DERIVATIVES OF NAPHTHACENEQUINONE. 411 XLII.--De&atives of Naphthacenequinone. BY WILLIAM HENRY BENTLEY, ARTHUR FRIEDL, FREDERICK THOMAS, and CHARLES WEIZMANK. Introduction. 1-HYDROXYNAPHTHACENEQUINONE was first prepared by the action of sulphuric and boric acids on a mixture of phthalic anhydride and a-naphthol (Deichler and Weizmann, Ber., 1903, 36, 547), the reaction proceeding in two stages with the intermediate formation of hydr- oxynaphthylbenzoic acid CO OH OH co OH CO OH I n view of the analogy existing between hydroxynaphthacenequinorie and hydroxyanthraquinone, it seemed of great interest to us to study the effect of substituent groups in both the naphthalene and the benzene nucleus of 1-hydroxynaphthacenequinone. With this object we have prepared numerous derivatives, firstly by direct substitution in 1-hydroxynaphthacenequinone itself (or in a-hydroxy-/3-naphthoylbenzoic acid), and secondly by the condensation of derivatives of phthalic anhydride with derivatives of a-naphthol.The present communication deals mainly with the hydroxy- and amino-derivatives of 1-hydroxynaphthacenequinone, and our study of *these compounds has led .us to the general conclusion that the substitu- ent auxochromic group exerts a much greater influence on the colour when in the naphthalene than when in the benzene nucleus of the naphthacenequinone molecule. This is at once apparent when the colour of the caustic alkaline solutions of the hydroxynaphthacene- quinone is observed. Thus the alkaline solution of 0 OH /\/A/\/\ \/\/\/\/ 1 I I 1 I is bluish-red 0412 BENTLEY, FRIEDL, THOMAS, AND WEIZMANN : 0 OH 0 OH 0 OH 0 OH /\/\/\/\ \/\/\/\/ and of 1 I I I I is indigo-blue.0 OH OH It would appear that in the benzene nucleus, the introduction of a hydroxyl group, instead of increasing, actually has a weakening effect on the colour of naphthacenequinone derivatives. So far as the naphthalene nucleus is concerned, the amino-group acts like the hydroxyl group in deepening the colour, but we have not yet studied its effect when substituted in the benzene nucleus. l-Aminonaphthacenequinone was found easy to prepare by the action of ammonia on 1-hydroxynaphthacenequinone a t 200’. 1-Amino-6-hydroxynaphthcccenequinone was obtained by elimination of water from aminohydroxynaphthoylbenzoic acid. The latter can be ealjily prepared by reducing the benzeneazo-derivat ive of hydroxy- naphthoylbenzoic acid : This condensation takes place with considerable ease, it being only necessary to heat the acid alone or with a solvent of high boiling point, such as nitrobenzene.When the acid is heated with concentrated sul- phuric acid the quinone formed is sulphonated, yielding a violet dye- stuff. This dye-stuff, when fused with caustic potash, yields a trihy- droxynaphthacenequinone, the amino-group being replaced by hydroxyl. 1-Hydroxynaphthacenequinone, although not affected by chlorine a t low temperatures, yields a monochloro-derivative, at temperaturesDERIVATIVES OF NAPHTHACENEQUINONE. 413 between 200° and 300°, which is probably 1 -c?b!oro-6-hydroxync6phthacene- quinone.This substance when boiled with aniline yields an anilino- derivative which dissolves in sulphuric acid, forming a reddish-yellow, fluorescent solution indicating the possible formation of an acridine derivative. Anilinoh yd?*oxynaphthncer~eq uinone forms dark brown crystals of a metallic lustre, and on treatment with acetic anhydride yields a yellow diacetyl derivative : Considerable difficulty was experienced in the nitration of 1-hydroxy- naphthacenequinone, the product usually consisting of an intimate mix- ture of nitro-compounds which could only be separated by tedious methods. The presence of boric acid, however, during the nitration led to the formation of a much simpler product, and in this way dinitrohydroxy- naphthacenequinone was seadily obtained pure.The restraining influence of boric acid is very remarkable, and is known to be of con- siderable importance in the mauufacture of alizarin derivatives. It is probably due to the formation of a boric ester. When this dinitro-corn- pound is boiled with aniline it loses one nitro-group, with the formation of the corresponding anilino-derivative : When treated with concentrated sulphuric acid, dinitrohydroxy- naphthacenequinone yields a mixture of blue and violet dye-stuffs which belong to the class 9f aminohydroxynaphthacenequinones and are similar to the componnds obtained when dinitroanthraquinone is treated with sulphuric acid. The separation and examination of these interest- ing derivativeswill be the subject of a future publication. When 3. methovyphthalic anhydride and a-naphthol are fused with boric acid condensation takes place, and l’-hydroxy-3(6)-methoxy-2-/3- naphthoylbenzoic acid (m.p. 210-215°) is produced. This acid dissolves in warm sulphuric and boric 3cid.s with elimination of water and formation of the quinone, as is seen by the deep brown colour. This colour changes, on further heating, to a reddish-violet, and the solution becomes strongly fluorescent, a change which is due to414 BENTLEY, FBIEDL, THOMAS, AND WEIZMANN : hydrolysis, to 1 : 7( 10)-dihydroxynaphthacenequinone (m. p. 280--300’) in sulphuric acid solution : co co--- MeO*C,H3<co>0 + c, OH7* OH = M e 0 C,H,<c-,,K \C,,H,*OH -+ MeO~C,,H,<~~>C,,H,.OH -& (7 or 1 0 ) H o * c , H 3 < ~ ~ > ~ , , H 5 * ~ H ( 1).I n a similar manner, 4-hydroxyphthalic acid yields 4(5) : 1’-dihydroxy- 2-P-naphthoylbenzoic acid (m. p. 215-21 6O), which condenses when heated with boric and sulphuric acids to the corresponding 1 : 8(9)-di- hydroxynaphthacenequinone : H O * C , H , < ~ ~ ~ C , ~ H ~ * O H --3 (8 or 9)HO*C,I13<~~>CloH5*OH( 1) (compare Levinsohn, “ Acides Oxynaphthoylbenzoiques,” Genbve, 1903). 