NAPHTFIOYLBENZOIC ACID AND NAPHTHACENEQUINONE. 115 XIJ I.-Some Derivatives o j Xaphthoylbenxoic Acid and of Naphthacenequinone. By JAN QUILLER ORCHARDSON and CEARLES WEIZNANN. H H H H Nc6phthacene, H H H H and n,aphthacenequi?zone, H O H H were first prepared from ethindiphthalide by Gabriel and Leupold (Ber., 1898, 31, 1279)) and subsequently Deichlers and Weizmann (Bey., 1903, 36, 547) obtained (1)-hydroxynaphthacenequinone by the action of sulphuric and boric acids on a mixture of phthalic anhydride and a-naphthol : 1 2116 ORCHARDSON AND WEIZMANN : SOME DERlVATIVES OF By melting phthalic anhydride with a-naphthol and boric acid alone they obtained (1)-hydroxynaphthoylbenzoic acid, and found that this acid is evidently an intermediate product in the formation of (1)-hydroxynaphthacenequinone by the above-mentioned process, since when heated with sulphuric and boric acids it is con- verted into this substance.I n the following experiments, we have sought to make various derivatives of (1)-hydroxynaphthoylbenzoic acid, and with their aid to obtain the corresponding derivatives of naphthacenequinone, this indirect method being necessary on account of the difficulty of obtain- ing pure products by direct substitution in naphthacenequinone itself. We met, however, in the course of the experiments, with greater difficulty than we had anticipated, owing to the facility with which most of the substituent groups are eliminated when the attempt is made t o condense the derivatives of naphthoylbenzoic acid to the corresponding naphthacenequinones by means of concentrated sulphuric acid.During the preparation of (1)-chloronaphthoylbenzoic acid by the action of phosphorus pentachloride on (1)-hydroxynaphthoylbenzoic acid (Proc., 1904, 20, ZZO), we had previously noticed the formation of a red substance insoluble in caustic potash. By a modificat:ion of the experimental conditions this was ultimately obtained as the chief product of the reaction, and we find that it is evidently a monochloro- co naphthacenequinone, C,H,<co>C,oH,C1, and isomeric with that pre- pared by Pickles and Weizmann (Proc., 1904, 20, 220). is converted into phenylaminonaphthacenequinone, The new monochloronaphthacenequinone, when digested with aniline, We next found that (1)-hydroxybromonaphthoylbenzoic acid, UGH4<gE2fZ\C10Hfi <z:i:j ’ was very readily prepared by the action of bromine on (1)-hydroxy- naphthoylbenzoic acid, and the corresponding (1) -hydroxybromonaphth- acenequinone, CGH4<Eg> C,0H4<i:g)), was obtained from this by the action of concentrated sulphuric acid, although considerable decomposition occurred during the reaction.The position of theNAPHTHOYLBENZOIC ACID AND OF NAPHTHACENEQUINONE. 117 bromine is not yet known wit.h certainty, but as the substance does not form an azo-compound with diazobenzene chloride, whereas the (1)-hydroxynaphthoylbenzoic acid does, it is probable that the bromine occupies the position (6) indicated in the above formula. Considerable difficulty was experienced in obtaining a monochloro- but we ultimately obtained a good yield of the acid by treating (1)-hydroxy- bromonaphthoylbenzoic acid with phosphorus pentachloride in the presence of benzene.I n attempting to prepare nitro- and amino-derivatives of naphth- acenequinone, we found that the action of nitric acid on naphthacene- quinone did not give satisfactory results owing to the difficulty of separating the various products of the reaction. Again, (1 )-hydroxy- naphthoylbenzoic acid is decomposed by the action of nitric acid ; we therefore first methylated it, and on treating the methyl ester of the methoxynaphthoylbenzoic acid thus formed with nitric acid, a good yield of the mononitro-compound was obtained, which, on