31% | at 150℃; for 0.116667h;Microwave irradiation; | General procedure: Amide formation: (0088) The acid chloride (1 eq) formed on the corresponding 2-aminobenzothiazole (1 eq) is added introduced in a microwave vial. The vial is introduced in the microwave reactor and heated to the temperature for the time indicated in each case. Dichloromethane (50 mL) is added and extracted with a 0.1 M HCl (50 mL) solution. Next, the organic phase is washed with saturated NaHC03 solution (50 mL) and then with saturated NaCl (50 mL) solution. The organic phase is dried over anhydrous MgS04 and the solvent removed under reduced pressure. The residue obtained was purified by flash column chromatography using Isolera One equipment. In all cases a mixture of hexane and ethyl acetate was used as eluent. All the acid chlorides required for the synthesis of the amide derivatives were synthesised in situ except: 2-(4-chlorophenyl)acetyl chloride, 2-(2,5-dimethoxyphenyl)acetyl chloride and 2-phenylbutanoyl chloride, which were purchased directly from the company Sigma Aldrich. N-(6-trifluoromethylbenzothiazole-2-yl)-2-(2,5-dimethoxyphenyl)acetamide (29): (0105) Reagents: 2-(2,5-dimethoxyphenyl)acetyl chloride (246 mg, 1.2 mmol), 2-amino-6-trifluoromethylbenzothiazole (250 mg, 1.2 mmol). Reaction conditions: 7 min under microwave irradiation at 150°C. Purification by flash column chromatography using hexane/ethyl acetate (3:1) to obtain a beige solid. Yield: 141.7 mg, 31percent. Mp. 146°C-147°C 1H NMR (300 MHz, DMSO-d6) 5: 8.26 (d, J = 24.7 Hz, 1 H), 7.63 (dd, J = 32.9, 7.4 Hz, 2H), 6.82 (dd, J = 30.0, 9.1 Hz, 3H), 3.68 (s, 8H). 13C NMR (75 MHz, DMSO-d6) delta: 174.0, 165.95, 152.9, 152.6, 151.5, 132.5, 125.9, 121.9 (d, J = 2.25 Hz), 121.6 (d, J = 37.2 Hz), 119.2, 118.8 (d, J = 3.6 Hz), 117.4, 111.7 (2C), 56.0, 55.3, 38.4. HPLC purity: >99percent. MS (ES) m/z: 397 [M+H]+. |