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).
氰基
乙酸乙酯(1a)或其甲基衍
生物(1b 和 1c)经 HCl/EtOH 处理后得到相应的
亚胺酸盐(2a-2c)。用半
胱胺处理后一种化合物,可得到 2-
噻唑啉-2-
乙酸乙酯(3a-3c),用
氰基硼氢化钠在 HCl/MeOH 中还原,可得到相应的
噻唑烷(4a-4c)。使用 Mukaiyama-Ohno 试剂
水解后形成 β-内酰胺,得到 7-oxo-4-thia-1-azabicyclo [3.