Reaction of penicillin sulfoxides with diethyl phosphorocyanidate (DEPC) was investigated. Treatment of benzylpenicillin (S)-sulfoxide methyl ester (4a) with a slight excess of DEPC in N, N-dimethylacetamide gave the 3-cephem (5a), the 2-cephem (6a). and the 3-methylenecepham (7a) in 22, 4, and 4% yields, respectively. Increase of the quantity of DEPC to a three or five fold excess increased the yield of the 3-cephem (5a). Phenoxymethylpenicillin (S)-sulfoxide methyl ester (4b) also afforded the 3-cephem (5b) and the 3-methylenecepham (7b) under analogous reaction conditions as above, while phthalimidopenicillin (R)-sulfoxide methyl ester (8) furnished the 3-cephem (9) and the isothiazolones (10 and 11).
研究了
青霉素硫醚与膦
氰酸二
乙酯(
DEPC)的反应。在 N,N-二甲基乙酰胺中用微量过量的
DEPC 处理苄
青霉素 (S)-亚砜甲酯 (4a),得到 3-头孢 (5a)、2-头孢 (6a) 和 3-亚甲基头孢 (7a),产率分别为 22%、4% 和 4%。将
DEPC 的用量增加到过量的三倍或五倍,可提高 3-cephem(5a)的产率。在上述类似的反应条件下,吩氧甲
青霉素(S)-亚砜甲酯(4b)也能生成 3-
头孢菌素(5b)和 3-亚甲基
头孢菌素(7b),而
酞酰亚胺青霉素(R)-亚砜甲酯(8)能生成 3-
头孢菌素(9)和
异噻唑酮(10 和 11)。