2,3 Dihydrofuro[3,2 c]coumarin 3 one reacts with aromatic amines in two pathways, depending on the solvent. The reactions in ethanol afford its enamines, while the use of acetic acid favors the formation of enamines of the 2,3 dihydrofuro[3,2 c]coumarin 3 one dimer. Electronic absorption spectroscopy in different solvents revealed that the enamines obtained can undergo tautomeric transformations. The product of a reaction of 2,3 dihydrofuro [3,2 c]coumarin 3 one with 4 bromoaniline exists in the enamine form (X ray diffraction data).
2,3 Dihydrofuro[3,2 c]coumarin 3 one reacts with arylhydrazines via two routes. The corresponding hydrazones are formed from arylhydrazines in alcohol and nitrophenylhydrazines in acetic acid or toluene. With phenylhydrazine and para tolylhydrazine in toluene, 2,3 dihydrofuro[3,2 c]coumarin 3 one reacts unusually undergoing dihydrofuran ring open ing and the formation of the corresponding 3 (2 imino 1 (2 arylhydrazinyl)ethylidene) chromane 2,4 diones. The solvatochromic properties of the synthesized compounds were studied using electronic absorption spectra and quantum chemical calculations.
Tautomeric transformations of a series of 4 methyl 8 (R phenylazo)dihydrofuro[2,3 h] coumarin 9 ones were studied by 1 H NMR, IR, electronic absorption spectroscopy, mass spectrometry, and quantum chemistry methods. The obtained results suggest that (p R phenyl) derivatives exist in the quinone hydrazone form, while (o R phenyl)derivatives exist as a mixture of quinone hydrazone and azo enol tautomers with domination of the former. The anti quinone hydrazone tautomers with a strong intramolecular hydrogen bond are more favorable than the syn quinone hydrazone tautomers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.