The preparation of carbocyclic 4-deazaformycin and its 5′-homoanalogue from a common vinyl precursor, and its N-1 and N-2 methyl derivatives is reported. The syntheses began with a highly stereoselective SN2 reaction between lithio 4-picolines and a protected 2,3-dihydroxy-4-vinylcyclopentyl triflate. The requisite fused pyrazole ring was created by an intramolecular diazonium reaction that was followed by vinyl transformation into the hydroxymethyl and the hydroxyethyl groups. The N-methyl derivatives arose by standard methylation conditions and the resultant N-Me regiochemistry was assigned by homo- and heteronuclear NMR spectroscopy.
本研究报告介绍了从一种常见的
乙烯基前体制备碳环 4-脱氮福霉素及其 5′-同族异构体,以及其 N-1 和 N-2 甲基衍
生物的过程。合成过程始于 4-
吡啶锂和受保护的 2,3-二羟基-4-
乙烯基环戊基三酸酯之间的高度立体选择性 SN2 反应。分子内重氮反应生成了所需的融合
吡唑环,随后
乙烯基转化为羟甲基和羟乙基。在标准甲基化条件下产生了 N-甲基衍
生物,并通过同核和异核核磁共振谱确定了由此产生的 N-Me 区域
化学。