Vol. 65
476
NOTES Symmetrical Biaryls from Diazotized Amines. Reducing Agents. I1
copper ( 5 4 g.); the amount of metal consumed is of no significance for a separate experiment showed it to be attacked by the ammoniacal solution in the absence of the BY EDWARD R. ATKINSON, D. HOLM-HANSEN, diazo solution. The filtrate was carefully acidified with A. D. NEVERSAND S. A. MARINO hydrochloric acid a t about 60' to precipitate the crude We have continued our systematic examination' product, which was then leached with 50 cc. of boiling water. It was then recrystallized from glacial acetic acid, of those reducing agents which might convert the less soluble portion consisting of diphenylamine-2,2'diazotized amines to symmetrical biaryls. As dicarboxylic acid (10yo yield), the more soluble portion in the previous work diazotized anthranilic acid being diphenic acid (67-71% yield). Formic Acid.-This reagent, in conjunction with small has been used and the work has been confined to aqueous solutions. None of the agents here amounts of copper powder, has brought about biaryl formadescribed are as effective as those previously tion' but the procedures have been confined to essentially anhydrous conditions. Tobias' observed deamination in studied but our results are of interest because the the naphthylamine sulfonic acid series under aqueous conuse of "standard" conditions and a single diazo- ditions. tized amine makes possible a comparison of the We observed that when solutions of benzenediazonium formate were mixed with 23 N formic acid in a variety of relative effectiveness of these agents. proportions no reaction occurred unless the mixture was warmed; salicylic acid was formed in a t least 70y0yield Experimental and no other product was detected. When copper powder Copper Powder in Aqueous Suspension.-It has been was added to the cold mixture nitrogen was slowly evolved reported that the use of this agent leads to the formation and after working up the products in the usual way there of the RH product,* the RX product,' and the biaryl,' impure diphenic acid were isolated benzoic acid (40y0), the latter being obtained in 60% yield when diazotized u(lo%), and a small amount of tar. The crude product also nitroaniline was used, gave a positive ferric chloride test. Our general experimental procedure has already been deEthyl Alcohol.-The use of this material (either with or 5cribed.I Ten grams of anthranilic acid was diazotized in without the use of copper) in deamination is well known the usual way and in a typical run the diazo solution was but Gattermann and ErhardtO obtained by its use a 22% added during thirty minutes to a suspension of 10 g. of yield of biphenyl from diazotized aniline and a number of activated6 copper powder suspended in 70 cc. of water, other investigators have obtained small amounts of the bitemperature was &loo. At the conclusion of the addition aryl when studying its action on a variety of diazotized the mixture gave a negative diazo test with @-naphthol. amines. An excess of solid sodium bicarbonate was added to disTen grams of anthranilic acid was diazotized in the usual solve the acidic products and a mixture of copper powder way using hydrochloric acid. The resulting solution (6 9.) and hydrated cuprous oxide was filtered from the (volume = 100 cc.) was then mixed with an equal volume solution. The filtrate was acidified to precipitate a cream of 9570 ethyl alcohol and warmed. In some experiments colored solid which was separated into diphenic acid, m. p the diazo solution was allowed to flow into boiling alco215-220" (32% yield), and o-chlorobenzoic acid, m. p hol. In all experiments the only organic product isolated 133-140' (54% yield), by the use of boiling ligroin (b. p was salicylic acid (jo-75y0 yield). Acetaldehyde was 90-120') in which the diphenic acid is only slightly soluble. formed in small amounts. The procedure used in isolating Copper Powder in Dilute Ammonium Hydroxide Sohthe acid was such that any ethyl salicylate originally tion.-Vorlander and M e y d had obtained a 20% yield formed would be hydrolyzed. of diphenic acid along with an unidentified substance of When the diazo solution was mixed with an equal volunir high melting point by use of this reagent. In our work thc of ethyl alcohol and the mixture stirred at 0" with 2 g. of procedure used uab the same as that described in the precopper powder, large amounts of acetaldehyde were ceding paragraph, the copper ponder however was sub formed and the diazo compound was entirely destroyed at pended in a mixture of 30 cc. of water and 30 cc. of concenthe end of thirty minutes; the copper was completely distrated ammonium hydroxide. I t was found by experiment solved. From the crude product there was obtained by that the metal could be used as received without the cu+ tomary washing to remove oil At the conclusion of the sublimation benzoic acid (50% yield) contaminated with a small amount of o-chlorobenzoic acid. From the residue reaction the ammoniacal solution was filtered free of excess there was isolated 0.2 g. of impure azobenzene-a,a'-di(1) Atkinson, et al., Tars JOURNAL, 63,730 (1941). carboxylic acid, m. p. 231-238' dec., which was further (2) Ayliag, Gorvin and Hinkel, J . Chcm. S o t . . 613 (1941). (3) Ullmaan, Bcv., 99, 1879 (1896). (4) Niementowski, i b i d . , 34, 3327 (1901). '5) Kleiderer and Adams, THISJOUR"., 66, 4226 (1933) 'ti') Vorl:inclPr a n d M w e r s d x i i , 320, 142 (19021
(7) (a) Gerngross and Dunkel, Bcr., 67, 739 (1924); (b) Brv downa, Chcm. Abstr., 92, 2372 (1928). (8) Tobias,Bcr., 23,1631 (1890). i9) Cattermznn arid I
