2-Chlorocyclohexanone → 2-Propyl-4-(4,5,6,7-tetrahydro-benzothiazol-2-yl)-phenol

Participants

Reaction Steps

A suspension of 4-hydroxy-3-propyl-thiobenzamide (5 g, 0.026 mol) (Example 34), 2-chlorocyclohexanone (4.07 g, 0.031 mol), and p-toluenesulfonic acid monohydrate (0.244 g, 1.28 mmol) in anhydrous toluene (100 mL) was heated to reflux in a Dean-Stark apparatus under argon for 12 h. At about 90° C., the mixture became a red orange oil and after 4 h of refluxing, precipitation was observed. The reaction mixture was cooled and diluted with ethyl acetate (50 mL). The organic layer was washed successively with saturated sodium bicarbonate (2×50 mL), water (2×50 mL), brine, dried over sodium sulfate, and concentrated to give the desired product as a tan solid (6.89 g, 98%). LC/MS m/z 274.3 (M+H)+, RT 2.99 min. 1H NMR (400 MHz, DMSO-d6) δ 9.75 (s, 1H), 7.53-7.44 (m, 2H), 6.81 (d, 1H), 2.72-2.68 (m, 4H), 2.54-2.49 (m, 2H), 1.78 (b, 4H), 1.58-1.53 (m, 2H), 0.90 (t, 3H).

Provenance & Evidence