Isopropylamine → Ethyl 2-chloro-4-isopropylcarbamoyl-thiazole-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 2-chloro-5 (ethoxycarbonyl)-1,3-thiazole-4-carboxylic acid (Intermediate 7, 1.0 g, 4.2 mmol) in dry dichloromethane (20 mL) was added oxalyl chloride (0.73 mL, 8.4 mmol) and 2 drops of dry dimethylformamide. The reaction mixture was refluxed to 45° C. for 1½ h. The reaction mixture was cooled to room temperature, and then evaporated to dryness under reduced pressure. The residue was dissolved in dry dichloromethane (20 mL) and cooled to 0° C., then 2,6-lutidine (0.493 mL, 4.237 mmol) was added followed by addition of isopropyl amine (0.360 mL, 4.237 mmol). After completion of the reaction, the reaction mixture was concentrated to dryness and the residue was extracted with ethyl acetate (2×50 mL). The organic layer was washed with 1 N hydrochloric acid (1×50 mL), then dried over anhydrous sodium sulfate and concentrated under vacuum to afford 1.13 g (96%) of the title compound as a thick syrup. NMR: 1.26 (d, 6H), 1.38 (t, 3H), 4.24 (m, 1H), 4.40 (q, 2H), 7.51 (br s, 1H).

Provenance & Evidence