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Aryl Nitrile Imines and Diazo Compounds. Formation of Indazole, Pyridine N-Imine, and 2-Pyridyldiazomethane from Tetrazoles.
The Journal of Organic Chemistry ( IF 3.3 ) Pub Date : 2020-05-20 , DOI: 10.1021/acs.joc.0c00773 Didier Bégué 1 , Alain Dargelos 1 , Curt Wentrup 2
The Journal of Organic Chemistry ( IF 3.3 ) Pub Date : 2020-05-20 , DOI: 10.1021/acs.joc.0c00773 Didier Bégué 1 , Alain Dargelos 1 , Curt Wentrup 2
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Both photolysis and flash vacuum pyrolysis (FVP) of tetrazoles (1/5) are known to generate nitrile imines (13, 19, and 38), which rearrange to 1H-diazirines, imidoylnitrenes, and carbodiimides. Moreover, FVP of 5-aryltetrazoles is a convenient source of aryldiazo compounds (30/47) and arylcarbenes, including pyridylcarbenes. The factors that determine which path is followed are poorly understood. Calculations at the density functional theory and CASPT2 levels now examine cyclization of N-phenylnitrile imine 13 to indazole 17. A corresponding cyclization of C-phenylnitrile imine 19 can also lead to indazole, but this reaction, which passes through a carbenic nitrile imine, requires a much higher activation energy and is therefore not competitive with the known rearrangements to phenyldiazirines, ring expansion to diazenylcycloheptatetraene, or a new, potential rearrangement to cyanoazepine. C-(2-Pyridyl)nitrile imine 38 is predicted to undergo a new rearrangement to cyanopyridine N-imide 40 with an activation energy of 43 kcal/mol. The experimental observation that 2-pyridyldiazomethane 47 is actually formed requires a reaction with an energy barrier below 43 kcal/mol. This is found in the H-transfer from the tetrazole ring in 5-(2-pyridyl)tetrazole to the pyridine ring with a subsequent formation of 1H-2-(diazomethylene)pyridine and elimination of N2 with a barrier of ca. 26 kcal/mol. This new, facile mechanism has not previously been considered.
中文翻译：
芳腈亚胺和重氮化合物。由四唑形成吲唑，吡啶N-亚胺和2-吡啶基重氮甲烷。
四唑（两个光解和闪热解真空（FVP）1 / 5）是已知的，以产生腈亚胺（13，19，和38），其重排成1个ħ -diazirines，imidoylnitrenes，和碳二亚胺。此外，5-aryltetrazoles FVP是aryldiazo化合物（的方便来源30 / 47）和arylcarbenes，包括pyridylcarbenes。决定遵循哪条路径的因素知之甚少。在密度泛函理论和CASPT2水平上的计算现在检查了N-苯基腈亚胺13向吲唑17的环化。C-苯基腈亚胺19的相应环化反应也可导致吲唑，但该反应通过羧腈亚胺，需要更高的活化能，因此与已知的重氮苯重氮竞争，环扩环为二氮烯基环庚二烯不竞争，或可能重新配置成氰基氮杂。C-（2-吡啶基）腈亚胺38预计将以43kcal / mol的活化能经历新的重排为氰基吡啶N-酰亚胺40。2-吡啶基重氮甲烷47的实验观察实际上形成的H 2 O需要具有低于43kcal / mol的能垒的反应。在5-（2-吡啶基）四唑中的四唑环到吡啶环的H-转移中，随后形成1 H -2-（重氮亚甲基）吡啶，并以约2的势垒消除N 2，发现了这一点。26 kcal / mol。以前从未考虑过这种新的简便机制。
更新日期：2020-06-19
中文翻译：
芳腈亚胺和重氮化合物。由四唑形成吲唑，吡啶N-亚胺和2-吡啶基重氮甲烷。
四唑（两个光解和闪热解真空（FVP）1 / 5）是已知的，以产生腈亚胺（13，19，和38），其重排成1个ħ -diazirines，imidoylnitrenes，和碳二亚胺。此外，5-aryltetrazoles FVP是aryldiazo化合物（的方便来源30 / 47）和arylcarbenes，包括pyridylcarbenes。决定遵循哪条路径的因素知之甚少。在密度泛函理论和CASPT2水平上的计算现在检查了N-苯基腈亚胺13向吲唑17的环化。C-苯基腈亚胺19的相应环化反应也可导致吲唑，但该反应通过羧腈亚胺，需要更高的活化能，因此与已知的重氮苯重氮竞争，环扩环为二氮烯基环庚二烯不竞争，或可能重新配置成氰基氮杂。C-（2-吡啶基）腈亚胺38预计将以43kcal / mol的活化能经历新的重排为氰基吡啶N-酰亚胺40。2-吡啶基重氮甲烷47的实验观察实际上形成的H 2 O需要具有低于43kcal / mol的能垒的反应。在5-（2-吡啶基）四唑中的四唑环到吡啶环的H-转移中，随后形成1 H -2-（重氮亚甲基）吡啶，并以约2的势垒消除N 2，发现了这一点。26 kcal / mol。以前从未考虑过这种新的简便机制。
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