Hydrochloric Acid → HCID 5358230, compound

Participants

Reaction Conditions

Reaction Steps

This example describes reduction of ansamitocins with LiAl(OMe)3H using water followed by aqueous HCl. Ansamitocins (200 mg, 0.32 mmol) were weighed into a 25 mL round bottomed flask. Tetrahydrofuran (1.0 mL) was added to the flask with stirring, and the flask was cooled in a −42° C. cooling bath. After 10 min, a solution of 0.67 M LiAl(OMe)3H in tetrahydrofuran (3.8 mL, 2.52 mmol) was added dropwise by syringe. The bath temperature was maintained between −34° C. and −42° C. throughout the addition. After addition was complete, the reaction was stirred for 2 hours at between −32° C. and −37° C. 1 mL of deionized water was added dropwise to the reaction. After a 30 min holding period, 2 mL of 3 M HCl and 10 mL of ethyl acetate were quickly added to the flask. The cooling unit was turned off, and most of the aluminum byproducts went into solution. The contents were transferred to a separatory funnel and mixed well. The organic layer was retained and washed with 2 mL of saturated sodium chloride. The organic layer was dried over anhydrous sodium sulfate, and solvent was removed by rotary evaporation. The residue was purified by silica chromatography using a mobile phase of dichloromethane:methanol 95:5 (v:v) to give 117 mg of maytansinol (66% yield by weight).

Provenance & Evidence