590424-04-7

14352-65-9

590424-03-6

590424-04-7

The general procedure for the synthesis of tert-butyl 4-((2-(diethylamino)ethyl)carbamoyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate from tert-butyl 2-(hydroxyimino)-3-oxobutanoate (20.0 g; 107 mmol) and the compound (CAS:590424-03-6) (21.4 g; 107 mmol) is as follows. tert-butyl 2-(hydroxyimino)-3-oxobutanoate was added to a 500 mL Parr reactor along with 2.0 g of 5% dry Pd/C catalyst. The compound (CAS:590424-03-6) was dissolved in 220 mL of acetic acid and subsequently added to the Parr reactor. After purging the reactor with nitrogen and hydrogen, the mixture was hydrogenated by heating the reaction for 7 hours at 65°C and 45 psig hydrogen pressure. Upon completion of the reaction, the reaction mixture was cooled to room temperature and the Pd/C catalyst was removed by filtration and the filter cake was washed with acetic acid. The filtrate was neutralized to pH 13 with 50% aqueous sodium hydroxide, followed by the addition of 500 mL of dichloromethane. The pH of the aqueous phase was adjusted to 13 by continued addition of 50% aqueous sodium hydroxide. the mixture was transferred to a partition funnel to separate the organic and aqueous phases. The aqueous phase was extracted with dichloromethane (3 x 350 mL) and the combined organic phases were washed with deionized water (2 x 250 mL). The washed aqueous phase was back-extracted with dichloromethane (250 mL), all organic phases were combined and concentrated under vacuum. The concentrated residue was dissolved in hot acetonitrile, filtered and the solution was cooled and the precipitated solid was separated by filtration to afford 27.7 g (83 mmol; 77% yield) of tert-butyl 4-((2-(diethylamino)ethyl)carbamoyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate.