Organoselenium chemistry. Synthesis of selenetan-3-ol, 1-bromo-3-selenocyanatopropan-2-ol and 2-benzylseleno-substituted fumaricand succinic acids

Abstract

Approaches to the synthesis of diselenols have led to isolation of several new organoselenium compounds. Removal of mercury, as HgS, from [1,3-diselenylpropan-2-olato(2–)-Se,Sel]-mercury(II) results in decomposition of the organoselenium fragment to selenetan-3-ol, 1,3-Dibromopropan-2-ol reacts with KSeCN to form 1-bromo-3-selenocyanatopropan-2-ol; the selenoethers 2-(benzyl- se1eno)fumaric acid [(Z)-PhCH₂SeC(CO₂H)=CHCO₂H] and 2-(benzylseleno)succinic acid [PhCH₂SeCH(CO₂H)CH₂CO₂H] are formed by base-catalysed reaction of phenylmethaneselenol with acetylenedicarboxylic acid and maleic acid, respectively. The conformations adopted by PhCH₂XCH(CO₂H)CH₂CO₂H (X = S, Se) in acetone have been determined by ¹H n.m.r. spectroscopy.