Optimization of conditions for the reaction between β-lactam carbenes and 3,6-di-(2-thienyl)tetrazine

2016 ARKIVOC  
The reaction between β-lactam carbenes and 3,6-di-(2-thienyl)tetrazine was studied, affording novel 5,8-di(thien-2-yl)-1,6,7-triazaspiro[3.4]octa-5,7-dien-2-ones and 7-(thien-2-yl)-3,3adihydrothieno[2′,3′:3,4]cyclopenta[1,2-b]pyrrol-2(1H)-ones on heating at approximately 100 °C. The reaction proceeded by cascade mechanisms, and made this series "reactions rich". This study extends the application of β-lactam carbenes to the synthesis of complex heterocycles. intermediates 5
more » ... 5,8-di(thien-2-yl)-1,6,7-triazaspiro[3.4]octa-5,7-dien-2-ones) and the final products 9 (3,3a-dihydrothieno[2′,3′:3,4]cyclopenta[1,2-b]pyrrol-2(1H)-ones) in moderate yields over different heating times, and evidence was obtained that the electron-rich substituent on the tetrazine slowed down the addition. This study has extended this reaction series and provided a strategy for synthesizing novel heterocyclic pyrrol-2-one compounds. Scheme 1. Proposed mechanisms for the reactions of β-lactam carbenes with 3,6-di-(2-thienyl)tetrazine.
doi:10.3998/ark.5550190.p009.524 fatcat:efdmmeiwe5gs5fd5apbp3s35ui