ethyl 2-cyclohexylidene-2-fluoroacetate

diethyl 2-methylsulfanylpropanedioate

(Z)-ethoxy-(3-methyl-2-methylsulfanyl-4-oxo-1,3-thiazol-3-ium-5-ylidene)methanolate

ethyl 4-oxo-2-sulfanylidene-1,3-thiazolidine-5-carboxylate

ethyl 3-methyl-4-oxo-2-sulfanylidene-1,3-thiazolidine-5-carboxylate