms nhich by recrystallisation from alcohol or ether may be obtained of a cousiderable size.Diazo-amidgdibromobenzol.-C12H,Br4N3= C6H,Br,N {C6H3Br'2(NH'2)1 On passing a current of nitrous acid gas into a very dilute alcoholic solution of dibromaniline the diazo-amidodibromobenzol is ohtained as a bulky light-yellow precipitate. Repeated mashing with alcohol renders it perfectly pure. Diazo-amidodibromobenzol has R great tendency to crystallise in different forms. Prom alcohol and ether in which it is very difficultly soluble eyen at the boiling temperature it crystallises in fine golden-yellow interlaced needles which melt at 167'5' C.but defl7grate at a higher temperature. On allowing an alcoholic VOL. XIX. F GRIZSS ON A NEW cuss OF &ion to evaporate spontaneously yellowish-brown granules are ,requently obtained which show a golden- yellow fracture and a radiating crystalline structure. On several occasions and under conditions not accurately determined a-diazo-amidodi-bromobenzol prepared from not absolutely pure dibromaniline crystallised froin ether in extraordinarily beautiful yellow or ruby well-defined prisms. As this form differing in such a characteristic manner from the yellow needles appertained to the dihromaniline obtained from dibromisatin I should have been inclined in spite of what I had previously stated in regard to dibromaniline to seek the cause of this difference in the dibro- maniline prepared by the different methods.I soon however convinced myself that the beautiful red crystals are converted on further re-crystallisation from ether into the same golden-yellow hair-like needles. Diaxo-amialodichlorobenzo7 C ,H ,C14N = {$$$$!$ H3} is also prepared from dichloraniline and crystallises also in hair- like needles which are however distinguished from the bromine compound by their light sulphur-yellow colour. It is insoluble in water and very difficultly soluble in boiling alcohol and ether. It melts at 126*5OC. In their deportment with reagents diazo-amidodibromobenzol and diazo-amidodichlorohenzolexhibit the greatest analogy to the nitrogen-substituted aniline-derivatives already described whilst under the same conditions they yield corresponding products of decompssition.They also form precipitates with nitrate of silver. Their basic character however has completely disappeared ; they no longer give platinum-salts ; in fact they possess more the character of an acid than that of a base as they dissolve with ease in alcoholic potash forming a reddish-brown solution from which the original substance is precipitated in a perfectly unaltered state on the addition of an acid. It is how- ever not possible to prepare salts of a definite composition. Aqueous potash has no action upon these bodies. From what has been stated it is obvious that the acidifying in- fluence exerted by nitrogen when taking the place of hydrogen in aniline is repeated in an equal degree with the substitution-products of that body.OBBANIC COMPOUNDS ETC. G7 If aniline and its bromine hyponitric acid and other derivatives be arranged in the order of their basic properties there may be placed opposite to every individnal of this series a diazo double compound the basic properties of which differ from the basic properties of the corresponding aniline body by the acidifying value of one atom of nitrogen. If the diazo-amidodibromobenzol correspondingto dibromaniline already exhibited distinct acid properties it was to be expected that a body of a perfectly acid character would be obtained by the action of nitrous acid upon tribromaniline.I have instituted many experiments in order to obtain such a body but without success. Nitrous acid has not under any circumstances the slightest action upon tribromaniline. Although it was to be expected that the researches conducted with the aniline group described in the preceding pages would when repeated with bases of analogous composition lead to cor-responding results I have not omitted to prove this analogy by experiment. DIAZO=AMIDOTOLUOL.-~ {:;:;$fHJ-) 14H15N3- In order to prepare this body toluidine (amidotoluol) is dis-solved in a small quantity of strong alcohol and the solution is mixed with two or three times its volume of ether. After passing nitrous acid for a short time the originally nearly colourless solu-tion assumes a yellow colour.A drop of the solution is now taken out and evaporated on a watch-glass ; if it leaves a residue of yellow needles the operation is stopped and the mixture of alcohol and ether is allowed to evaporate spontaneously. Yellow needle-shaped crystals are deposited which must be washed with alcohol and then recrystallised from alcohol and ether. When dried over sulphuric acid and submitted to analysis they gave numbers leading to the formula Diazo-amidotoluol crystallises in yellow or reddish-yellow needles or prisms possessing a powerful lustre and corresponding in their solubility as well as in every other relation with diazo-amido-benzol. Platinum-salt of Diazo-umidotoluol,C14H~,N,.2HC1.2~tC1,.It CIBfEBS ON A NEW OLA€?43 OF is obtained in yellow glittering plates resembling iodide of lead on mixing an alcoholic solution of diazo-amidotoluol with dicblo- ride of platinum. It deflagrates at Q high temperature. DIAZO-AMIDONITRANZSOL. This body falls in small yellow crystals on pamirig nitrous acid into a dilute alcoholic solution of nitmnisidine* [amidonitraniad = C,H,(NO,) (NH,)O]. It forms microscopic yellow ueedles in- soluble in water difficultly soluble in hot ahohol and ether. When dry they are rendered highly electric by friction. They melt on the application of heat to a reddish-brown oil and defla- grate on raising the temperature. Diazo-amidonitranisol under the influence of reagents appears to undergo changes similar to those of its representatives in the aniline group.On referring once more to the most characteristic points of the nitrogen substitution-products of the hydrocarbons of the aromatic series .it will be observed that not only in their formation but also in their properties and decompositions they correspond in every relation with the peculiarities of that series of acids of which the best studied individual is diazo-amidobenzoic acid. !Phis is but natural as dl the transformations which benzoic acid and its homologues undergo under the influence of substitution processes are also effected in the hydrocarbons which in com-bination with CO form the corresponding aromatic acids. In the same measure as benzoic acid on distillation with baryta yields carbonic acid and benzol or as amidobenzoic acid splits up into carbonic acid and amidobenzol so doubtless would diazo-amidobenzol be obtained from diazo-amidobenzoic acid under similar conditions if the instability of this compound did not pre-cl ude ever j possibility of its formation under such circumstances.C7HfiOa -CO = C6H6 Benzoic acid. Ben 01. Diazo-amidobenzoic acid. * The nitraniddine was obta'ned from dinitfaaid which w prepwedarding to Cahour's method from nitranisic acid. ORGANIC COMPOUNDS ETC. The following compounds stand in the same relation :-Diazo-amidotoluylicacid. Diazo-amidotoluol. Diazo-amidonitranisic acid. Diazo-amidonit ranisol. In a preliminary note on these bodies I referred them to the type H2..) N,.This was done at a time when I knew but little of their H2 products of decomposition. If after the observations communi- cated in this paper diazo-amidobenzol for instance were still to be considered as a diamine having the formula GN?,/ Na on r-:1 endeavouring to explain the phenomena of its decompositions the same inconsistencies would become apparent as when supposing diazo-amidobenzoic acid to be constituted according to the rational -formula [ (C H,0)”HN”’J~iW2~ Hal ‘2.