p-Toluenesulfonic acid → 2-Ethyl-4-(pyrrolidin-1-yl)-1lambda~6~-naphtho[2,1-e][1,2]thiazine-1,1(2H)-dione

Participants

Reaction Steps

A mixture of 2 gm (7.3 millimols) of 2-ethyl-2H-naphtho[2,1-e]-1,2-thiazine-4(3H)-one-1,1-dioxide, 1.04 gm (14.6 millimols) of pyrrolidine, 200 mgm p-toluenesulfonic acid and 100 mlof benzene was refluxed for 24 hours in a vessel equipped with a water trap. Subsequently, another 1.04 gm (14.6 millimols) of pyrrolidine and 200 mgm of p-toluenesulfonic acid were added, and the reaction mixture wasrefluxed for 24 hours more. After cooling, the reaction mixture was evaporated, and the residue was extracted with ether several times. The combined ether extracts were washed twice with water, dried and evaporated. Recrystallization of the residue from methanol yielded 1.2 g (50% of theory) of the desired enamine, m.p. 115°-117° C.

Provenance & Evidence