ADDITIONS OF ACIDS TO STILBENE AND STYRENE OXIDES 4091 studied. We repeated the procedure of the authors and obtained a product with the molecular formula C12H13Hg4N08. Infrared spectral analysis of this compound indicates the presence of an N-H peak a t 3450 cm.-' and an acetate peak a t 1610 cm.-l. The structure of the compound was thus identified as pyrrolyl-2,3,4,5-tetramercuric acetate.Solvolysis and Reduction.-When the solution of pyrrolyl-2,3,4,5-tetramercuric acetate in acetic acidtoluene (65 : 35) was treated with ferrocene under comparable conditions as that for phenylmercuric acetate,2 we observed the characteristic blue color of ferrocenium ion. Pyrrole was formed in 58% yield. Using acetic acid alone as solvent, no pyrrole was obtained from the reaction mixture, but some polymeric substances resulted with unsaturation bands in the 6-p region. Further characterization of this substance was not fruitful at this time.The appearance of blue ferrocenium ion and subsequent detection of pyrrole strongly suggests that there is similarity between this reaction and the reduction of phenylmercuric cation. The absence of pyrrolyl acetate also supports the assumption that the pyrrolylmercuric cation does not demercurate to yield the corresponding carbonium ion.' The formation of polymeric substances in acetic acid may reflect that the pyrrolyl radical is relatively stable, incapable of abstracting hydrogen from acetic acid. Thus, recombination of radicals leading to polymeric products becomes more important.The solvolysis and reduction are perhaps stepwise. Simultaneous reduction and demercuration should provide a benzyne type intermediate, for which we have not secured any evidence. Experiments with (7) F. Jensen and R. Ouellette, J . Am. Chem. Soc., 85, 4477, 4478 (1961).polymercuric acetates of thiophene and benzene are in progress in this laboratory.
Experimental SectionPreparation of Pyrroly1-2,3,4,5-tetramercuric Acetate.-Mercurie acetate (15 g., 0.042 mole, Merck Co.) was dissolved in 60 ml. of hot water and some red precipitate was iiltered immediately. Pyrrole (1.0 g., 0.015 mole, Eastman, freshly distilled, b.p. 13& 131') was added to the freshly filtered solution of mercuric acetate. The mixture was allowed to stand for 1 hr. A white precipitate, 2.9 g. (2073, was collected. It decomposed above 200' with the formation of mercury beads. The analytical sample was obtained by recrystallization from an acetic acidethanol mixture.
l.%/.Other mole ratios of pyrrole and mercuric acetate were tried in acetic acid aa well as water as solvent, but many difficulties were encountered. Using a mole-to-mole ratio of pyrrole and mercuric acetate, a dark blue viscous mess was obtained. When the amount of water was reduced, a gelatinous mixture resulted which made filtration impossible.
Solvolysis and Reduction of Fyrrolyl-2,3,4,5-tetramercuricAcetate.-To a solution containing 0.2 g. (2 X mole) of pyrrolyltetramercuric acetate in 1 ml. of glacial acetic acid with trace amounta of p-toluenesulfonic acid (Matheson Colema...