4(5) : lt-Dil~ydroxy-2-P-nnphthoy26enzoic mid * is readily methylated with dimethylsulphate and caustic potash, yielding 4(5) : 1’-dirnethoxy- naphthoyZ6enxoicc ucid (m. p. 195-197”), which dissolves in warm sulphuric and boric acids with condensation and partial hydrolysis t o hydroxymethoxynaphthacenequinofie, a crystalline yellow powder melting at about 250O. These changes may probably be represented thus : 8( 9)&Ieo* C,H,<~OO>C,,H,*OH( 1).4( 5 ) : l’-Dihydroxy-2-/3-naphthoylbenzoic acid combines in alkaljne solution with diazobenzene chloride, producing a n azo-derivative which, on reduction, yields 4’-amino-1’ : 4(5)-dihydroxy-2-P-naphthoylbenzoic acid, This amino-acid easily condenses on heating alone or with nitro- benzene, or even acetic acid, with formation of aminodihydroxy- H o ’ c , H , < ~ ~ > c ~ O H ~ < ~ ~ ~ ~ ~ ’ 4’-Bromo-l’ : 4(5)-dihydroxy-2-/3-naphthoylbenzoic acid is obtained * Method of nonienclature : \/DERIVATIVES OF NAPHTHACENEQUINONE. 415 when dihydroxynaphthoylbenzoic acid is treated with bromine in the presence of carbon disulphide ; when heated with boric and sulphuric acids t o 180°, it evolves hydrogen bromide and bromine, and yields a quinone which is doubtless trihydroxynaphthacenequinone (compare Orchardson and Weizmann, Trans., 1906, 89, 215) : When 1 : 5-dihydroxynaphthalene is heated with phthalic anhydride and boric acid, it Fields 1’ : 5’-dihydroxy-2-P-naphthoylbenzoic acid (m.p. 221’), which can be readily methylated with dimethylsulphate and caustic potash with the formation of 1’ : 5’-dimethoxy-2-P- naphthoylbenzoic methyl ester. The latter on hydrolysis with caustic potash yields 1’ : 5’-dimethoxy-2-~-naphthoylbenzoic acid (m. p. 209-210O). I’ : 5’-Dihydroxy-2-P-naphthoylbenzoic acid, when heated with boric and sulphuric acids, condenses to the corresponding quinone, which at the same time becomes sulphonated, whereas 1’ : 5’-dimethoxy-2-P- naphthoylbenzoic acid, under similar treatment, condenses without sulphonation, but with the hydrolysis of one of the methoxy-groups : EXPERIMENTAL.I -A minonuphthacenequinon e. This substance is easily prepared from 1 -hydroxynaphthacene- quinone either by heating it in the autoclave with strong aqueous ammonia to 200’ for three hours, or by the action of a stream of dry ammonia gas at 200-300O. The product from either process is collected, dried, and crystallised from nitrobenzene, from which it separates in beautiful, deep-brown needles (m. p. 290-292’) : 0.151 1 gave 0,4399 CO, and 0.0502 H,O. 0.2073 ,, 9.4 C.C. at 15’ and 748 mm. N=5.30 C,,H,,O,N requires C = 79.12 ; H = 4.03 ; N = 5.13 per cent. 1 -Aminonaphthucenepuinorze dissolves easily in cold concentrated sulphuric acid with an intense bluish-red colour, and is precipitated unchanged on the addition of water, Treated with potassium C = 79.39 ; H = 3.69.416 BENTLEY, FRIEDL, 'THOMAS, AND WEIZMANN : bichrornate in acetic acid solution, it yields a yellow substance which dissolves in alcoholic potash with a red colour and is therefore possibly a diquinone. 1-Aminonaphthacenequinone is converted into an orange dye-stuff (on mordanted wool) by heating with fuming sulphuric acid.Apparently Liebermann and Kostanecki's rule (Ber., 1901, 34, 2344 ; 1902, 35, 11,490) cannot be applied to the naphthaleneqninone series, as we have already found several mordant dye-stuffs in this group which do not contain two hydroxyls in the ortho-position. .Q'-Amino- l'-hydroxy-2 -P-naphthoy 16enxoic mid, A considerable quantity of this substance was obtained by the re- duction of benzeneazohydroxynaphthoylbenzoic acid, which can be pre- pared in the following manner.1'-Hydroxynaphthoylbenzoic acid (1 85 grams) is dissolved in water (2 litres) containing caustic soda (80 grams); t o this solution (cooled to 5") is added during continuous agitation a solution of diazobenzene chloride prepared from the calculated quantity of aniline (59 grams). The sodium salt of the azo-compound separates a s a yellowish-red precipitate and is collected, ground into a paste with a little water and mixed with a solution of stannous chloride (285 grams) in con- centrated hydrochloric acid (750 c.c.). The mixture is heated on the water-bath for several hours, when the colour changes to grey.The precipitate is then collected, washed with hydrochloric acid and afterwards with water. I n order completely to remove tin com- pounds the product is dissolved in sodium carbonate, the filtered solution acidified with hydrochloric acid, and the grey precipitate col- lected and purified by crystallising from alcohol : 0.1151 gave 0.2667 CO, and 0,0425 H20. 