Reisinger Ales, Bernhardt Paul V, Wentrup Curt
Department of Chemistry, School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Qld 4072, Australia.
Org Biomol Chem. 2004 Jan 21;2(2):246-56. doi: 10.1039/b311247k. Epub 2003 Dec 10.
Several tetrazolo[1,5-a]pyridines/2-azidopyridines undergo photochemical nitrogen elimination and ring expansion to 1,3-diazacyclohepta-1,2,4,6-tetraenes, as well as ring cleavage to cyanovinylketenimines, in low temperature Ar matrices. 6,8-Dichlorotetrazolo[1,5-a]pyridine/2-azido-3,5-dichloropridine undergoes ready exchange of the chlorine in position 8 (3) with ROH/RONa. 8-Chloro-6-trifluoromethyltetrazolo[1,5-a]pyridine undergoes solvolysis of the CF(3) group to afford 8-chloro-6-methoxycarbonyltetrazolo[1,5-a]pyridine. Several tetrazolopyridines/2-azidopyridines afford 1H- or 5H-1,3-diazepines in good yields on photolysis in the presence of alcohols or amines. 5-Chlorotetrazolo[1,5-a]pyridines/2-azido-6-chloropyridines and undergo a rearrangement to 1H- and 3H-3-cyanopyrroles and, respectively. The mechanism of this rearrangement was investigated by (15)N-labelling and takes place via transient 1,3-diazepines. The structures of 6,8-dichloro-tetrazolo[1,5-a]pyridine, 6-chloro-8-ethoxytetrazolo[1,5-a]pyridine, dipyrrolylmethane, and 2-isopropoxy-4-dimethylamino-5H-1,3-diazepine were determined by X-ray crystallography. In the latter case, this represents the first reported X-ray crystal structure of a 5H-1,3-diazepine.
几种四唑并[1,5 - a]吡啶/2 - 叠氮吡啶在低温氩气基质中会发生光化学脱氮和环扩展生成1,3 - 二氮杂环庚 - 1,2,4,6 - 四烯，以及环裂解生成氰基乙烯基酮亚胺。6,8 - 二氯四唑并[1,5 - a]吡啶/2 - 叠氮 - 3,5 - 二氯吡啶中的8位（3）氯可与ROH/RONa迅速发生交换。8 - 氯 - 6 - 三氟甲基四唑并[1,5 - a]吡啶的CF(3)基团会发生溶剂解反应生成8 - 氯 - 6 - 甲氧基羰基四唑并[1,5 - a]吡啶。几种四唑吡啶/2 - 叠氮吡啶在醇或胺存在下光解时能以良好产率生成1H - 或5H - 1,3 - 二氮杂卓。5 - 氯四唑并[1,5 - a]吡啶/2 - 叠氮 - 6 - 氯吡啶分别会重排为1H - 和3H - 3 - 氰基吡咯。通过(15)N标记研究了这种重排的机理，其通过瞬态1,3 - 二氮杂卓发生。通过X射线晶体学确定了6,8 - 二氯 - 四唑并[1,5 - a]吡啶、6 - 氯 - 8 - 乙氧基四唑并[1,5 - a]吡啶、二吡咯甲烷和2 - 异丙氧基 - 4 - 二甲基氨基 - 5H - 1,3 - 二氮杂卓的结构。在后一种情况下，这代表了首次报道的5H - 1,3 - 二氮杂卓的X射线晶体结构。
