| 摘要 |
<p>The present invention provides a novel 7a-alkoxy-4H-pyrano-Ä3,2-dÜ-oxazol-2(3H)-one represented by the formula (I): <CHEM> wherein R<1> and R<2> each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an aralkyl group; R<3> represents an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, provided that a 2-alkenyl group is excluded from the alkenyl group of R<3>; and R<4> represents an alkyl group, an aryl group, an alkoxycarbonyl group or a cyano group, and a process for producing the same which comprises reacting 5-alkoxy-2(3H)-oxazolone with an alpha , beta -unsaturated ketone in the presence of a Lewis acid in a solvent.</p> |