0.2132 ,, 7.8 C.C. nitrogen at 15" and 746 mm. N = 4.20. 0.1354 ,, 0,0737 AgCl. C1= 13.47. C = 62.96 ; H = 4.10. C,,H,,O,N,HCl requires C = 62.88 ; H = 4 08 ; N = 4.08 ; C1= 10.3 4'-Amino-l'-hydroxy-2-/3-naphthoylbenzoic acid is soluble in sodium carbonate with a deep brown colour. It is only sparingly soluble in alcohol or benzene ; in hot acetic acid it dissolves, being partly ccn- verted info the quinone (see later).per cent.L)EkI\'A'l'IVES ( )F ru'A PH'L'HACENEQUINONE. 41 7 1 -Amino- 6-h ydrox ynaphthucenequinone, C,H,<~~>C,,H,(OH)*NH,. This substance is prepared by heating the foregoing acid with twenty times its weight of nitrobenzene in a reflux apparatus. As the boiling point is approached the liquid becomes dark-red and water separates. By employing only a short air condenser the water escapes, and when it has all disappeared the liquid is filtered. The filtrate on cooling deposits the 1-amino-6-hydroxynaphthacenequinone in beautiful, violet crystals possessing a green metallic lustre. The crystals are collected and freed from nitrobenzene by extracting several times with boiling benzene : 0.1310 gave 0.3572 CO, and 0.0479 H,O.C,,H,,O,N requires C = 74.74 ; H = 3.87 per cent. 1-Amino-6-hyclroxgnaphthucenequinone is almost insoluble in aqueous caustic potash, sparingly soluble in alcoholic potash with a red-violet colour. Ordinary organic solvents dissolve it only to a slight extent. It dissolves unchanged in concentrated sulphuric acid with a violet colour; hot fuming sulphuric acid converts i t into a sulphonic acid which dyes chrome- and alum-mordanted wool violet and reddish-violet respectively. When diazotised in concentrated sulphuric acid and boiled with water, dihydroxynaphthacenequinone is produced, identical with the dihydroxynaphthacenequinone described by Gabriel and Leupold (Ber., 1898, 31, 1279) and Deichler and Weizmann (BE?.., 1903, 36, 547).Furthermore, 1-amino-6-hydroxynaphthacenequinone is identical with that prepared by Deichler and Weizmann (Zoc. cit.) and Orchardson and Weizmann (Trans., 1906, 89, 121). C = 74.37 ; H = 4.07. Trihydroxy nu@ hacenequinone, C,H,<CO>C,,H,( CO OH)8. 1 - Amino-6-hydroxynaphthacenequinone is best sulphonated by heat - ing it with boric acid (1 part) and fuming sulphuric acid (3 parts of acid containing 60 per cent. of SO,) in the autoclave t o 180--185' for two hours. The product is poured into ice-water and precipitated by the addition of common salt. The crude acid dissolves in water, forming tt crimson-red solution with a violet tint. We were unable t.0 isolate the acid in a sufficiently pure state for analysis. When fused with caustic potash, it yields trihydroxynaphthacenequinone. The fusion is carried out in a nickel crucible (1 part of acid, 38 parts of caustic potash) at 200--250' until the violet colour of the aqueous solution changes t o a pure red.The product is dissolved in water, acidified with hydro-418 BENTLEY, FRIEDL, THOMAS, AND WEIZMANN : chloric acid, the brown, flocculent precipitate collected, washed with water, dried, and crystallised from nitrobenzene, from which it separates in deep-brown crystals with a green metallic lustre : 0.1522 gave 0.3932 CO, and 0.0405 H,O. C,,H,,O, requires C = 70.6 ; H = 3.2 per cent. ~ri?Lydrox~ncc;PILt7LaCenequino?ae is very sparingly soluble in organic solvents; it dissolves in concentrated sulphuric acid with a red colour, in aqueous caustic potash with a beautiful pure red shade recalling that of purpurin; the colour fades when the alkaline solution is allowed to stand.It dissolves sparingly in a solution of alum, pro- ducing a rose-coloured, fluorescent solution. C = 70.5 ; H = 2.9. 1 -Chloro-6-hydroxy~zap?~tJ~cccenequinone, C,H,<CO>CloH,Cl* co OH (a). As stated in the introduction, 1-hydroxynaphthacenequinone is only attacked by chlorine a t a high temperature, and we have found chlorination is conveniently effected in the following manner. 1 -Hydroxynaphthacenequinone is loosely packed in a combustion tube, heated in a furnace to a temperature not exceeding 300°, and a current of dry chlorine.is passed through the tube. The course of the reaction is easily followed by observing the partial fusion of the product, and when the whole of it is pasty it is removed from the tube and crystallised from nitrobenzene, from which it separates in brown needles, but after further recrystallisation with the aid of animal charcoal it is obtained in pale yellow needles melting at) 290-293' : 0,1668 gave 0,0794 AgCl.C1= 11.67. Cl,H90,C1 requires C1= 11.50 per cent. 1 -ChZoro-6-?~ydro~ync~p?