Bendamustine Hydrochloride → HCID 118307179, compound

Participants

Reaction Steps

A 250 mL three neck round bottom flask equipped with a stir bar, thermocouple, cooling bath, addition funnel and nitrogen in/outlet was charged with 10 g (25.3 mmol) of bendamustine hydrochloride, 10.6 g (27.8 mmol) of HATU and 100 mL of DMF. The batch was cooled to 1.9° C. where 8.8 mL (6.54 g, 50.6 mmol) of DIPEA was added over 2 minutes. The reaction exothermed to 9° C. and became orange. A solution of 3.57 g (25.6 mmol) of L-alanine methyl ester hydrochloride and 6.2 mL (4.57 g, 35.4 mmol) of DIPEA in 20 mL of DMF was added drop-wise over 10 minutes at 4.9-5.7° C. The reaction was slowly warmed to RT over one hour and stirred for three hours at which time an in process assay indicated the reaction was complete. The batch was quenched onto 400 mL of 1:1 ethyl acetate/DI water. The layers were separated, the organic was washed with 10% sodium hydrogen phosphate (1×200 mL), 8% sodium bicarbonate 91×200 mL) and brine (1×200 mL), before drying over sodium sulfate, filtering and evaporating to dryness in vacuo. The residue was purified by chromatography using 100 g of silica gel 60, 230-400 mesh, eluting with 1% MeOH/MDC (3 L), 2.5% MeOH/MDC (1 L) and 5% MeOH/MDC (500 mL) collecting ˜100 mL fractions. The product containing fractions were combined and concentrated to dryness in vacuo to yield 7.1 g (16.0 mmol, 63.3%) of the desired product as a white solid with an HPLC purity of 97.4A %. 1H NMR (400 MHz, DMSO-d6) δ 8.25 (d, J=6.92 Hz), 1H), 7.40 (d, J=8.84 Hz, 1H), 6.92 (d, J=2.2 Hz, 1H), 6.86 (dd, J=2.32, 8.88 Hz), 4.25 (q, 1H), 3.72 (s, 8H), 3.71 (s, 3H), 3.62 (s, 3H), 2.87 (t, J=7.48 Hz, 2H), 2.25 (t, J=7.52 Hz, 2H), 1.99 (m, 2H), 1.26 (d, J=7.32 Hz, 3H).

Provenance & Evidence