Regioslective Hydride Reduction of 2-(N-cyanoimino)thiazolidine Derivatives
摘要:
Treatment of 3-alkyl-2-(N-cyanoimino)thiazolidines with lithium aluminum hydride caused reductive cleavage of the imino double bond to afford 3-alkylthiazolidines, while diisobutylaluminum hydride reduction of 3-alkyl- and 3-sulfonyl derivatives resulted in the nitrile reduction or imino-nitrile bond cleavage to give 2-formyliminothiazolidines and/or 2-iminothiazolidines.
3-Methyl 1,3-thiazolidines 3a-c can be prepared easily in good yields by the reaction of β-mercaptoamine derivatives 1a-c with formalin and formic acid in a one-pot operation. The same procedure is also suitable for the construction of the 3-methyl-tetrahydro-1,3-thiazine skeleton from γ-mercaptoamines as exemplified in the synthesis of 3d.