Selenodiazole reactions

The reaction mechanism has not been elucidated. Reducing substances presumably release red elementary selenium [1]. Aromatic o-diamines yield highly fluorescent selenodiazoles with selenium dioxide. 

Cocyclization of 3,4-dicyano-l,2,5-selenodiazole 81 and alkene 234 by reaction with Mg(OBu)2 in BuOH, and subsequent demetalation by trifluoroacetic acid and metalation with MnCl2, led to a porphyrazine containing one 1,2,5-selenodiazole ring Mn complex 235 in 59% yield (Equation 29) <2003AGE462, 2003JOC1665>. 

The reaction of 3,4-dicyano-l,2,5-selenodiazole 81 and alkene 236 with Li or MglO-zr-CsHuL in boiling -penta-nol and subsequent demetalation by either acetic acid (Li) or trifluoroacetic acid (Mg) gave unsymmetrical porphyr-azine with 1,2,5-selenodiazole 89 (Equation 30) <2001MC45>. The structure of product 89 was elucidated by single crystal X-ray diffraction. 

Many reactions of substituted diazepines and their fused derivatives frequently relate to a study of the functionality rather than being dependent on the presence of the azepine ring system, most particularly with reduced derivatives. Reaction of the unsymmetrical semicarbazones (110) <91JOC5203> gives the two selenodiazoles (111) and (112), the ratios of which show a solvent dependency (Equation (8)). 

Application of the Lalezari reaction is highlighted in the synthesis of 1,2,3-selenodiazoles 134, which serve as the precursors of a series of novel 2-aminobenzo[ ]selenophenes (see Section 5.5.4.2) (130L1744). 

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