Diisopropylamine → N-(4-Chlorobenzyl)-2-formyl-4-methyl-7-oxo-3-{[2-(trimethylsilyl)ethoxy]methyl}4,7-dihydrothieno[3,2-b]pyridine-6-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a cold (−78° C.), stirred mixture of 2.03 g of N-(4-chlorobenzyl)-4-methyl-7-oxo-3-{[2-(trimethylsilyl)ethoxy]methyl}-4,7-dihydrothieno[3,2-b]pyridine-6-carboxamide in 50 mL of dry TBF is added via cannula a solution of LDA, prepared as usual in 25 mL of dry THF from 2.5 mL of diisopropylamine and 5.3 mL of a 2.5 M solution of butyllithium in hexanes. The resulting deeply colored solution is stirred for 5 min at −78° C., then 1.7 mL of dry DMF is added, causing the mixture to solidify. The mixture is allowed to warm to 0° C. whereupon it becomes fluid, and is quenched with 50 mL of 1N HCl. Aqueous workup (CH2Cl2, dil. HCl) followed by flash chromatography on silica gel using 30-40% EtOAc in CH2Cl2 affords 1.56 g of the title compound as a yellow solid. Recrystallization from EtOAc provides pale yellow crystals.

Provenance & Evidence