hydrolysis, yielded 1 -hydroxynitronaphthoylbenzoic acid : monobromonaphthoylbenzoic acid, C,H4<C0,H\Cl,H,<~r, co - We were unable to obtain the hydroxynitronaphthacenequinone corresponding to this acid by the action of sulphuric acid, and there- fore proceeded to reduce it with zinc and acetic acid.It was interest- ing to find that by this means, instead of obtaining 1-hydroxyamino- naphthoyl benzoic acid, condensation occurred simultaneously with reduction and yielded 1 -hydroxyaminonaphthacenequinone, Experiments are at present in progress which we hope will clearly demonstrate the positions of the nitro- and amino-groups in the com- pounds mentioned above, and the results of which will be published shortly. EXPERIMENTAL. Mortochloronaphthacenepuinone. I n order to prepare this substance perfectly dry, (1)-hydroxy- naphthoylbenzoic acid (40 grams) was mixed with benzene (200 c.c.) and a considerable excess of phosphorus pentachloride (80 grams) was added gradually in such a way that the reaction was kept well under118 ORCHARDSON AND WEIZMANN : SOME DERIVATIVES OF control.The whole was then heated on the boiling water-bath with a reflux condenser until no further evolution of hydrogen chloride occurred. The benzene was next distilled off over a free flame (not from the water-bath), and when most of the solvent had passed over, a brisk reaction again set in, with further evolution of hydrogen chloride, and the contents of the flask assumed a deep red colour. Water was added to decompose phosphorus oxychloride and pentachloride, the solid was collected at the pump, digested with caustic potash, washed, and dried.It was then recrystallised from nitrobenzene, from which it separated in bright red needles, which retained their colour after repeated crystallisation in presence of animal charcoal. 0.1790 gave 0-4810 CO, and 0.0582 H,O. C = 73.3 ; H = 3.6. C,,H,O,CI requires C = 73.3 ; H = 3.1 ; C1= 12.1 per cent. This monochloronaphthacenequinone melts a t 254O, and is therefore isomeric with the yellow compound obtained by the action of sulphuric acid on 1-chloronaphthoylbenzoic acid (Pickles and Weizmann, Proc., 1904, 20, 220). Phenylacminonaphthacenequinone was obtained from the above chloronaphthacenequinone by boiling it for two hours with just sufficient aniline to dissolve it. On cooling, the substance separ- ated in red leaves melting a t 245'. 0.1698 ,, 0.0768 AgC1.C1= 11.2. 0.1 120 gave 0.3379 CO, and 0.0472 H20. C = 82.2 ; H = 4.7. 0.2108 ,, 7.6 C.C. nitrogen at 18' and 756 mm. N=4.12. C2,H1,02N requires c1= 82.2 ; H = 4.3 ; N = 4.00 per cent. When warmed with sulphuric acid, this phenylaminonaphthacene- quinone yields a strongly fluorescent solution, indicating that condens- ation has taken place with formation of the corresponding acridine derivative, but the latter substance has not yet been obtained in a state sufficiently pure for analysis. (l)-Hydroxybromcmaphthoylbelnzoic Acid and (1)-Hydroxybromo- naphthacenequinone. This acid was readily prepared by slowly adding bromine (40 grams) to (1)-hydroxynaphthoylbenzoic acid (60 grams) suspended in carbon disulphide. When the initial vigorous reaction had subsided, the whole was boiled on the water-bath for four hours and until no further evolution of hydrogen bromide was observed. The carbon disulphide was then distilled off and the residue, which consisted of the almost pure acid, was recrystallised from glacial acetic acid, a small quantity of sodium bisulphite being added to remove free bromine.The new bromo-acid separated in pale yellow crystals melting at 236'.NAPHTHOYLBENZOIC ACID Ah'D OF NAPHTHACENEQUINONE. 