Trimethyl borate → 3-Methyl-4-nitrobenzyl alcohol

Participants

Reaction Conditions

Reaction Steps

A flask purged with nitrogen was charged with 3-methyl-4-nitro-benzoic acid (72.5 g, 0.400 mol), trimethyl borate (166.2 g, 1.600 mol) and dry tetrahydrofuran (1449 mL). A solution of borane dimethyl sulfide complex (63.8 g, 79.8 mL, 0.840 mol) was added drop-wise to the stirred batch at 20-35° C. over at least 30 min. An exotherm and effervescence were observed during the addition. The mixture was stirred at 65° C. for at least 6 h or until in-process HPLC analysis showed that conversion was greater than 97%. Reaction was quenched at 20-40° C. with cooling by drop-wise addition of methanol (46 mL) followed by aq 5 N hydrochloric acid (144 mL) over at least 30 min. Exotherm and effervescence were observed during the quench. After stirring the batch at 50° C. for at least 1 h, it was concentrated under reduced pressure to a volume of 360 mL. The concentrated batch was washed with water (453 mL) and the solids were collected on a filter. The wet filter cake was dissolved in CH2Cl2 (2170 mL) at and the resulting solution dried over anhydrous magnesium sulfate (36 g). The dried filtrate solution containing the title compound (˜67 g, 100% yield) was used directly in the preparation of 3-methyl-4-nitro-benzaldehyde.

Provenance & Evidence