Isopropanol → HCID 20190405, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of N-nicotinoyl-4-hydroxyproline (34 g) in a mixture of 2-chloroacrylonitrile (115 cc) and of acetic anhydride (150 cc) is heated at a temperature of about 90° C. for 3 hours and 40 minutes. The solution obtained is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at a temperature of about 70° C. The residue obtained is suspended in a 5 N aqueous solution of sodium hydroxide (500 cc) and the resulting suspension is extracted 4 times with ethyl acetate (1,250 cc in total). The organic extracts are combined, washed 4 times with distilled water (1,000 cc in total), dried over anhydrous magnesium sulphate, treated with decolourising charcoal (0.5 g), filtered and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at a temperature of about 60° C. A crude product (13 g) is thus obtained, which is dissolved in boiling isopropanol (130 cc). The solution obtained is filtered hot and the filtrate is cooled at a temperature of about 20° C. for 2 hours. The crystals which have appeared are separated off by filtration, washed twice with isopropanol (50 cc in total) and 3 times with diethyl ether (150 cc in total), and then dried under reduced pressure (20 mm Hg; 2.7 kPa) at a temperature of about 20° C. in the presence of potassium hydroxide pellets. 2-Hydroxy-5-(3-pyridyl)-2,3-dihydro-1H-pyrrolizine-7-carbonitrile (5.6 g) is thus obtained in the form of beige crystals melting at 190° C.

Provenance & Evidence