An innovative synthesis of tertiary hydroxyl thieno[2,3-d]pyrimidinone skeleton: natural-like product from the tandem reaction of o-aminothienonitrile and carbonyl compound

ZnCl2-promoted domino reaction of 2-hydroxybenzonitriles with ketones for synthesis of 1,3-benzoxazin-4-ones

“… 10 During the past decade, we have synthesized many fused heterocycles employing the modified Friedländer cyclocondensation of o -aminonitriles with carbonyl compounds (PDF conversion). 11 Analogously, we speculated that 2,3-dihydro-4 H -1,3-benzoxazin-4-ones would be provided by the similar cyclocondensation of salicylonitrile instead of 2-aminobenzonitrile condensed with carbonyl compounds ( Scheme 2 ). There is no report on the synthesis of 2,3-dihydro-4 H -1,3-benzoxazin-4-ones via heterocyclic condensation of 2-hydroxybenzonitrile with carbonyl compounds.…”

Recent advances in the chemistry of thieno[2,3-b]pyridines 1. Methods of synthesis of thieno[2,3-b]pyridines

“…When Lewis acids (AlCl 3 or ZnCl 2 ) are used, trace amounts of thienopyrimidines 94 were also found among the reaction products 169. The lat-ter are products of the competing tandem Pinner-Dimroth reaction and subsequent photooxidation and become the major reaction products under EtONa catalysis (Scheme 38).In the Friedländer reaction with Gewald´s thiophenes β-ketophosphonates,170,171 heterocyclic ketones and 1,3-diketones, 172 methylene active nitriles (under basic catalysis conditions), 173,174 and -haloketones 175 can react instead of ketones or ethyl acetoacetate.…”