Regioselectivities in deprotonation of 2-(4-chloro-2-pyridyl)benzoic acid and corresponding ester and amide
作者:Anne-Sophie Rebstock、Florence Mongin、François Trécourt、Guy Quéguiner
DOI:10.1016/j.tet.2004.01.050
日期:2004.3
regiospecifically, as demonstrated by subsequent quenching with electrophiles. The lithio derivative at C3′ is only evidenced from the benzamide at higher temperature (−50 °C), when treated with LTMP in THF; it instantly cyclizes to 1-chloro-4-azafluorenone. The latter is converted to onychine, an alkaloid endowed with anticandidal activity.
处理2-(4-氯-2-吡啶基)苯甲酸乙酯,2-(4-氯-2-吡啶基)苯甲酸乙酯和N,N-二异丙基-2-(4-氯-2-吡啶基)苯甲酰胺用LTMP在-75°C下的THF溶液中,C5'处的硫代衍生物是区域特异性生成的,随后通过亲电试剂淬灭证明了这一点。当在LTMP中在THF中处理时,只有在较高的温度(-50°C)下,苯甲酰胺才能证明C3'处的硫代衍生物。它立即环化为1-氯-4-氮杂芴酮。后者被转化为Onychine,一种具有抗候选活性的生物碱。