2-BENZOYL-1,2,3,4-TETRAHYDRO-ISOQUINOLINE-3-CARBOXYLIC ACID synthesis

Yield:93316-40-6 77%

Reaction Conditions:

Stage #1: 1,2,3,4-tetrahydro-isoquinoline-3-carboxylic acid ; hydrochloridewith sodium hydroxide in acetone at 20;
Stage #2: benzoyl chloridewith sodium hydroxide in acetone at 20; pH=> 10;
Stage #3: with hydrogenchloride in water; pH=5 - 6;

Steps:

4.3. 2-Propionyl-1,2,3,4-tetrahydroisoquiniline-3-carboxylic acid (18b)

General procedure: To a suspension of 1,2,3,4-tetrahydroisoquinoline-3-carboxylicacid hydrochloride (17, 10 g, 46.8 mmol) in acetone (60 mL) was added 2 N NaOH (40 mL) solution at room temperature. The clear solution obtained then added dropwise into a solution of propionyl chloride (5.2 g, 57 mmol) in acetone (20 mL) at room temperature, simultaneously 2 N NaOH was added dropwise and pH maintained above 10. The reaction mixture was stirred at room temperature for 2 h, the solvent was evaporated under reduce pressure. The solution was acidified to pH 5-6 with 3 N HCl. The white solid separated, filtered it and dried to give 18b 9 g, yield 87%.

References:

Chaniyara, Ravi;Kapuriya, Naval;Dong, Huajin;Lee, Pei-Chih;Suman, Sharda;Marvania, Bhavin;Chou, Ting-Chao;Lee, Te-Chang;Kakadiya, Rajesh;Shah, Anamik;Su, Tsann-Long [Bioorganic and Medicinal Chemistry,2011,vol. 19,# 1,p. 275 - 286] Location in patent:experimental part