Hydrochloric Acid → 5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophen-4-amine hydrochloride

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Reaction Steps

5,6,7,8-Tetrahydro=4H-cyclohepta[b]thiophen-4-one is converted to N-(5,6,7,8-tetrahydro-4H-cyclohepta[b]thien-4-yl)formamide, m.p. 164°-166° C., by the method of Xloetzel et al., Journal of Organic Chemistry 18, 1511 (1953). Hydrolysis of the formanide is accomplished by refluxing for one hour in 1 N hydrochloric acid and evaporating to dryness to afford 5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophen-4-amine hydrochloride, m.p. 233°-236° C. dec. The amine hydrochloride is then allowed to react with methyl isocyanate in dry tetrahydrofuran as solvent in the presence of a stoichiometric equivalent of triethylamine to afford 1-methyl-3-(5,6,7,8-tetrahydro-4H-cyclohepta[b]thien-4-yl)urea, m.p. 220°-222° C.

Provenance & Evidence