Proton- and iodine-induced cyclization of 2-(pent-4-en-1-yl)quinazolin-4(3H)-ones: synthesis of pyrrolo[2,1-b]quinazolinone and pyrido[1,2-a]quinazolinone derivatives

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发表日期：

2024年9月1日

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Ruslan I. Vaskevych,
Alla I. Vaskevych,
Nataliia O. Savinchuk,
Maryna V. Stasevych,
Svitlana V. Shiskina,
Mykhailo V. Vovk

摘要

2-(Pent-4-en-1-yl)quinazolin-4(3H)-ones in CF₃SO₃H solution undergo preferential cyclization into 1-ethyl-2,3-dihydropyrrolo[2,1-b]quinazolin-9(1H)-ones via the intermediate rearrangement in the alkenyl moiety, while 9-methyl-6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-ones are minor products. Iodocyclization of 2-(pent-4-en-1-yl)quinazolin-4(3H)-ones proceeds according to the 6-exo-trig cyclization mode to form 1-(iodomethyl)-1,2,3,4-tetrahydro-6H-pyrido[1,2-a]quinazolin-6-ones, which are further converted to their hexahydro derivatives by the diastereoselective reduction with NaBH₄.