Reactions of nickel 1,19-dimethyltetradehydrocorrin salts

Abstract

The action of alkali on the nickel 1,19-dimethyltetradehydrocorrin salts in air yields the neutral nickel 1,19-dimethyl-5-ketotridehydrocorrins, and a variety of other reactions yield the 15-substitution products of the 5-keto-compounds, e.g. the 15-formyl derivative from the action of chloroform and alkali on the original salts, the 15-cyano-derivative from the action of cyanide and the 15-nitro- and 10,15-dinitro-derivatives from nitrations. In all these cases intermediate products were recognised, and in the cyanide reaction, a stable radical was isolated which was converted into the nickel 5-cyano-1,19-dimethyltetradehydrocorrin bromide with hydrobromic acid. A stable nickel 5,15-dicyano-radical was also isolated which was converted into the nickel 5,15-dicyano-1,19-dimethyltetradehydrocorrin perchlorate with perchloric acid. The nickel 5-cyano- and 5,15-dicyano-1,19-dimethyltetradehydrocorrin iodides yielded the corresponding nickel 5-cyano- and 5,15-dicyano-porphins on thermolysis. The dibromo-derivative of the original nickel tetrahydrocorrin salt was isolated as the unstable perbromide, and this and the unstable chlorination product were converted into the 5,15-dimethyl derivative with lithium copper methyl. Thermolysis of the nickel 1,19-dimethyltetradehydrocorrin chlorides to the 2,3-oxido-derivatives of the corresponding nickel 20-methyl-2,3-chlorins along with the meso-unsubstituted nickel porphins is shown to be a general reaction.