~th~cenepuinone is soluble in hot nitrobenzene or acetic acid, but sparingly so in hot alcohol or benzene. It dissolves in concentrated sulphuric acid with a n intense red colour. Aqueous caustic potash scarcely dissolves it, but it is soluble in alcoholic potash with a red colour. Cfr,Zoroacetoxyn~~I~t?~acenepuino~~e, c,H,<~~>c~,H,c~~oA~, co results when the foregoing substance is boiled with acetic anhydride and a little zinc chloride until solution is complete.The product is poured into water and the light yellow precipitate collected, washed with water, dried, and crystallised from nitrobenzene or acetic acid, in which latter it is only sparingly soluble. It melts a t 270--273° and is hydrolysed by boiling with aqueous caustic potash or concentrated sulphuric acid.DERIVATIVES OF NAPI-ITHACENEQUINONE. 419 1 - Anilino-6-hydi*oxynapl~thacenequinone, This derivative is readily produced by boiling chlorohydroxy- naphthacenequinone with five times its weight of aniline for an hour. On cooling, and especially on the addition of alcohol, the product separates in beautiful, deep brown crystals with a metallic lustre : 0.1084 give 0.3131 CO, and 0.0430 H,O.0.1862 ,, 7.0 C.C. nitrogen at 16' and 764 mm. N = 4.40. C2,H,,0,N requires C = 78.90 ; H = 4-11 ; N = 3.84 per cent. Anilinohydroxynaphthacenequinone is sparingly soluble in alcohol or acetic acid, readily so in hot aniline or nitrobenzene. Its solution in alcoholic potash is deep blue-violet, and sulphuric acid dissolves it, forming a red solution, which, on heating, becomes reddish- yellow and fluorescent, doubtless owing to the formation of an acridine derivative. When boiled with acetic anhydride and a little zinc chloride, the colour changes t o yellow and acetnnilinoacetoxynaphthacene- C = 78.77 ; H = 4.33. quinone, C,H,<CO>Cl,H,(OAc)-hTAcPh co is produced. The product is poured into water, collected, washed with water, dried, and crystal- lised from acetic acid : 0.1747 gave 0.4756 CO, and 0.0655 H,O.0,1371 ,, 4.2 C.C. nitrogen at 15' and 736 mm. N = 3.52. C = 74.3 ; H = 4.17. C,,H1,O,N requires C = 74.83 ; H = 4.23 ; N = 3.12 per cent. Binitrohydrox ynaphthacenequinone, U,H,<~~>Cl,H,(OH)(NO,), [NO, : NO, = 2 : 6 13. To prepare this substance, 1-hydroxynaphthacenequinone is dis - solved with an equal part of boric acid in concentrated sulphuric acid and treated with an excess of nitric acid, the temperature of the mix- ture being kept below 5". The product is poured into water, the pre- cipitate collected, washed with water, dried, and purified by crystal- lising from nitrobenzene, from which it separates in reddish-brown crys- tals melting a t 275O : 0.1185 gave 0.2538 CO, and 0.0310 H,O.0.1198 ,, 7.5 C.C. nitrogen a t 21.5" and 762 mm. N = 7.13. C1,H,O,N, requires C = 59.34 ; H = 2.1 7 ; N = 7.69 per cent. Dinitrohydi*oxynaphthacenepuinone dissolves in warm sulphuric acid with a brownish-yellow colour; it gives with caustic soda a blue sodium salt which is sparingly soluble in water. C =58*17 ; H= 2.90.420 BENTLEY, FRIEDL, THOMAS, AND WEIZMANN : When boiled for a few iiiiuutes with acetic: anhydride and a little zinc chloride, i t yields dinitroacetoxynaphtl~acenequinone, c~H~<~~>c~,,H,(No,)~.os~. This is obtained pure by pouring the prorlrict into water, collecting the precipitate, washing, drying, and cryst~llising from acetic acid, from which it separates iri yellow crystals melting a t 276-278" with effervescence : 0.1026 gave 0.2310 CO, and 0.0269 H20.0.1206 ,, 7.8 C.C. nitrogen at 15" and 756 mm. N = 7.5. C = 5 8 m ; H = 3.83. C,,H,,O,N, requires C = 59.1 1 ; H = 2.46 ; N = 6.90 per cent. It is sparingly soluble in alcohol or benzene. it dissolves with a yellowish-red colour. I n warm sulphuric acid Mononitromilinoh yd?*oxynapT~thacenequinone, This derivative is obtained by boiling dinitrohydroxynaphthacene- quinone with aniline until the red colour of the solution has changed to a bluish-violet. On cooling, it separates in black crystals with a metallic lustre, and is purifjed by recrystallising from aniline : 0.1 322 gave 0.3416 CO, and 0.0492 R,O. 0.1819 ,, 10.5 C.C. pitrogen a t 14" and 754 mm. N = 6 * 8 5 . C,,H,,O,N, requires C = 70.24 ; H = 3.41 ; N = 6.83 per cent.Mononitroccz~ilinoT~yd~oxyn~phtT~~cenequinone dissolves in sulph- uric acid with an intense violet colour. It is insoluble i n aqueous caustic potash, but dissolves in alcoholic potash, yielding an intense blue solution. C = 70.47 ; H = 3.38. 1 '-Hydroxy - 3 (6)-methox y- 2-P-?taphthoyl6enxoic Acid, (3 or 6)MeO*C,H,<~~2W~C,,H,.OH. This acid is produced by heating 3-inethoxyphthalic anhydride (5 grams) and boric acid (15 grams) in a porcelain dish until partial fusion takes place, then, after finely powdering the mass, mixing with a-naphthol (4 grams) and boric acid (10 grams) and reheating to 190-195" for about an hour. The fused product is poured into water and extracted several times with boiling water to remove boric acid. The residue is boiled with sodium carbonate and animal charcoal, the liquid filtered and acidified with hydrochloric acid, when 1'-hydroxy- 3( 6 j-met hoxy-2-P-naphthoylbenzoic acid is precipitated in yellow flocks.This acid is purified by crystallising from alcohol or benzene :DERIVATIVES OF NAPHTHACENEQUINONE. 