NaBH4 reduction of citraconimide derivatives regioselectively afforded 5-hydroxy-4-methyl-1,5-dihydropyrrol-2-ones, whereas NaBH4–CeCl3 or DIBAL-H reduction gave 5-hydroxy-3-methyl-1,5-dihydropyrrol-2-ones.
A new method for the synthesis of 5-hydroxy-3-pyrrolin-2-ones is reported. Conversion of N-Boc-3-pyrrolin-2-ones into 2-triisopropylsilyloxypyrroles and ensuing oxidation with dimethyldioxirane provides the corresponding N-Boc-5-hydroxy-3-pyrrolin-2-ones in high yields.
Convenient route to both enantiomers of chiral 5-hydroxypyrrolidin-2-one and 5-hydroxy-1,5-dihydropyrrol-2-one: reverse enantioselectivity in lipase-catalyzed kinetic resolution
作者:Kunihiko Takabe、Masahisa Suzuki、Toshiki Nishi、Masaomi Hiyoshi、Yasuaki Takamori、Hidemi Yoda、Nobuyuki Mase
DOI:10.1016/s0040-4039(00)01745-7
日期:2000.12
High enantioselectivity was achieved in the lipase-catalyzedkineticresolution of 5-hydroxypyrrolidin-2-one and 5-hydroxy-1,5-dihydropyrrol-2-one derivatives. Lipase PS and Novozym 435 were the successful catalysts (E=>1000). The acetylation of the N-protected 5-hydroxy-1,5-dihydropyrrol-2-one derivative gave the (R)-acetate with high enantioselectivity, while, without N-protection, the (S)-acetate
FRESHLY redistilled pyrrole dissolved in water, alcohol or acetone and mixed with 0.5 Ã 10-1 M methylene blue rapidly takes up oxygen in the light but not in the dark. Pyrrole alone is not oxidized. The rate of oxygen uptake is a linear function of light intensity. Eosin, but not fluorescein, can be used instead of methyleno blue. Tests with standard optical filters showed the effective wave-lengths to be within, the range of 5200â5800 A. On the basis of 5500 A., the energy necessary to institute the reactionis 3.4 Ã 10-12 ergs/molecule.
新鲜重蒸馏的吡咯溶解在水、酒精或丙酮中,并与 0.5 × 10-1 M 亚甲蓝混合,在光下迅速吸收氧气,但在黑暗中则不会。单独的吡咯不被氧化。摄氧率是光强度的线性函数。可以使用曙红代替亚甲基蓝,但不能使用荧光素。使用标准滤光片进行的测试表明,有效波长在 5200-5800 A 范围内。以 5500 A 为基础,发生反应所需的能量为 3.4 × 10-12 尔格/分子。