Synthesis and Bioactivity of Some New 3‐Alkyl‐2,4‐diisopropyl‐1,2,4,5‐tetrahydro‐benzo[e][1,3,2]‐diazaphosphepine 3‐sulfides/selenides

• Published in: E-journal of chemistry 2008, Vol.5 (3), p.479-486
• Main Authors: Mohan, Ch, Raju, C. Naga, Rao, A. Janardhan
• Format: Article
• Language: English
• ISSN: 2090-9063; 0973-4945; 2090-9071; 2090-9810
• DOI: 10.1155/2008/594036

Preparation of a series of novel seven membered heterocyclic compounds, 3‐alkyl‐2,4‐diisopropyl‐1,2,4,5‐tetrahydro‐benzo[e][1,3,2] diazaphosphepine 3‐sulfides / selenides ( 8a-l ) was accomplished in four steps. The synthetic route involves α,α ′ ‐dibromo‐ o ‐xylene ( 1 ) with two moles of isopropylamine ( 2 ) in the presence of triethylamine (TEA) in dry tetrahydrofuran (THF) at low temperature to form the compound 3 . This on treatment with phosphorus tribromide ( 4 ) in the presence of TEA in dry THF to form the corresponding phosphorobromodite ( 5 ). This on subsequent reaction with different Grignard reagents ( 6 ) in dry THF under N 2 atmosphere formed the compounds 7 . They are converted to the corresponding sulfides and selenides ( 8a-l ) by reacting them with sulfur and selenium respectively. Their structures were established by elemental analysis, IR, 1 H, 13 C, 31 P NMR and mass spectral data. All the title compounds were screened for their antibacterial activity. Most of the compounds exhibited significant antimicrobial activity.