HCID 10872275, compound → Talampanel

Participants

Reaction Steps

(R)-7-acetyl-8,9-dihydro-8-methyl-5-(4-nitrophenyl)-7H-1,3-dioxolo[4,5-h][2,3]benzodiazepine (38.93 g) was hydrogenated in 730 mL (19 volumes) of 2B-3 ethanol using 7.79 g of 10% palladium on carbon and 1 atmosphere of hydrogen. When HPLC analysis indicated that starting material had been consumed, the catalyst was removed by filtration and the filtrate was evaporated to afford 38.7 g of crude product. The crude product was dissolved in 220 ML (5.7 volumes) of 1:1 water/ethanol by heating to reflux. The mixture was allowed to cool and the product precipitated near room temperature. The resulting thick, poorly stirring, slurry was stirred at room temperature and then cooled in an ice/water bath. The solid was isolated by filtration and dried in a vacuum oven at 55° C. overnight to afford 31.6 g of purified product. A second recrystallization using the same conditions afforded 28.7 g (30%) of product after drying under vacuum for 3 days at 65° C. and 3 days at room temperature. The product dried very slowly and 1.6% ethanol was still on the sample at this point. Analysis by X-ray diffraction (XRD), solid state NMR (SSNMR) and differential scanning calorimetry (DSC) indicated that the Form I polymorph was formed.

Provenance & Evidence