| 摘要 |
<p>PURPOSE:To readily obtain the compound useful as an intermediate for medicines in a high purity and yield by reducing nitro group in a raw material compound such as ethyl chloro-methoxycarbonyl-nitrophenoxyacetate according to a specific method. CONSTITUTION:This method for producing a 1,4-benzoxazine compound is to react a compound expressed by formula I (R<1> and R<2> are each H or an alkyl; R<3> is an alkoxy; R<4> and R<5> are each H, a halogen, etc.; R is H or a carboxylic acid-protecting group) with sodium dithionite in an aprotic polar solvent (preferably DMF) and provide the compound expressed by formula II. A solution of the compound expressed by formula I in a mixture of the solvent with water in small portions is preferably dropped into a solution of the sodium dithionite in the solvent and the reaction is then carried out at 100-120 deg.C for 1-2hr. Furthermore, ethyl 4-chloro-2-methoxycarbonyl-6-nitrophenoxyacetate is preferred as the compound expressed by formula I to provide methyl 6-chloro-3-oxo-3,4- dihydro-2H-1,4-benzoxazine-8-carboxylate as the compound expressed by formula II therefrom.</p> |
