OLIGOCYCLIC DERIVATIVES FROM THE PARTIAL BROMINATION OF 2-METHYL-5-PHENYL-1,2,4,3-TRIAZAPHOSPHOLE

Abstract

Abstract With less than one mol Br2 per mol of the 2-methyl-5-phenyl-1,2,4,3-triazaphosphole (1) an equilibrium mixture forms, which contains besides 1 and its dimeric dibromide 3 at least three more components (4, 5, 6), which are intermediate between 1 and 3. In 4, 5 and 6 two, three and four triazaphosphole rings are connected to each other by PN bonds with the phosphorus atoms being in part tervalent, in part pentavalent. Secondary amines convert compounds 4 and 5 to the amino derivatives 11 and 12 of the same biand tricyclic structure. Of the bicyclic dimethylamino derivative 11b a number of reactions are reported which all selectively involve the tervalent phosphorus only: Oxidation by bromine, elemental sulfur, phenyl azide and ethyl diazoacetate, insertion of CS2, RNCS and RNCO into the exocyclic PN bond and formation of chelate complexes with PdCl2 and PtCl2. The same is shown by the reaction of the tricyclic piperidyl derivative 12c with elemental sulfur.