Yb(OTf)3-Catalyzed Synthesis of 2-Substituted 4(3H)-Quinazolinones via Cleavage of a Carbon-Carbon Bond
摘要:
A general, selective, and practical one-pot synthesis of 2-substituted 4(311)-quinazolinones by the Yb(OTf)(3)-catalyzed cyc/o-condensation of 2-aminobenzamides with acyclic or cyclic 1,3-diketones (beta-diketones) under mild and neutral reaction conditions has been developed, which involves the highly selective cleavage of a C-C bond in 1,3-diketones by Yb(OTf)(3) catalyst. For example, the Yb(OTf)(3)-catalyzed cyc/o-condensation of 2-aminobenzamide (la) with 1-phenylbutane-1,3-dione (2c) gave 2-methyl-4(311)-quinazolinone (3a) in 90% yield, together with acetophenone in 65% yield. Ring-opening cyc/o-condensation of 2-aminobenzamides (la) with cyclic 1,3-diketones (2i and 2k-m), except for cyclopentane-1,3-dione (2j), gave 2-substitued 4(3H)-quinazolinones (3i and 3k-m) with one carbonyl group.