A green process PEG‐600 mediated on‐pot, alternative synthesis of 3‐methyl‐2‐(((1‐methyl‐1H‐benzimidazole‐2‐YL) sulfonyl) methyl) quinazolin‐4(3H)‐one

Abstract

Condensation of 2‐((1H‐benzo[d]imidazol‐2‐yl)thio)acetic acid (1) with anthranilamide (2) in PEG‐600 (polyethylene glycol), at 100 oC for 3hr. gave 2‐(((1H‐benzo[d]imidazol‐2‐yl)thio)methyl)quinazolin‐4(3H)‐one (3). Treatment of 3 with DMS, DES and Ph‐CH2‐Cl, individually in PEG‐600, at RT for 1 hr. without using any base, followed by easy process resulted in 4 (a‐c). The later on reaction with H2O2 in PEG‐600, for 3 hr, without using any base, followed by simple processing resulted in 5 (a‐c). Alternatively, 5 (a‐c) the sequence of reactions could be prepared by tandem procedure with good yields. Thus novel quinazolinone products have been prepared with new synthetic routes and strategies by using PEG‐600 as solvent, in polyethylene glycol (PEG‐600) in four routes. i.e. (tandem‐1, tandem‐2, stepwise‐1 and stepwise‐2) Probably, this is the first case of four variable but identical end‐products‐ giving tandem syntheses, under green conditions, of 5 (a‐c). Obviously, as figures pointed out, tandem‐1 route gave good yields compared to the stepwise routes. In this process PEG‐600 recycled and reused.