Diisopropylethylamine → (4-Iodo-2-methoxyphenyl)-5H-pyrrolo[2,1-c][1,4]benzodiazepin-10(11H)-ylmethanone

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Reaction Steps

A suspension of 4-iodo-2-methoxybenzoic acid of Step B (2.5 g, 9.0 mmol) in thionyl chloride (10 mL) was heated at reflux for 1 hour. After cooling, the thionyl chloride was removed in vacuo. The residue was dissolved in toluene and concentrated in vacuo to give the crude acid chloride as a brown solid. The acid chloride was then dissolved in dichloromethane (10 mL) and slowly added to a solution of 10,11-dihydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine (1.75 g, 9.5 mmol) and N,N-diisopropylethyl amine (3.4 mL, 19.5 mmol) in dichloromethane (20 mL). After stirring for 2 hours, the reaction was quenched with water. The organic layer was washed with 1 N hydrochloric acid, 1 N sodium hydroxide and brine, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give a yellow foam. Purification by flash chromatography on silica gel using a solvent gradient of 15 to 25% ethyl acetate in hexane provided 3.6 g of title product as a white foam, which was redissolved in dichloromethane and evaporated to dryness prior to use in the next step.

Provenance & Evidence