3-Formylchromones as diverse building blocks in heterocycles synthesis

Synthesis of imidazo[1,2-a]pyridin-chromones by a MW assisted Groebke–Blackburn–Bienaymé process

“…For example the 3-formylchromone is an excellent 1,2 and 1,4 acceptor. 6 This feature make it a suitable carbonylic reagent for multicomponent reactions (MCR), 7 which are one pot processes with a wide range of applications mainly in both, diversity oriented synthesis and combinatorial chemistry. 8…”

Chemistry of 3-carbonyl-2-methyl-4-oxo-4H-1-benzopyrans

“…Because of these functionalities (activated olefinic bond, electrophilicity at three centres and nucleophilicity at the 2-methyl group), the chemistry of 2-methylchromones 1-5 is more varied than that of the lower homologues 6. Of the several review articles on chromones, the latest one on 2-methylchromone 8 1 , two on the nitrile 7a 2,3 and three on 3-formylchromone 6a [4][5][6] are noteworthy. In contrast, a full, complete and up-to-date survey on the chemistry of the title chromones 1-5 is still lacking.…”

Chemistry and application of 4-oxo-4H-1-benzopyran-3-carboxaldehyde

“…This aspect mainly studied before 2000 has been the subject matter of seven publications well comprehended in a recent review. 3 ChrCHO has been reacted with methoxy(methyl)pentacarbonyltungsten carbene complex 122 in the presence of TMSCl and triethylamine; the carbanion generated from the carbene complex 122 condenses with the pyrylium salt generated from 1 and TMSCl to give the benzopyran Fischer carbene complex 123. The reaction of 1 with phenylacetic acid when conducted in the presence of t-BuOK under MWI, however, takes a different course; here initial condensation followed by decarboxylation produces only the E-isomeric form of 3-styrylchromone (E-137).…”

“…Synthesis of 3-hydrazinochromone 211 from 1 and azidodicarboxylate 208 (E = CO 2 Et or CO 2 Me) in the presence of DABCO (here written as NR 3 ) involves an aza-Baylis-Hillman type reaction (→209→210) followed by deformylation (Scheme 19). 172 ChrCHO and 208 in the presence of PPh 3 take a different reaction course (vide section 6.5).…”