Methane → HCID 20135506, compound

Participants

Reaction Steps

Ethylamine (34 g) is added dropwise, in the course of 5 minutes, to a solution of methyl 2-(pyridin-3-yl)tetrahydrothiopyran-2-carbodithioate 1-oxide (10.7 g) in ethanol (120 cc), kept at between 20° and 25° C. The solution is then stirred for 1 hour 30 minutes at the same temperature and then concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 50° C. The product obtained (12 g) is chromatographed on neutral silica gel (0.040-0.063 mm; 145 g) contained in a column of diameter 4 cm, under a pressure of 40 kPa. The column is eluted with a mixture of ethyl acetate and methanol (90/10 by volume), one 300 cc fraction and thirty-two 120 cc fractions being collected. Fractions 16 to 33 are combined and concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The product obtained (4 g) is dissolved in a boiling mixture of methyl ethyl ketone (9 cc) and diisopropyl ether (2 cc); after cooling, the solution is kept at a temperature of about 0° C. for 2 hours. The resulting crystals are filtered off, washed with methyl ethyl ketone (3 cc) and with diisopropyl ether (0.5 cc) and dried under reduced pressure (20 mm Hg; 2.7 kPa) at a temperature of about 20° C. The product obtained (2.6 g), to which 1.2 g prepared under the same condtions in an earlier operation have been added, is dissolved in boiling methyl ethyl ketone (25 cc); the solution is treated with decolourising charcoal (0.2 g) and filtered hot and the filtrate is cooled and kept at a temperature of about 0° C. for 1 hour 30 minutes. The resulting crystals are filtered off, washed with methyl ethyl ketone (6 cc) and dried under reduced pressure (1 mm Hg; 0.13 kPa) at 60° C. This gives the A form of N-ethyl-2-(pyridin-3-yl)tetrahydrothiopyran-2-carbothioamide 1-oxide (3 g) melting initially at about 169° C. and then, after resolidification, at 183° C. [Rf=0.32; chromatography on a thin layer of silica gel; solvent: ethyl acetate/methanol (80/20 by volume)].

Provenance & Evidence