Tetrabutylammonium Bromide in Water as a Green Media for the Synthesis of Pyrano[2,3-d]pyrimidinone and Tetrahydrobenzo[b]pyran Derivatives.

Tetrabutylammonium bromide (TBAB) was used as a green catalyst for the synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3-d]pyrimidinone derivatives in water as a solvent. Use of nontoxic reaction components, short reaction times, easy work-up and high yields are some important advantages of this method.