SYNTHESIS, REACTIONS AND STEREOCHEMISTRY OF -HYDROXYMETHYL-2,3-DIHYDRO-4H-1,3-BENZOXAZIN-4-ONE AND SOME PERHYDROGENATED DERIVATIVES

-Hydroxymethyl-2,3-dihydro-4H-1,3-benzoxazin-4-one and a number of its perhydrogenated derivatives were prepared from the corresponding 2-hy droxycarboxamides by treatment with a formaldehyde/formic acid mixture . Thermal decomposition of the 3-hydroxymethyl derivatives led to the previously unknown parent compounds. With one exception (14), both in the N-unsubstituted (16-18) and in the N-substituted (7-15) cyclopenta ne- and cyclohexane-fused derivatives the oxazinone ring predominantly attains a single half-chair conformation.