Methanol → 4-(5-Cyano-7-isopropylbenzo[d]oxazol-2-yl)benzoic acid

Participants

Reaction Conditions

Reaction Steps

To a 5-l, round-bottom flask fitted with a stir bar and a Claisen adapter fitted with a thermocouple and a nitrogen line was added was added methyl 4-(5-cyano-7-isopropyl-1,3-benzoxazol-2-yl)benzoate (40.5 g, Step B) tetrahydrofuran (1.25 l), methanol (630 ml), water (315 ml), and lithium hydroxide monohydrate (10.7 g). The mixture was heated to 50° C. and stirred at this temperature for 1 h. The mixture was then cooled and concentrated to a thick slurry. 1N HCl (3.2 l) was added and an off-white solid formed. The mixture was stirred for 5 min and then filtered, washing with water (2×500 ml). The solid was transferred to a 2-l round-bottom flask, concentrated from toluene (1 l) and then dried in vacuo. Mass spectrum (ESI) 307.0 (M+1). 1H NMR (500 MHz, DMSO-d6): δ 8.69 (d, J=7.5 Hz, 2H), 8.28 (s, 1H), 8.16 (d, J=8.0 Hz, 2H), 7.81 (s, 1H), 3.46 (septet, J=6.5 Hz, 1H), 1.40 (d, H=7.0 Hz, 6H).

Provenance & Evidence