One-Pot Synthesis of 2-Amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo- 4H-5,6,7,8-tetrahydrobenzo[b]pyran in Aqueous Medium;

K_2CO_3 as the base,aromatic aldehyde,malononi- trile and 5,5-dimethyl-1,3-cyclohexanedione were condensed to form tetrahydrobenzo[b]-γ-pyran derivatives in a solvent-free one-pot process under grinding.

Catalyst-free synthesis of 2-amino-7,7-dimethyl-5-oxo-4-aryl-4H-chromene-3-carbonitrile-5,6,7,8-tetrahydrobenzo[b]pyran(2) in water is described.

Recently , Compouds containing Benzo[b]pyran structure is the hotspot of new drugs development, which possess antitumor, choleretic treatment and eliminating urolith, anticoagulation, anti-osteoporosis, anti-inflammatory, anti-fungus, hemangiectasis, reducing blood sugar , antivirus, anti-schistosomiasis, and so on.

Owing to the special structure and high reactivity of 2-(benzo[d]thiazole-2-yl)- acetonitrile andβ-(2-chloroaroyl)-heterocyclic ketene aminals, we herein developed an excellent strategy for for the synthesis of 4H-benzo[b]pyrans, tetrahydroimidazo -[1,2-a]pyridines and 1,8-naphthyridines derivatives.