Diethyl acetylenedicarboxylate → ethyl 2-morpholino-7H-1,3,4-thiadiazolo-[3,2-a]-pyrimidin-7-one-5-carboxylate

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Reaction Conditions

Reaction Steps

3.5 g of the 2-amino-5-morpholino-1,3,4-thiadiazole obtained in Example 1 were mixed with 40 ml of absolute ethanol and then 3.2 g of diethyl acetylendicarboxylate was added. The reaction mixture was heated on a water bath to about 60° C. until a clear solution was formed. This was stored overnight at room temperature and then evaporated in vacuo to dryness. The residue was triturated with a small amount of cold ethanol, filtered off, washed with ether and finally dried. Thus 3.8 g, corresponding to 65.2% of the theoretical yield, of ethyl 2-morpholino-7H-1,3,4-thiadiazolo-[3,2-a]-pyrimidin-7-one-5-carboxylate, melting at 151° to 153° C., was obtained.

Provenance & Evidence