Synthesis of 2,12-Dithia[3](2,6)pyridino[3](1,4)cycl[3.2.2]azinophane and It's Barrier to Methylene Twist

Abstract

t -A synthesis of the title compound (11) is completed starting from indolizine (3).Key intermediate, bis(mercaptomethyl)cyc1[3.2.2]azine (9) has been synthesized by reduction of bis(acetylthiomethyl)cycl[3,2.2]a7ine (8) with LiAIH,.2,12-Dithia[3](2,6)pyridino[3](1,4)cyc1[3.2.2]azinophanes (1 1 a, b) have been synthesized by the reaction of 9 with 2,6-bis(bromomethy1)pyridine (10) in the presence of Cs2C0, by the high dilution method.In the 'H-nmr specbum of 1 la,b, these exist in the syn conformation i' n their 'H-nmr spectra With regard to 2.12-dithia[3](2,6)pyridino[3](1,4)cycI[3.2.2]~ ( l l a ) , the coalescence temperature for the methylene twist yields an activation barrier, A G: of 79.5 kJ mol-' for variable temperature (VT) nmr method Cyclophanes have attracted much attention because of their unusual geometry and interesting proton nuclear magnetic resonance ('H-nmr) spectra.'Recently syntheses of [2.2]cyclophanes containing heteroaromatic nuclei have been reported in the literature.%ongsome of the common heteroaromatic nuclei which have been incorporated into the [2.2]cyclophane macrocycle are furan, thiophene, pyrrole, and pyridine.'However, except for our synthesis of [2.2.2.2](1,4)cyc1[3.2.2]azine derivative,' the literature was devoid of [2.2]cyclophane containing cyc1[3.2.2]azine nucleus4 which was characterized as a nitrogen-bridged,