Aim and Objective: The aim of this paper is to introduce HSBM as a green and
environmentally friendly technique for the synthesis of thiochromeno[4,3-b]pyran and
benzo[h]thiazolo[2,3-b]quinazoline derivatives over ZnAl2O4 nanopowders as an efficient catalyst.
Materials and Methods: ZnAl2O4 nanopowders were synthesized via a co-precipitation of
Zn(NO3)2 and Al(NO3)3 salts and were characterized by XRD, FE-SEM, TEM and DLS
techniques. The as-prepared ZnAl2O4 nano-powders have been used as a catalyst on the synthesis
of pyran nucleus using high-speed ball milling (HSBM) technique. The structure of products was
confirmed with NMR analysis.
Results: ZnAl2O4 exhibits a cubic crystal structure (Space group: Fd-3m) with the average
crystallite size of 41 nm. The average particle size of ZnAl2O4 nano-powders determined by DLS
technique is 55 nm. The catalytic activity of nano-powders was examined on the synthesis of 2-
2(1H)-thiones and 4-aryl-1,3,4,5-tetrahydro-2H-thiochromeno[4,3-d]pyrimidine-2-thione
derivatives. All products were obtained in high yields with short reaction times.
Conclusion: ZnAl2O4 nanopowders were prepared via a cost-effective co-precipitation method and
showed good potential for the synthesis of 4H-pyran analogous in good yields. The salient
advantages of HSBM technique include environmentally friendly with reduced solvents, is a
simple technique and has low energy costs.