2,6-Dimethoxybenzoyl chloride → 2-Isocyanato-1,3-dimethoxybenzene

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Reaction Steps

A solution of 1-methyl-2-iminopyrrolidine in benzene is prepared from 10.73 g. (0.08 mole) of the hydrochloride salt in the usual manner. 2,6-Dimethoxyphenylisocyanate is prepared in 81% yield (crude) from 2,6-dimethoxybenzoyl chloride by the method of K. Inukai and Y. Maki, Kogyo Kagaku Zasshi, 67, (5) 807-9 (1964). A benzene solution of 13.45 g. (0.075 mole) of the 2,6-dimethoxyphenylisocyanate is added to the benzene solution of 1-methyl-2-iminopyrrolidine and the reaction mixture is stirred for 1.5 hours at room temperature. A white precipitate, which forms, is filtered off and discarded. The filtrate is reduced to dryness under reduced pressure to give a clear, viscous oil that crystallizes on cooling. Recrystallizations from ethyl acetate-ether and ethyl acetate gives 1-(1-methyl-2-pyrrolidylidene)-3-(2,6-dimethoxyphenyl)urea as white crystals, m.p. = 114°-117° C.

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