作者:H. Esterbauer、A. Ertl、N. Scholz
DOI:10.1016/0040-4020(76)87015-9
日期:1976.1
and 2b. Whereas 2a and 2b were the only products even in reactions carried out with a molar ratio of aldehyde : cysteine ≧ 1, ratio < 1 was required to obtain a thiazolidine derivative in reactions with hydroxypentenal. The structures of compound 2a, 2b, 3 and 4 were ascertained by means of UV, IR and NMR measurements, potentiometric titrations, determination of the rate laws and elemental analysis.
半胱氨酸在两步反应中加入了丙烯醛,巴豆醛和4-羟基戊烯醛。第一加成产物是β-半胱氨酰基取代的饱和醛1a,1b和3。只能分离通过分子内半缩醛形成稳定的3的单加合物。衍生物1a和1b与另外的半胱氨酸迅速反应,得到噻唑烷化合物2a和2b。而2a和2b即使在醛:半胱氨酸摩尔比≥1的反应中也是唯一的产物,在与羟基戊烯的反应中获得噻唑烷衍生物也需要比率<1。通过UV,IR和NMR测量,电位滴定,速率定律的确定和元素分析来确定化合物2a,2b,3和4的结构。所有加合物均与半胱氨酸和母体醛保持平衡。估计正向和反向反应的速率常数。正向反应的速率增加约。在2-10的pH范围内,每个pH单位的10倍。