119 0.1822 gave 0.3875 CO, and 0.0465 H,O. 0.1'724 ,, 0.0862 AgBr. Br= 21.5. C, *H,BrO, requires C = 5 8.2 ; H = 3.0 ; Br = 2 1 5. (I) -HydroxybrornonnphthoyZbenzoic acid dissolves in sulphuric acid, yielding a brown solution which, on warming, becomes green, then blue, and finally deep red.I f this solution is heated to about 140°, at which temperature bromine begins to be evolved, and is then im- mediately poured into water, a red precipitate is deposited, which consists mainly of (1 )-hydroxybrornonaphthacenequinone. It is collected on a filter, washed with hot sodium carbonate solution, and crystal- lised from nitrobenzene, from which it separates in red needles, which do not melt at 300'. Owing to some elimination of bromine during the preparation, a specimen sufficiently pure to give good results on analysis was not obtained. C=57*9; H=2*8. (1 )-Chlorobromonaphthoylbenxoic Acid and (1 )-Chlorobromonaphthacme- quinone. Twenty grams of (1)-hydroxybromonaphthoylbenzoic acid (see last section) were mixed with a small quantity of benzene, and 23 grams of phosphorus pentachloride were added gradually, the whole being then warmed on the water-bath until no further evolution of hydrogen chloride occurred.The time required for the completion of the reaction was about four hours. Only a small quantity of the solvent and no excess of phosphorus pentachloride should be employed, other- wise a pale yellow, crystalline compound containing phosphorus is obtained, which, owing to its similar appearance and behaviour, is readily mistaken for the chlorobromonaphthoylbenzoic acid. This phosphorus compound gave considerable trouble, and various ex- pedients were tried to avoid its formation, such as varying the solvent used and heating phosphorus pentachloride with hydroxybromonaph- thoylbenzoic acid in the dry state. The former procedure always gave the phosphorus compound, and the latter variously halogenated mix- tures.It was found by using benzene as the solvent and taking special precautions that an excellent yield of the chlorobromo-acid could be obtained. At the end of the reaction, no solid matter should have separated, but the product should be a rather viscid, dark brown oil. Prom this as much benzene is distilled off as possible a t the temperature of the boiling water-bath. The residue is then treated with water and allowed to stand for some hours with frequent shaking, and until the acid chloride is completely decomposed. The white solid which separates is collected on a filter, washed, and recrystallised from glacial acetic acid, from which it separates in almost colourless crystals melting at 180'.120 OHCHARDSON AND WEIZMANN : SOME DERIVATIVES OF 0.2313 gave 0.4666 CO, and 0.0531 H,O.0.2296 ,, 0.1542 AgCl and AgBr. C1= 8.9 ; Br = 20.0. C,8H1,0,U1Br requires C = 55.4 ; H = 2.6 ; C1= 8.7 ; Br = 20.0 per cent. (l)-C'hZorobromonapT~thoylbenxoic acid undergoes similar colour changes to (1)-hydroxybromonaphthoylbenzoic acid when treated with concen- trated sulphuric acid, giving finally a chlorobromonaphthacenequinone, which, however, on account of the occurrence of partial decomposition during the reaction, was not obtained in a sufjiciently pure state for analysis. C = 55.0 ; H = 2.5. Methyl (1 )-Methozyna~hthoyZbenxoccte, ,Wethy I? ( 1 ) - Afethoxy-6-nitro- napTLthoylbenxoate, and (1 )-Hydroxy-6-nitronc~~T~tJ~oyZbenxoic Acid.I n order to prepare the first mentioned of these substances, ( 1)-hydroxynaphthoyl benzoic acid (40 grams) was dissolved in an excess of caustic potash (25 per cent.) containing about 40 grams of this alkali. To this solution, when quite cold, methyl sulphate (30 grams) was added in very small portions at a time with frequent shaking, cooling being resorted to when necessary. A still greater excess of Inethyl sulphate may often be used with advantage, but the solution must always remain alkaline. During the operation, a yellow substance separates out, either in the solid state or as an oil, according to the temperature at which the reaction is carried out. When cold, the solid is collected on a filter, washed, and recrystallised from glacial acetic acid.Methyl (1)-methoxynaphthoylbenzoate separates from acetic acid in colourless, transparent cryst.als, which become opaque on exposure to air and melt a t 110'. 