Synthesis of optically active 2-benzyldihydrobenzopyrans for the hypoglycemic agent englitazone
作者:Frank J. Urban、Bernard S. Moore
DOI:10.1002/jhet.5570290223
日期:1992.3
nyl)-4H-1-benzopyran-4-carboxylic acid 16 was prepared from 11 by amidoalkylation with α-hydroxyhippuric acid in methanesulfonic acid solution followed by spiroalkylation to (4R,S)-2-benzyl-2,3-dihydro-6-(methoxycarbonyl)spiro[4H-benzopyran-4,4′-2′-phenyloxazolidin]-5′-one 15. After the phenyloxazolidin-5-one 15 was hydrolyzed to the spirobenzamido carboxylic acid 16, oxidative decarboxylation with
两个合成的某些光学活性的2-苄基-2,3-二氢-4- ħ -benzopyrans和苯并吡喃-4-酮被呈现。从D-和L-苯丙氨酸开始的不对称合成用于提供2-苄基-6-(甲氧基羰基)-2,3-二氢-4 H-苯并吡喃-4-酮19的两种对映体。苯丙氨酸在硫酸水溶液中重氮化。酸转化为2-羟基-3-苯基丙酸6,将其在四个步骤中转化为1-溴-2-(4-甲氧基羰基苯氧基)-3-苯基丙烷11。(4 R,S)-苯甲酰氨基-2-苄基-2, 3-二氢-6-(甲氧基羰基)-4 H -1-苯并吡喃-4-羧酸16由11制备通过在甲磺酸溶液中用α-羟基马尿酸进行酰胺烷基化,然后将其螺烷基化为(4 R,S)-2-苄基-2,3-二氢-6-(甲氧基羰基)螺[4 H-苯并吡喃-4,4'-2 ′-苯恶唑烷] -5′-one 15.将苯恶唑烷-5-酮15水解为螺并苯甲酰胺基羧酸16后,用次氯酸钠氧化脱羧得到旋光的2-苄基-6-(甲氧羰基)-2