Scheme 11 Quinazoline derivatives from 2-aminobenzonitrile using Grignard reagents [179,180]

has been reviewed [3], and was utilized for synthesis of luotonin A (see Sect. 3.5).

Metal Catalyzed Synthesis of Quinazoline Derivatives

Since Watanabe's synthesis of 4(3ff)-quinazolinones in 1993 via transition-metal catalyzed reductive N-heterocyclization [181], several catalytic methods for quinazoline synthesis have been developed [182-186]. For example, palladium-catalyzed cyclocarbonylations of halides with appropriate re-actants provided regioselective synthesis of 4(3H)-quinazolinone derivatives [182] and indoloquinazolines [184]. Also selenium-catalyzed reductive N-heterocyclization to quinazolinones has been developed by Sonoda et al. [183]. Copper-catalyzed heteroannulation with alkynes has been developed as highly region- and stereoselective route to 2-(2-arylvinyl)-1,2,3,4-tetrahydroquinazolin-4-ones 64 by Kundu et al. [185] (Scheme 12). Recently, condensation of anthranylamide with various aldehydes to 4-quinazolinones has been found to give excellent yields in the presence of cupric chloride [186].

For synthesis of quinazoline derivatives, various coupling reactions have been utilized after synthesis of quinazoline-2,4(1H,3H)-diones via palladium-catalyzed oxidative coupling by Hirota et al. [187]. For example, synthesis of diarylquinazolines by iron-catalyzed cross-coupling reaction [188], and diaminoquinazolinones by palladium-catalyzed amination [171] have been developed. Synthetic applications to quinazoline alkaloids are given in Sect. 3.

Scheme 12 Synthesis of 2-(2-arylvinyl)-1,2,3,4-tetrahydroquinazolin-4-ones [185] 2.4.3

Quinazoline Synthesis by Intramolecular Nucleophilic Heterocyclization Reactions

0 0

Post a comment