The facile syntheses of previously unreported 2,3- and 3,4-unsaturated derivatives of N-glycolylneuraminic acid are herein described. The procedure involves a ring-opening of the 4,5-oxazoline of N-acetylneuraminic acid, the acylation of the intermediate free amine, its conversion into the 4,5-oxazoline of N-glycolylneuraminic acid and the subsequent Ferrier reaction or C4 nucleophilic substitution.

中文翻译：

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直接获得N-羟甲基神经氨酸的2,3-和3,4-不饱和衍生物

本文描述了以前未报道的N-羟乙酰神经氨酸的2,3-和3,4-不饱和衍生物的简便合成。该方法涉及N-乙酰神经氨酸的4,5-恶唑啉的开环，中间体游离胺的酰化，其转化为N-羟乙酸神经氨酸的4,5-恶唑啉和随后的Ferrier反应或C4亲核替代。