Anthranilic Acid → Acetanthranil

Participants

Reaction Steps

4-iodo-2-methylbenzenamine 24 (233 mg, 1 mmol) on reaction with 2-ethynyl-6-methoxynaphthalene (25c, 182 mg, 1 mmol) by employing Sonagashira coupling conditions using Pd(PPh3)4 (69.3 mg, 0.06 equiv) as catalyst, CuI (22.8 mg, 0.12 equiv) as cocatalyst, butyl amine (261 mg, 3 equiv) as base and ether as solvent and kept the reaction for 6 h. After completion of the reaction as indicated by TLC and the reaction mixture is extracted into ether (4×25 mL) from the aqueous layer and concentrated in vacuo. The compound was further purified by column chromatography using 60-120 silica gel (ethyl acetate/hexane, 1:9) to obtain 4-((6-methoxynaphthalen-2-yl) ethynyl)-2-methyl benzenamine (26c) as pure product. Anthranilic acid (27, 137 mg, 1 mmol) on reaction with acetic anhydride at 150° C. and reflux for 30 min, after completion of reaction aqueous sodium bicarbonate solution is added and extracted in ethyl acetate (4×25 mL) from the aqueous layer and concentrated in vacuo afforded 2-methyl-4H-benzo[d][1,3]oxazin-4-one compound (28) as pure product. To a stirred solution of 4-((6-methoxynaphthalen-2-yl)ethynyl)-2-methylbenzenamine (26c) with 2-methyl-4H-benzo[d][1,3]oxazin-4-one (28, 161 mg, 1 mmol) in acetic acid and reflux for 8 h After completion of the reaction as indicated by TLC. then the reaction mixture was quenched with NaHCO3 and extracted in ethyl acetate (4×25 mL) from the ice cold aqueous layer and dried over anhydrous Na2SO4 afforded 3-(4-((6-methoxynaphthalen-2-yl)ethynyl)-2-methylphenyl)-2-methylquinazolin-4(3H)-one (29c). Reaction of 3-(4-((6-methoxynaphthalen-2-yl)ethynyl)-2-methylphenyl)-2-methylquinazolin-4(3H)-one (29c, 430 mg, 1 mmol) with 3,4,5-trimethoxybenzaldehyde (30l, 196 mg, 1 mmol) was taken in acetic acid Then the resulting mixture was stirred under reflux conditions for 8 h and then the reaction mixture was quenched with NaHCO3 and extracted in ethyl acetate (4×25 mL) from the ice cold aqueous layer and dried over anhydrous Na2SO4. The resulting product (61) was purified by column chromatography employing EtOAc/Hexane as an eluent.

Provenance & Evidence