Synthesis of novel dihydropyridine, dihydropyrimidine, dithioacetal and chalcone derivatives from formylchromones.

Condensation of 6-Formylfurochromone (4,9-dimethoxy-5-oxo-5H-furo[3,2-g][1]benzopyran-6-carbaldehyde) 5a and malononitrile without solvent afforded (2E)-2-cyano-3-(4,9-dimethoxy-5-oxo-5H-furo[3,2-g]benzopyran-6-yl) acrylamide 8 at hydrolysis with dilute HCL. 2,6-Diamino-4-(4,9-dimethoxy-5-oxo-5H-furo[3,2-g]benzopyran-6-yl)-1,4-dihydropyridine-3,5-dicarbonitrile 9 and 6-(2,6-diacetyl-3,5-dimethylcyclohexa-2,5-dien-1-yl)-4,9-dimethoxy-5H-furo[3,2-g][1]benzopyran-5-one 10a,b were synthesized by one-pot cyclocondensation reaction of formyl 5a, malononitrile and ammonium acetate/or ammonium hydroxide/or aniline. The reaction of formyl 5a, malononitrile/acetylacetone (Thio) urea/guanidine HCL to give 6-amino-4-(4,9-dimethoxy-5-oxo-5H-furo[3,2-g][1]benzopyran-6-yl)-2-methylene-1,2,3,4-tetrahydropyrimidine-5-carbonitrile compounds 11a,b, 6-(2-amino-5,6-dimethyl-1,4-dihydropyrimidin-4-yl)-4,9-dimethoxy-5H-furo[3,2-g][1]benzopyran-5-one 12a,b. Condensation of formylfurochromone 5a with thiol compounds afforded 6-isopropyl-4-methoxy-9-(methoxy Ia or methyl Ib)-5H-furo[3,2-g][1]benzopyran-5-one 13a-f; 6-(1,3-dithiolan-2-yl)-4-methoxy-5H-furo[3,2-g]chromen-5-one 14a,b; 7-hydroxy-6-isopropyl-5-methoxy-2-methyl-4H-benzopyran-4-one 5a-c; 6 hydroxy-7-[mercapto(methylthio)methyl-8-methoxy-3-methylnaphthalen-1(4H)-one 16, respectively. Formylfurochromones 5a-c were reacted with different substituted of acetyl compounds (khellinone, 2-acetyl pyrrol, 3-acetyl coumarin, methyl-2-thienyl ketone and p-aminoacetophenone respectively) to proceed 4-methoxy-9-(methoxy Ia or methyl Ib)-6-(1E)-3-oxobut-1-enyl]-5H-furo[3,2-g][1]benzopyran-5-one 17, 5-methoxy-2-methyl-6[(1E)-3-oxobut-1-enyl]-4a,5,8,8a-tetrahydro-4H-benzopyran-4-one 18a-d, 4,9-dimethoxy-6-[(1E)-3-methoxyprop-1-enyl]-5H-furo[3,2-g][1]benzopyran-5-one-N-methylene-N-phenylamine-6-(iminomethyl)-4,9-dimethoxy-5H-furo[3,2-g][1]benzopyran-5-one 19.