421 0,1246 gave 0.3238 CO, and 0.0510 H,O. c'=70*88; H=4*55. C19H1405 requires C = 70.81 ; H = 4*35 per cent. It melts at 210-215° and is readily soiuble in acetone or acetic acid. 1 : 7(10> -Di?bydroxpnupJAt?mcenequinone, 0 OH H O 0 O H The acid just described dissolves in concentrated snlphuric acid with a brown colour, which on heating changes t o a beautiful reddish-violet. When the intensity of the colour is at its maximum the product is poured into water, the precipitate filtered, washed with sodium carban- ate and water, dried, and crystallised from nitrobenzene : 0.1221 gave 0.3320 CO, and 0.0426 H,O.C:sHloO, requires C = 74.48 ; H = 3.45. 1 : 7( 10)-Dihydrox~nu~~~t~~c~c~nequinone melts indehitely at 280-300", and is soluble in concentrated sulphuric acid, forming a reddish-violet, fluorescent solution. I t is sparingly soluble in aqueous caustic potash and in hot sodium carbonate solution, but dissolves in alcoholic potash with a red colour. It is also soluble in acetic acid, nitrobenzene, or hot alcohol. C=74*16; H=3.88. 4(5) : I'-Dil~ydrox~-~-P-naiv?~t~oy/lbeizxoic Acid. The preparation of this acid from 4-liydroxyphthalic acid is carried out in exactly the same manner a s that just described in the case of hydroxymethoxynaphthoylbenzoic acid (p.420). The crude acid is purified by crystallising from alcohol or acetic acid : 0.1 183 gave 0.3031 CO, and 0.0460 H,O. C,,H,,O, requires C = 70.13 ; H = 3.89 per cent. 4(5) : 1'-Dihydroxy-2-P-nap?tthoylbensoic acid melts a t 2 15-2 16", and is solublein alcohol, benzene, or acetic acid ; i t dissolves in alkalis with a yellow colour. C = 69.87 ; H = 4.32. 4(5) : l ' - ~ i n a e l ~ o x y - 2 - ~ - n a p ~ t l ~ o y Z ~ e n x o i c Acid. When dihydroxynaphthoylbenzoic acid is dissolved in methyl alcohol and shaken with a large excess of dimethyl sulphate and sufficient caustic potash t o maintain a slight alkalinity, the methyl ester o€ 4(5) : lf-dimethoxy-2-P-naphthoylmethoxybenzoic acid is formed and separates, when the above alcoholic solution is diluted with water, as a heavy oil which slowly solidifies.This ester, when boiled with VOL XCI. F F422 BENTLEY, FRIEDL, THOMAS, AND WEIZMANN : alcoholic potash and poured into dilute hyd?ochloric acid, yields the corresponding acid which crystallises from methyl alcohol in colourless needles melting a t 195-197O : 0.1704 gave 0.4455 CO, and 0.0728 H,O. C,,H,,O, requires C = 71.43 ; H = 4.76 per cent. 4(5) : l'-Dimethoxy-2-/3-naphthoylbenxoic acid dissolves in alcohol, benzene, or acetic acid ; its solution in aqueous sodium carbonate has a faint yellow colour. C = 71.30 ; H= 4.75. 1 : 8 (9) -D ih ydvoxymaphthacmegzcinone. This substance is prepared by heating dihydroxynaphthoylbenzoic acid with boric acid (1 part) and concentrated sulphuric acid (10 parts) at 140'.The colour becomes intensely red, and when no further change is observed, the product is cooled, poured into water and the precipitate collected, mashed with sodium carbonate, then with water, dried, and crystallised from nitrobenzene. It forms yellowish-red needles which do not melt at 330° : 0,1125 gave 0.3070 CO, and 0.0377 R,O. 1 : 8( 9)-Di~ydl.oxynapht?~ace~~e~z~inopze is soluble in hot nitrobenzene or acetic acid, sparingly so in alcohol or benzene. It gives yellowish-red solutions with aqueous sodium carbonate or caustic potash. When heated on the water-bath with acetic anhydride and a little zinc chloride it is converted into C= 74.4 ; H= 3.7. C,8H,o0, requires C = 74-48 ; H = 3.45 per cent. 1 : 8(9)-Dincetoxynaphthacenequinone, This compound is isolated by precipitation and washing with water, drying, and crystallising from acetic acid, from which it separates in pale yellow needles melting a t 227-228' : 0.1320 gave 0.3415 CO, and 0.0445 H20.02,H1406 requires C = 70.60 ; H = 3.74 per cent. This substance is soluble in alcohol or benzene and dissolves in concentrated sulphuric acid (with hydrolysis), giving a reddish-violet solution ; in cold aqueous caustic potash i t is insolubie, but when heated it undergoes hydrolysis and dissolves with a yellowish-red colour. On treating with concentrated nitric acid it dissolves, and on dilution with water a crystalline nitro-compound separates, C = 70.53 ; H = 3.71.bERlVATIVES OF NAPETTHACZNEQUINONE. 