Trimethyl orthoformate → Tert-butyl 4-((2-chloro-4-morpholinothieno[3,2-d]pyrimidin-6-yl)methyl)piperazine-1-carboxylate

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Reaction Steps

A mixture of 2-chloro-4-morpholin-4-yl-thieno[3,2-d]pyrimidine-6-carbaldehyde 10 (3.5 g), 1-BOC-piperazine (2.76 g) and trimethylorthoformate (4.05 mL) was stirred in 1,2-dichloroethane (300 mL) for 1 hr at room temperature. To this was added sodium triacetoxyborohydride (3.92 g) and the reaction mixture was stirred for 24 hours at room temperature. The mixture was then quenched with brine, extracted with dichloromethane, dried (MgSO4) and the solvent removed in vacuo. The residue was purified using flash chromatography to yield 4-(2-chloro-4-morpholin-4-yl-thieno[3,2-d]pyrimidin-6-ylmethyl)-piperazine-1-carboxylic acid tert-butyl ester (3.4 g). Treatment with HCl in dichloromethane/methanol yielded 4-(2-chloro-6-(piperazin-1-ylmethyl)thieno[3,2-d]pyrimidin-4-yl)morpholine 30.

Provenance & Evidence