Enaminones in heterocyclic synthesis: a novel route to tetrahydropyrimidines, dihydropyridines, triacylbenzenes and naphthofurans under microwave irradiation.
Condensation of phthalimidoacetone (1) with DMFDMA (N,N-Dimethylformamide dimethyl acetal) has afforded enaminone 2. Refluxing 2 with equimolecular amounts of benzaldehyde and urea in acetic acid afforded a mixture of tetrahydropyrimidine 5 and the dihydropyridine 6. Compound 2 undergoes self-condensation on heating in acetic acid or under microwave irradiation in presence of acidic zeolite to give 1,3,5-triacylbenzene 9. Reacting enaminone 11a with naphthoquinone 15 afforded the naphthofuran 18. The possible formation of the aldehyde 19 was excluded based on an HMQC experiment, which revealed that the carbonyl carbon is not linked to any hydrogen.
Al-Mousawi
Saleh Mohammed
SM
Department of Chemistry, Faculty of Science; Kuwait University, P.O. Box 5969 Safat 13060, Kuwait. saleh.almousawi@yahoo.com
El-Apasery
Morsy Ahmed
MA
Elnagdi
Mohamed H
MH
D001554:Benzene / Q000138:chemical synthesis* / Q000737:chemistry; D004095:Dihydropyridines / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006574:Heterocyclic Compounds, 2-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D008872:Microwaves; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry
D004095:Dihydropyridines; D005663:Furans; D006574:Heterocyclic Compounds, 2-Ring; D011743:Pyrimidines; D001554:Benzene