A successful simple application of the quinazolinone annelation is the short step synthesis of rutecarpine 16, an indolopyridoquinazoline alkaloid of Evodia rutaecarpa, from 2,3,4,9-tetrahydro-1H-^-carbolin-1-one 80 via 2-azidobenzoyl derivative 81 (Scheme 18) [222]. Even after Kametani's practical iminoketene/amides condensation synthesis [227,228], many other synthetic routes to 16 and related systems utilizing Fischer indole synthesis [223-225] or cyclocondensation [65,226,229,230], etc. have been developed; among these syntheses, above quinazolinone annelation route is one of the most facile and concise one. Recently very concise Pd-assisted biaryl coupling route to 16 as well as to luotonin A (26) and B (27) has been developed by Harayama et al. [231,232] (see Sect. 3.5).

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