423 l-Hpdroxy-8(9 )-methoxynaphthacenepuinone, When dimethoxynaphthoylbenzoic acid is dissolved with boric acid in sulphuric acid on the water-bath, condensation takes place, the colour becoming reddish-violet.The quinone is isolated and purified in the same manner as dihydroxynaphthacenequinone (p. 422). It forms a crystalline, pale yellow powder melting indefinitely a t 250" : C = 74.82 ; H=4.33. CJ9H1,0, requires C = 75.00 ; H = 3.95 per cent. 0.1220 gave 0,3347 CO, and 0,0476 H,O. , It is sparingly soluble in hot alcohol, acetic acid, or benzene, soluble in alcoholic potash with a cherry red colour ; with aqueous caustic potash it forms an almost insoluble red salt which resembles that of monohydroxynaphthacenequinone. I n cold concentrated sulphuric acid it dissolves with a reddish-violet colour, which on heating above 100" changes t o red, indicating hydrolysis of the methoxy- group : $'-An~ino-l ; 4(5 )-dihydroxy-2 -P-ncci~3l~tho?lEbenxoic Acid.This acid is prepared by combining diazobenzene chloride with dihydroxynaphthoyl benzoic acid and reducing the azo-derivative so formed with stannous chloride and hydrochloric acid. The method OF procedure is exactly the same as that given for aminohydroxy- naphthoylbenzoic acid (p. 416). It is purified by dissolving in aqueous sodium carbonate and precipitating with hydrochloric acid. It is sparingly soluble in alcohol, benzene, or light petroleum ; in sodium carbonate solution i t dissolves with a deep yellow colour : 0.1188 gave 0.3909 CO, and 0.0457 H,O. 0.1997 ,, 7.3 C.C. nitrogen a t 17' and 770 mm. N=4*37.Cl,Hl,05K requires C = 66.S7 ; H = 4 04 ; N = 4.33 per cent. When heated alone or in acetic acid or nitrobenzene this acid under- goes condensation, with the elimination of water and formation of C: = 66-78 ; H = 4.27. 1 -Amino- 6 ; 8(9)-dil~yclroxynapT~tl~acenequinone. The method of preparation of this substance is exactly similar to that described in the case of (l)-amino-6 -hydroxynaphthacenequinone (p. 417). This aminodi~ydroxynapT~thuce?zequinonne dissolves in cold sulphuric acid with an intense bluish-red colour and in alcoholic potash with a reddish-blue colour. It is readily oxidised by potassium dichromate in acetic acid solution : F E ' 2424 BENTLEY, FRIEDT,, THOMAS, AND WEIZMAKN : 0.1 185 gave 0.3058 CO, and 0.0427 H20. 0.1673 ,, 7.2 C.C. nitrogen at 15" and 744 mm.N = 5.01. c' = 70.37 ; H = 4.0. C18Hl10,N requires C = 70.8 ; H = 3.6 ; N = 4.6 per cent'. 6' (?)-Brorno- 1' : 4(5)-dil~yli*ox9 "-P-?lcrl)l~(l~oyZbenxoic Acid. This derivative is obtained when an excess of bromine is added to di- hydroxynaphthoylbenzoic acid suspended in carbon disulphide and the mixture gently warmed on the water-bath for two hours. The carbon disulphide and the excess of bromine are then allowed to evaporate spontaneously and the solid residue crystallised from acetic acid, from which it separates in needles melting at 270" with decomposition : 0.1467 gave 0.2996 CO, and 0.0403 H,O. C =55*70 ; H= 3.05. 0.1888 ,, 0.0938 AgBr. Br=21.13. Cl,HllO,Br requires C = 55.81 ; H = 2.S4 ; Br = 20.67 per cent. This acid is sparingly soluble in alcohol or benzene, readily so in hot acetic acid.It dissolves in sodium carbonate with a deep yellow colour. When heated with boric acid in concentrated sulphuric acid to 180" condensation occurs and a t the same time hydrogen bromide and bromine are evolved and a trihpdroxynaphthacenequinone, is produced. This quinone was isolated and purified in the usual manner and obtained as a brown, crystalline powder. We were, how- ever, unable to obtain it quite pure, as even after several recrystallisations it still contained traces of bromine. 1' : 5' - ~ ~ ~ ~ y d r o x y - 2 - ~ - n c ~ p ? ~ t ~ ~ o ~ ~ b e n x o ~ c Acid. This acid is best prepared in the followingmanner. Phthalic anhydride (20 grams) and boric acid (50 grams) are partly fused in a porcelain basin, then powdered and mixed with 1 :5-dihydroxy- naphthalene (20 grams) and heated to 200" for three hours.The pro- duct is extracted with boiling water until free from boric acid and the residue boiled with sodium carbonate, filtered, and acidified with hydro- chloric acid. The brown, resinous precipitate is collected, boiled with wat,er and calcium carbonate, the solution of the calcium salt filtered, and the acid reprecipitated by the addition of hydrochloric acid. The precipitated acid is collected and purified by crystallising from acetic acid : 0.1069 gave 0.2732 CO, and 0,0395 H,O. 1' : fi'-Dil~ydi.ox~-a-p-ncc;ul~tl~oyZ~enzoic acid melts at 2 2 lo and is C = 69.70 ; H = 4-11. C18H1205 requires C = 70.13 ; H = 3.89 per cent.DERIVATIVES OF NAPHTHACENEQUINONE.425 soluble in alcohol, acetone, or acetic acid. I n sodium carbonate solution it dissolves with a deep yellow colour. 1’ : 5‘- Diniethoxy-2-P-naphthoylbenzoic Acid.--When the acid just, described is dissolved in alcohol and shaken a t 20-25O with excess of dimethyl sulphate and sufficient aqueous caustic potash to .render the solution distinctly alkaline, the methyl ester of dimethoxynaphthoyl- benzoic acid is obtained, on dilution with water, as an oil which gradually crystallises. This oil, when boiled with alcoholi9 potash and poured into dilute hydrochloric acid, yields dimethoxynaBhthoylbenzoic acid as a white precipitate, which is collected and purified by crystal- lising from acetic acid : 0.1810 gave 0,4737 CO, and 0.0780 H20. 