Preparation of oxazoline N-oxides and imidate N-oxides by amide acetal condensation and their [3+ 2] cycloaddition reactions

SP Ashburn, RM Coates

Index: Ashburn, Stephen P.; Coates, Robert M. Journal of Organic Chemistry, 1985 , vol. 50, # 17 p. 3076 - 3081

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Citation Number: 29

Abstract

Since earlier attempts to isolate 3a led to formation of impurities, 2 the presence of the oxazoline N-oxide was demonstrated by trapping the nitrone as a cycloadduct (7a) in 82% yield upon addition of phenyl isocyanate. Similar condensation of benzamide acetal 2b3" with 1 afforded a 21 mixture of 4, 4-dimethyl-2-phenyloxazoline N-oxide (3b) and N, N- dimethylbenzamide that could be separated by distillation. The crystalline phenyl- ...