Lawesson's reagent → 2,3,4,5-Tetrahydro-4-methyl-5-thioxopyrido[3,2-f][1,4]oxazepin-2-propanenitrile

Participants

Reaction Steps

To a solution of 11.0 g (0.04 mole) of 2,3,4,5-tetrahydro-4-methyl-5-oxopyrido[3,2-f][1,4]-oxazepine-2-propanenitrile in 175 ml toluene was added 10.5 g (0.026 mole) of 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide. The reaction mixture was heated to reflux for 2 hr with vigorous mechanical stirring. Another 3.0 g (0.007 mole) of 2,4 bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide was added and heating continued for 1 hr additional. The reaction mixture was allowed to cool and stand overnight at room temperature. Toluene was removed by rotary evaporation (90° C., water aspirator) and the residue taken up in 200 ml chloroform. This was washed with 2×50 ml 2M aqueous potassium hydroxide and concentrated by rotary evaporator (90° C., water aspirator). Crystallization ensued upon cooling. Recrystallization from isopropyl alcohol afforded 1.60 g (13.8%) product, m.p. 155°-56° C.

Provenance & Evidence