1’ : 5’- Dimethoxy-2-~-naphthoyZbe~~xoic acid melts at 209-2 1 O”, and dissolves in alkalis with a pale yellow colour. It dissolves incold con- centrated sulphuric acid with a brown colour, which on heating changes to green, indicating the formation of C=71*38; H = 4.79. C,oHI,O, requires C = 71.4 ; H = 4.8 per cent.5 : 1 -Hydrozy-5-metlho.xyncc2,iLt haceneqziinone. This quinone is isolated from the green sulphuric acid solution by precipitating with water, collecting, drying, and cry stallising from nitrobenzene : 0.1960 gave 0.5383 CO, and 0,0704 H20. U,,H,,O, requires C = 75.0 ; H = 3.9 per cent. 1 -Hydroxy-5-rnethoxynaphtJ~ncenequinone crystallises in red needles, and dissolves in alcoholic potash with a red, in concentrated sulphuric acid with a green, colour. The latter changes on heating to blue, owing t o the hydrolysis of the methoxy-group.The quinone is soluble in acetic acid or nitrobenzene, sparingly so in alcohol or benzene. C = 74.91 ; H = 3.99. 1 : 5-Dihydrox?/naphthccce?Eepuilzolze-4 3-sulphonic Acid. 1’ : 5’-Dimethoxy-2-/3-naphthoylbenzoic acid differs from the corre- sponding dihydroxy-acid in its behaviour when warmed with boric and sulphuric acids. The dimethoxy-acid is condensed to the quirione with- out sulphonation, but the dihydroxy-acid yields 1 : 5-dihydroxynaphtha- ceneyuinonesulphonic acid, which is precipitated on dilution with water. Purified by crystallising from dilute alcohol, it is obtained RS a red, crystalline powder : 0.1028 gave 0.2277 CO, and 0.0397 H,O. 0.1805 ,, 0.1092 BaSO,. S= 8.31. (2 = 60.41 ; H = 4-29.C,,H,,07S requires C = 58.38 ; H = 2.70 ; S.= 8-65 per cent.426 BENTLEY, FRIEDL, THOMAS, AND WEIZMANN : The acid dissolves in alkalis and in sulphuric acid with a violet-blue It dyes wool a colour. It is soluble in water, sparingly so in alcohol. reddish-yellow shade, and has some affinity for cotton. THE UNIVERSIT%-, &fASCIIlC3l’ER. Addendum b p E. C. C. BALY and W. B. TUCK. The absorption curves of these compounds are shown in Figs. 1-15, the full curve in each case being that obtained with a solution FIGS. 1 and 2. Oscillation f r e p e n cic,~. 16 18200022 24 26 28bOOO 32 34 36 38400042 1 4 of the compound in alcohol, the clotted curve being obtained after the addition of excess of sodium ethoxide, whilst the dot and dash curve isDERIVATIVES OF NAPHTHACENEQUINONE.427 that obtained with a solution in concentrated sulphuric acid containing about 3 per cent. of boric acid. I n each case N/lO,OOO solutions were employed and the curves drawn by plotting the logarithms of tho thicknesses of the solution used against the limits of absorption, FIG. 4. Oscillation frequencies. 0 0 0 1 ; 8(9)-Dihydrox2/?aaphthneenequi?lone. In Fig. 1 are shown the three curves of 1-hydroxynaphthacenequinone, which establish the type of absorption exhibited by all the com- pounds described in the paper; the full and dotted curves, repre-428 BEN‘I’LEY, FRIEDL, THOMAS, AND WEIZMANN : senting the absorption of 1-hydroxynaphthacenequinone in neutral and a1 kaline alcoholic solutions respectively, show the existence of two 0 0 FIG.5. Osc illn t i o n f rcqzmcies. 14 16 18200022 24 26 28300032 36 36 38400042 44 absorption bands, one in the ultra-violet due to the presence of a certain amount of benzenoid tautomerism and the other, due to isorropesis, in FIG. 6. Oscilln,lioiiJ fmpzccncics. 0 0 16 18 200022 24 26 28300032 34 36 38400042 44 8 2 5 20 IT: 18 2 22 7-l Rydroxy-5 -1nethoxynaphl haccncpinonc. the visible part of the spectrum. It will be noticed that in Fig. 1, and indeed in all the substances examined, the latter absorption band is nearer to the red when the solution is alkaline. This fact, coupledDERIVATIVES OF NAPHTHACENEQUINONE. 429 with the fact that the diacetoxynaphthacenequinone (Fig. S) exhibits only very short absorption bands, shows the isorropesis is not simply FIG.7. OscillatioiL f raqzmcies. 0' r!- 22 R one of a quinonoid type between the two carbonyl groups; it is manifest that the process of isorropesis is in some way connected with FIG. 8. Oscillat ioii freqicencics. 1 4 16 18200022 24 26 28 300032 34 36 38400042 44 0 the presence of the hydroxyl groups in close proximity to the carbonyl groups. It has been pointed out (Baly and Ewbank, Trans., 1905,430 BENTLEY, FRIEDL, THOMAS, AND WElZMANN : 87, 1347) that the absorption band of the phenols is shifted towards the red in alkaline solution, this being also true for the aminophenols ; it Fro. 9. Osc iltccl i o ~ frcqzicncics. 16 18 2000'22 24 26 28300032 3.1 36 38 400042 44 0 0 l-4 0, $ % E + - 5 2 ' 0 s h Y 1 -A! mino- 6 -hydroxynnph th accncqzcinon c.is probable that in this fact is to be found the explanation of the shift of the isorropesis band of the paphthacenequinone derivatives in F ~ G . 10. Oscillation freqiscn cies. 16 18200022 24 26 28300032 34 36 38400042 44 1 -Amino- 6 : 8 (9) -dih ytlroxync/,p?( Ih ncc?zeqwh om. alkaline solution, for this band is no doubt due in some way to the phenolic groupings, and any change of frequency in the absorption bandDERIVATIVES OF NAPHTHACENEQUINONE. 431 produced by the action of alkali on the latter will produce a pro rrctn change in the former. FIG. 11. Oscillntioit frcqzccmies. The absorption spectra show very clearly the different effect obtained by substitution of hydroxyl groups in the naphthalene and E FIG. 12. Oscillation frcpzccizcics. 