engleski

Chemistry of 1, 3-dioxepins. XV.(1) - Syntheses and structure of nitroaryl analogues of antihyperglycaemic N-sulphonyl-1a, 2, 6, 6a-tetrahydro-1H, 4H-[1, 3]ioxepino[5, 6-b]azirines

Regio and stereocontrolled syntheses of novel nitrophenyl analogues of antihyperglycaemic N-sulphonyl-1a, 2, 6, 6a-tetrahydro-1H, 4H-[1, 3]-dioxepino[5, 6-b]azirines: N-nitrobenzenesulphonylcyclohepta[b]azirine 6, N-nitrobenzenesulphonyldioxepinoazirines 7-10, N-nitrobenzoyldioxepinoazirine 11 and N-nitrobenzyldioxepinoazirine 12, starting from cycloheptene (2), trans-6-acetylamino-2-isopropyl-5chloro-1, 3-dioxepane (13) and 5, 6-epoxy-1, 3-dioxepane (14), are described. Their crystallographic data show that: (a) boat-chair (BC) conformation of dioxepinoazirine and cyclohepta[b]azirine moieties dominates ; (b) the substituent on aziridine nitrogen is always in trans and never in cis position in relation to the cycloheptane or dioxepane ring ; (c) the sulphonyl group of sulphonylaziridines 6 and 8-10 adopts only one of the two possible conformations in relation to the aziridine ring, with torsion angles C1-S-N-C7 of congruent to 80 degrees (corresponding angle O1-S-N-LP congruent to 180 degrees, LP = lone pair) named by us conformation BC* (d) orientation of the analogous carbonyl group of 11 and methylene group of 12 is defined by torsion angles C1-C0-N1-C7 of -78.3 (9)degrees and -93.9 (5)degrees respectively ; (e) nitrogen atom in all studied N-sulphonyl-, acyl- and alkyl- aziridines is sp(3) hybridised, in contrast to other sulphonamides where sp(2) hybridisation is predominant ; (f) nitrogen atom in alkylaziridine 12 is more pyramidal in relation to N-sulphonyl and N-acyl derivatives, and according to torsion angles O5-N2-C4-C5, the nitro group in all studied compounds is approximately coplanar to the phenyl ring plane. Obtained data will serve for further investigation of steric and electronic properties of studied compounds aimed at designing more antihyperglycaemically potent analogues.

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