Abstract
Ethyl cyanoacetate (1a) or its methyl derivatives (1b and 1c) were treated with HCl/EtOH to give the corresponding imidates (2a-2c). Treatment of the latter compounds with cysteamine gave ethyl 2-thiazoline-2-acetate (3a-3c), which by reduction with sodium cyanoborohydride in HCl/MeOH gave the corresponding thiazolidines (4a-4c). Hydrolysis followed by β-lactam formation through the use of Mukaiyama-Ohno's reagent afforded 7-oxo-4-thia-1-azabicyclo [3. 2. 0] heptane (6a) and its methylated derivatives (6b and 6c).
