HCID 66827699, compound → HCID 69810089, compound

Participants

Reaction Steps

302 mg of N′-[2-(3,5-difluorophenyl)-2-oxoacetyl]-4-benzyloxy-2-ethyl-3-methylbenzohydrazide (B3) are dissolved in 25 ml of tetrahydrofuran. This solution is added dropwise over the course of 5 min to a solution of 49 μl of borane/dimethyl sulfide complex and 55 μl of (R)-methyloxazaborolidine [(R)-Me-CBS, 1-1.5 M in toluene) in 17 ml of tetrahydrofuran at a temperature of (−)78° C. The cooling bath is subsequently removed, and the solution is stirred for 6 h, during which the reaction solution warms to room temperature: 100 ml of water are then added, and the mixture is extracted three times with 150 ml of ethyl acetate each time. The combined organic phases are washed with 40 ml of each of water, 0.1 M HCl and sat. NaCl solution, dried over NaSO4, filtered off with suction and evaporated to dryness. The residue is purified by means of preparative HPLC (solvent gradient: water/1-50% by vol. of acetonitrile), giving 63 mg of the title compound as colourless, amorphous solid. MS: 932 (2M+Na+); TLC: Rf=0.56 (cyclohexane/methyl tert-butyl ether 1:4, parts by volume).

Provenance & Evidence