ethyl 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-2-carboxylate synthesis

Yield:900156-55-0 92%

Reaction Conditions:

Stage #1: 7-ethoxycarbonyloxy-3,4-dihydro-1H-isoquinoline-2-carboxylic acid ethyl esterwith ethanol;water;potassium carbonate at 20; for 5 h;
Stage #2: with hydrogenchloride in water; pH=7;

Steps:

1.22.b

(b) 7-Hydroxy-3,4-dihydro-1H-isoquinoline-2-carboxylic acid ethyl ester A mixture of 11 mmol 7-ethoxycarbonyloxy-3,4-dihydro-1H-isoquinoline-2-carboxylic acid ethyl ester, 14 mmol potassium carbonate, 0.6 ml water and 200 ml ethanol is stirred for 5 hours at room temperature. The reaction mixture is concentrated, diluted with 100 ml water and the pH adjusted to 7 by addition of diluted hydrochloric acid. Extraction with diethyl ether and purification by chromatography (SiO₂; ethyl acetate/cyclohexane 1:1) gives the title compound. Yield=92%.

References:

US2006/167023,2006,A1 Location in patent:Page/Page column 17