Synthesis and Structural Study of Novel Selenation Derivatives of N, N-Dialkylcyanamides

The reaction of 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide {[PhP(Se)(m-Se)] 2, Woollins' reagent, WR} with N, N-dialkylcyanamides 1-3 in refluxing toluene solution led to the corresponding [2+ 3] cycloaddition products 4-dialkylamino2,5- diphenyl-1,3,2,5-selenazadiphosphole 2,5-diselenides 4-6 in good yields, the latter were further treated with water resulting in the corresponding hydrolysis derivatives dialkyl-selenoureas 7-9, and phosphinodiselenoates 10 and 11. Selenourea 7 could be transferred into 1,3-selenazol-2-amines 12-15 in excellent yields by further cyclization with four different alpha-haloketones. All new compounds have been characterized by IR spectroscopy, multi-NMR (H-1, C-13, P-31, Se-77) spectroscopy and accurate mass measurement. The single crystal X-ray structural features of nine new compounds are also discussed.