14 16 18200022 24 26 28300032 34 36 38400042 44 the benzene nuclei.The following table shows the position of the heads of the absorption bands and their relative persistence. By the persistencu of an absorption band is meant the relative change of432 BENTLEY, FRIEDI,, THOMAS, AND WElZMANN : dilution over which the band persistp, and this value may be taken as a measure of the process taking place which gives rise to the ’;. 10 FIG. 13. Oscillnt ioiL frcqticitcics. 1 6 18200022 24 26 28300032 34 36 38400042 44 absorption. The persistence of each band is measured by the distance it extends over the ordinates on the diagrams. FIG. 14. Oscillation f requci LcieS. 8 14 16 182G0022 24 26 28300032 34 36 38400042 44 3 2 1 - Ch 7oro-6-h~droxynnphthncene~~~i~~one. Comparing monohydroxyizaphthacenequinone with the 1 : 6-di- hydroxy-derivative in which both hydroxyl groups are in the naph-DERLVATIVES OF NL4PHTHACEWEQUINONE. 433 thalene residue, it will be seen that in neutral solutions the head of the band has shifted from 9200 to 2050 and in alkaline solution from 1900 to 1800, whilst the persistence has increased from 5 to 6 in the one case and from 3.5 to 5.5 in the other.It is thus evident that the introduction of a second hydroxyl in position 6 both shifts the absorption towards the red and at the same time materially increases the amount of the isorropesis. On the other hand, the introduction of a second hydroxyl group in the benzene residue has the opposite effect ; in neutral solution the absorption band is shifted a very little to the red, but in alkaline solution the band is shifted towards the blue.I n both the 1 : 7- and the 1 : 8-dihydroxy-compounds the per- sistence is less than in the monohydroxg-compound ; especially is this FIG. 15. 0scillat;on fiepzwncics. the case in the 1 :&compound. That this phenomenon is not peculiar to the benzene residue is shown by the trihydroxy-compound (1 : 2 : 6 ?), where the absorption band in both alkaline and neutral solution is nearer the blue, and the persistence less than in the monohydroxy-compound, proving that the third hydroxyl group more than counteracts the influence of the second, making the coinpound less coloured than the monohydroxy-compound. I n Figs. 6 and 7 are shown the curves of the 1-hydroxy-5- and -8-methoxy-compounds, and in Fig.8 those of the 1 : 8-diacetoxy- compound, which show the great effect produced by acetylatiog the two free hydroxyl groups. The relative position of the amino- and hydroxyl-groups has very much the same effect as that just ascribed to the hydroxyl groups434 DERIVATIVES OF NAPHTHACENEQU'INONE. alone. The followiiig table gives the measurements from the absorp. tioii curves of the three aminohydroxy-derivatives described in the paper. It will be noticed that the isorropesis bands tend to subdivide at the heads into two or three narrow bands ; this, however, does not influence the meitsurenmnts, which are purely comlma.tive : T A ~ L ~ S r. Head of band in oscillation Compound. Solvent. frequencies. Persistence. Mono1iydroxyiial)lithaceIieqiii~ioiie . . . . . . . . . Alcohol 3200 5 1 : 6-Dihyciroxynaplithaceiiequiiione.. . , . . , . . Alcohol 2050 6 Alkali 1900 3 -5 Su1l)huric acid 1750 6 Alkali lS00 5.5 1 : 7-Dihydroxynaplitliaceiiequinone.. . . . . . . . Alcohol .2100* 4.5 Alkali 2050 3 1630 Snl1)lii~ric acid -, lf50 , 7 1 : 8-Dihydroxynaphtliacenequinone.. . . . . . . . Alcohol ' 2200 ' 2.5 Alkali { iyi:] 3 Siildiiiric acid 1750 7 1 : 2 : 6(?)-TriliyclrosyiiaphthsLce1ieqiii11oii~~ . Alcohol 2050 4'5 Sulphuric acid 1750 4-5 Alkali 1950 3.5 TABLE 11. Compouiid. 1 -An1ino-6-hydroxynaph thaceneyuinoiie . . . . . . , . . . . . 1-Amino-6 : 8-dihydroxynni)2itli~i~~iie~i~iiiione . . . . . , Head Solvent. of bands. Alcohol { ;:::} 2080 Alkali l7SO Sulp,huric { 18tO } acid 1 O i O 1800 Alcohol { 1950} 21 00 Alkali 1700 acid 1750 Sul phuric I'er- sistence. 7'5 6 5 ' 5 5 4 5 l-Anilino-6-l-iydroxyiia~~~itli:lce11eqiiiii~ne . . . . . ... . . . Alcohol 1900 4 Alkali { t;::} 5.5 acid 1800 CI K Sulphuric The introduction of the second hydroxyl group in position 8, although it does not materially alter the position of the bands, very considerably decreases the persistence ; the same is true when the hydrogen of the amino-group is replaced by the electro-negative phenyl group. The influence of methylating the hydroxyl groups is shown by thePERKIN: CONSTITUENTS OF NATURAL INDIQO. PART 11. 435 curves in Pigs. 6 and 7, whilst the curves obtained with the 1 :€i-dihydroxysulphonic acid compound are shown in Fig. 12. In Figs. 13-15 the effect of the substitution by chlorine and by the nitro-group is shown. The influence of this substitution is very considerably to reduce the persistence of the bands ; the 1 -hydroxy- 2 : 6-dinitro-compound was found to be so slightly soluble in sulphuric acid as to render the observation of its absorption impossible in this solvent. SPECTROSCOPIC LABOKATORY, UNIVERSITY COLLEGE, LONDON.