| 摘要 |
Title compds. [I; R = C1-20 alkyl, aryl-lower alkyl, cycloalkyl-lower alkyl; R1 = H, -CO-R4(R4 = lower alkyl, phenyl, phenyl-lower alkyl); R2 = lower alkyl; R3 = H, C1-2 lower alkyl having alleviative activity of pain and nervous sedative activity, were prepd. as follows. Phenyl-type benzopyrans(II) were esterified to give esters(III), which were oxidized at 80-100≦̸C for 1-2hrs. to give oxo-ester benzopyrans(IV). These were hydrolyzed in basic aq. soln. to give I.
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