Roets E, Vlietinck A, Vanderhaeghe H
J Antibiot (Tokyo). 1977 Oct;30(10):847-55. doi: 10.7164/antibiotics.30.847.
The preparation of 6-epi-ampicillin by hydrolysis of 6-epihetacillin is described. During this conversion, the formation of a diketopiperazine was also observed. The best yield was obtained at pH 7.0 and room temperature for 3 approximately 7 hours. The lowest yield of 6-epi-ampicillin and the highest formation of the diketopiperazine occurred in pyridine - acetic acid - water. Treatment of ampicillin (with D-aminophenylacetyl side chain) with nitrous acid gave alpha-hydroxybenzylpenicillin with about 66% of L- and 34% mandelyl side chain. Reaction 6-epi-ampicillin gave 6-epi-alpha-hydroxybenzylpenicillin with practically the same ratio of L- and D-isomers.
描述了通过6-表异氨苄青霉素水解制备6-表氨苄青霉素的方法。在该转化过程中，还观察到了二酮哌嗪的形成。在pH 7.0和室温下反应约3至7小时可获得最佳产率。在吡啶-乙酸-水体系中，6-表氨苄青霉素的产率最低，二酮哌嗪的生成量最高。用亚硝酸处理氨苄青霉素（带有D-氨基苯乙酰侧链）得到α-羟基苄青霉素，其L-型和扁桃基侧链比例约为66%和34%。6-表氨苄青霉素反应得到6-表-α-羟基苄青霉素，其L-型和D-型异构体比例几乎相同。