0.2198 gave 0.6038 CO, and 0.1068 H,O. C20H,60, requires C = 75.0 ; H = 5.0 per cent. The yield of this substance varies and a considerable quantity of partially methylated acid remains in the alkaline solution. We have several times attempted to obtain (1)-methoxgnaphthacene- quinone by first partially saponifying the above-described methyl ester with caustic potash, and then acting on the free acid with concentrated sulphuric acid. Complete hydrolysis, however, occurs under these conditions and the product obtained is (1)-hydroxynaphthacene- quinone. ATitration.-The finely-po wdered methyl ( 1 )-rnethoxynaphthoyl- benzoate was treated with nitric acid (sp.gr. 1.42) in the cold, the vigorous reaction being kept under control by immersion in ice when necessary. A small portion of the ester passed into solution, the remainder changing first to a soft, and finally to a brittle mass, which C = 74.9 ; H = 5.3.NAPH'I'HOYLBENZOIC ACID AND OF NAPHTHACENEQUINONE. 121 floated on the surface of the liquid. After diluting with water, the solid matter mas collected, washed well, and recrystallised from glacial acetic acid, from which it separated in bright yellow crystals melting a t 136'. 0.1715 gave 0.4305 CO, and 0.0640 H20. 0.2272 ,, 8.6 C.C. N at IS0 and 762 mm. N=4*37. C = 68.4 ; H= 4.1. C2,Hl,0,N requires C = 68.3 ; H = 4.4 ; N = 3.82 per cent. From the methyl (1 )-~nethoxy-6-nitronaphthoylbenxoate, by boiling for five hours with strong caustic potash and then precipitating with hydro- chloric acid, (1 )-hydroxy-6-nitronaphthoyl6enxoic acid was obtained.It crystallises from glacial acetic acid in slender, lemon-yellow needles. 02126 gave 0.4920 CO, and 0.0460 H20. 0.2310 ,, 8.3 C.C. N at 17' and 762 mm. N = 4-18. C = 63.5 ; H = 3.3. C1,HllO,N requires C = 64.1 ; H = 3.0 ; N = 4.15 per cent. ( 1 )-Hydroxy-6-nitroizc6phthoylben~o~c acid melts at 220' and dissolves in caustic potash, forming a deep orange-red solution. When treated with concentrated sulphuric acid, it does not yield hydroxynitro- naphthacenequinone, because decomposition takes place with evolution of oxides of nitrogen. We next attempted to prepsre (l)-hydroxy-6-aminonaphthoylbenzoic acid by reducing the above-described hydroxynitro-acid, but found that the product of the reaction consisted of (l)-hydroxy-6-amino- naphthacenequinone. The experiment was conducted as follows : (l)-hydroxy-6-nitro- naphthoSlbenzoic acid was dissolved in hot glacial acetic acid, and then zinc dust gradually added in small quantities, when the solution became deep red and finally deposited minute, dark red, glistening crystals. After gently boiling for half an hour, the crystalline precipitate was collected on a filter while hot, washed with acetic acid and water, dried well, and extracted with nitrobenzene, from which solvent deep red crystals, insoluble in sodium carbonate, separated. 0.2131 gave 0.5896 CO, and 0.0847 H20, 0.2495 ,, 10.3 C.C. N at 1 5 O and 762 mm. N=4*9. C1,HI,O,N requires C = 743' ; H = 3.8 ; N = 4.7 per cent. (l)-Hydroxy-6-aminonaphthacenepzcicnone melts above 300O. It dissolves in caustic potash with a deep red colour, and its solution in concentrated sulphuric acid exhibits a beautiful and very strrong green fluorescence. C = 75.4 ; H = 4.40. THE VICTORIA UNIVERSITY OF MANCHESTER.