2,3,4,5-Tetrahydro-1H-pyrido[4,3-b]indole-8-carboxylic acid methyl ester synthesis

Yield:1015082-04-8 100%

Reaction Conditions:

with acetyl chloride for 3.5 h;Heating / reflux;

Steps:

1.C

Step C. 2,3,4,5-Tetrahydro-l#-pyrido[4-3b]indoIe-8-methyl carboxylateThe carboxylic acid (87.7 g) was mixed with methanol in a 3L round bottom flask and cooled in an ice bath. Acetyl chloride (100 mL) was slowly added and the ice bath was removed. The mixture was heated at reflux for 3.5 hours. After cooling at room temperature, the mixture was concentrated by evaporation of methanol and the solid was collected by filtration as the desired product (87.3 g, 111 % for two steps) that was still containing ammonium chloride. 1H-NMR (300 MHz, DMSO-J6) ? 11.69 (s, IH), 9.66 (s, IH), 8.16 (s, IH), 7.71 (dd, IH, /= 1.6, 8.6 Hz), 7.41 (dd, IH, J= 0.5, 8.5 Hz), 4.33 (s, 2H), 3.82 (s, 3H), 3.43 (s, 2H), 3.03 (t, 2H, J= 5.9 Hz).

References:

WO2008/36021,2008,A1 Location in patent:Page/Page column 16