Ethyl 2-bromomethyl-5-(1,2,3-thiadiazol-4-yl)furan-3-carboxylate in reactions with O-, S-, N-, and P-nucleophiles

Abstract

Reaction of ethyl 2-bromomethyl-5-(1,2,3-thiadiazol-4-yl)furan-3-carboxylate with nucleophiles of different nature was studied. It is shown that substitution of bromine with acetoxy group takes place under the action of sodium acetate in the acetic acid. Stronger bases, like phenolates, cause considerable decomposition of the labile furylthiadiazole fragment Decomposition can be avoided only when this reaction is carried out in the presence of a phase transfer catalyst under the conditions of the ion pair extraction,. In the reaction with sodium N,N-diethyl dithiocarbaminate the corresponding thioester is formed. Butanethiol and thiophenol are alkylated as potassium thiolates. In the last case S-alkylation proceeds exclusively. Reaction with excess 2-aminoethanol permits to prepare secondary amine, and the reactions with pyrrolidine, piperidine, and morpholine give the corresponding tertiary amines. Phosphorylation with triethyl phosphite under the conditions of Arbuzov reaction leads to the corresponding diethyl phosphonate. In all these transformations furylthiadiazole fragment is retained.