EfaroxanEfaroxan is an α2-adrenergic receptor antagonist and antagonist of the imidazoline receptor.SynthesisThe Darzens reaction between 2-fluorobenzaldehyde and Ethyl 2-bromobutyrate gives ethyl 2-ethyl-3-oxirane-2-carboxylate, . A catalytic hydrogenation over Pd/C would give ethyl 2--2-hydroxybutanoate, . Saponification of the ester then gives 2--2-hydroxybutanoic acid, . Treatment with 2 molar equivalents of sodium hydride apparently gives 2-Ethyl-2,3-dihydrobenzofuran-2-carboxylic acid . Treatment of the carboxylic acid with thionyl chloride then gives the acid chloride and subsequent treatment of this with ethylenediamine in the presence of trimethylaluminium completed the synthesis of .