Study on selectivity in the reaction of 2-substituted pyridinium-N-imines with dimethyl acetylenedicarboxylate

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• 作者：Vyacheslav I. Supranovich^a ; ^b ; Aleksey Yu. Vorob&rsquo ; ev^a ; ^b ; Gennady I. Borodkin^a ; ^b ; ^{gibor@nioch.nsc.ru" class="auth_mail" title="E-mail the corresponding author} ; Yury V. Gatilov^a ; ^b ; Vyacheslav G. Shubin^a
• 关键词：1 ; 3-Dipolar cycloaddition ; N-Amine salts ; Pyrazolo[1 ; 5-a]pyridines ; Selectivity ; C&ndash ; X bond cleavage ; DFT calculations
• 刊名：Tetrahedron Letters
• 出版年：2016
• 出版时间：9 March 2016
• 年：2016
• 卷：57
• 期：10
• 页码：1093-1096
• 全文大小：981 K

文摘

Reactions of 2-X-pyridinium-N-imines (X = F, Cl, Br, CN, OPh, NH₂, N-morpholine) with dimethyl acetylenedicarboxylate (DMAD) have been studied. In the case of X = Cl, Br, CN, OPh both 7-substituted- and 7-H-pyrazolo[1,5-a]pyridines are formed. The 7-H/7-X ratio usually increases with the growing solvent polarity. The reaction of N-amino-2-iminopyridine with DMAD gives substituted pyrido[1,2-b][1,2,4]triazine.