Ar = 2-chlro-3-pyridyl, 4-CF3C6H4, 4-MeOC6H4, C6H5 etc

Scheme 13 Intramolecular heterocyclization route to 3-aryl-4(3H)-quinazolinones [189]

gave 68 in 46-94% yields after two-step process as shown but a tedious chromatographic separation was required. Method B based on the protocol in a patent literature [195] using modified conditions provided more efficient and convenient route to 68 for improved yields and easier work-up. The ester group of 68 was converted to the corresponding carboxamides. Other unique quinazoline syntheses by defluorinative nucleophilic cyclizations have been reported by Hynes et al. [196], Kotsuki et al. [197], and by defluorinative rearrangement by Uneyama et al. [198]. Synthesis of aminoquinazolines by heterocyclization was developed also by several groups [199-201].

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