Seyyed Jalal Roudbaraki, Sadaf Janghorban and Majid Ghashang * Pages 421 - 427 ( 7 )
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- amino-4,5-dihydro-4-arylthiochromeno[4,3-b]pyran-3-carbonitriles, (8Z)-2-amino-8-arylidene-4,5, 7,8-tetrahydro-4-arylthiopyrano[4,3-b]pyran-3-carbonitriles, 4-aryl-3,4,5,6-tetrahydrobenzo[h]quinazoline- 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.
HSBM technique, 4H-pyran, ZnAl2O4, benzo[h]thiazolo[2, 3-b]quinazoline thiochromeno[4, 3-b]pyran, 3- benzylidenethiochroman-4-one, thiopyrano[4, 3-b]pyran.
Department of Chemistry, Lahijan Branch, Islamic Azad University, Lahijan, Department of Chemistry, Najafabad Branch, Islamic Azad University, P.O. Box: 517, Najafabad, Department of Chemistry, Najafabad Branch, Islamic Azad University, P.O. Box: 517, Najafabad