Oxalyl chloride → Ethyl 4-chloro-1,6-diethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

Participants

Reaction Steps

Ethyl 1,6-diethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (0.10 g, 0.38 mmol, 1 equivalent, e.g. which can be as prepared in Intermediate 2C) was dissolved in dichloromethane (1.5 ml). Oxalyl chloride (0.07 ml, 0.10 g, 0.76 mmol, 2.0 equivalents) was added in one portion to the stirred solution. The reaction mixture, a solution, was stirred at room temperature for 2 hours, then was heated to 39° C. and stirred for 22.5 hours at this temperature, and then allowed to cool. The reaction mixture was diluted with toluene and then the solvent was removed in vacuo to give a brown oil which solidified on standing at room temperature to yield the title compound as a brown solid (0.086 g, about 80% theory yield). HPLC (5 min generic solvent gradient): TRET about 3.43. Mass Spectrum: Found: MH+ 282.1.

Provenance & Evidence