3-(3'-Hydroxyphenyl)propionic acid → 3-(2-Benzimidazol-2-ylethyl)phenol

Participants

Reaction Conditions

Reaction Steps

A 100 mL flask fitted with a stir-bar and a condenser was charged with 1,2-phenylenediamine (3.42 g, 31.6 mmol), 3-hydroxyhydrocinnamic acid (5.25 g, 3.16 mmol), and 4M HCl (50 mL). The mixture was heated in a 135° C. bath overnight. The mixture was cooled in an ice bath, and the precipitate was filtered and rinsed with H2O (5 mL). The solid was suspended in saturated NaHCO3 (75 mL). 50% aq NaOH was added until pH 11 was attained, and then another portion of saturated NaHCO3 (75 mL) was added. The suspension was stirred overnight. The solid was filtered, pressed with rubber dam, and rinsed with H2O (2×10 mL). The resultant material was dried to give 6.05 g of 69 as a white solid (80%). 1H NMR (60 MHz, CDCl3): δ 7.6-7.4 (m, 2H), 7.4-7.0 (m, 3H), 6.9-6.6 (m, 3H), 5.2 (s, 2H), 3.1 (s, 4H) ppm. HPLC analysis (35:10:55 H2O:A1:MeOH) showed a purity of greater than 99% with a retention time of 3.1 min.

Provenance & Evidence