Dienes. Control of 1.2and 1.4-Addition Pathways and the Synthesis of Aza-and Oxa-bicyclic Systems

The synthesis and pharmacological activity of a series of 2-substituted derivatives of the selective alpha 2-adrenoreceptor antagonist idazoxan (RX 781094) is described. Substitution in this position by alkyl, alkenyl, cycloalkenyl, and alkoxy groups in many cases gives compounds whose potencies and selectivities are significantly greater than those of the parent compound.

A practical synthesis of 2,3‐dihydro‐2‐benzofurancarboxylic acid is reported in five steps and approximately 40% overall yield. The methodology offers a useful new route to 2‐substituted‐2,3‐dihydrobenzofurans.

In a synthesis capable of extension, 2-phenyl-1,3,2-dioxaphospholan reacts at room temperature with phenyl azide followed by diols, o-dihydroxyarenes, or o-hydroxythiophenol to give phosphoranes (6S-100~0) including the first isolated phosphoranes containing 7-and %membered alicyclic rings, i.e. 2,2-ethylenedioxy-2phenyl-l,3,2-dioxaphosph(v)epan and 2,2-ethylenedioxy-Z-phenyl-l,3,2-dioxaphosph(v)ocan.

Funktionelle Azide reagieren mit Organo‐phosphodIII)‐Verbindungen entsprechend dem Formelschema zu Phosphoranen.