Riza Abbasoglu

BROMINATION OF BENZHOMOBARRELENE DERIVATIVES : 10. HIGH TEMPERATURE BROMINATION

Abstract The electrophilic addition of bromine to benzhomobarrelene derivatives 18a and 18b in CCl4 at low temperatures (O °C) followed by repeated chromatography combined with fractional crystallization allowed us to isolate seven (19a–25a) and five products (19b–23b), respectively. Structural determinations of these compounds revealed that the barrelene skeleton was mainly rearranged. Alcohol 24a and ketone 25a are secondary products and arise from 21a and 22a. However, high temperature (77 °C) bromination of compounds 18a and 18b gave only nonrearranged products 19 and 20 whose barrelene skeletons were preserved. It is our conclusion that the low temperature reaction is ionic, where in the high temperature reaction radical intermediates are involved. The mechanism for the formation of the products is discussed and is supported by computational calculations. The structures of 21, 22 and 23 revealed that bromine approachs the double bond from the endo-face of the π-system. The reaction of 18a with m-chloroperbenzoic acid gave only endo-epoxide 40, which in turn supports also the endo-selectivity of the double bond in 18a and 18b.

Synthesis and characterization of a novel (E,E)-dioxime and its mono- and heterotrinuclear complexes containing a 21-membered trioxadithiadiaza macrocycle

The novel (E,E)-dioxime, 5,6:17,18-dibenzo-11,12-(4-nitrobenzo)-2,3-bis(hydroxyimino)-7,16-dithia-10,13-dioxa-1,4-diazacyclooctadecane) (H2L), has been synthesized from reaction of (E,E)-dichloroglyoxime (1) with 2,3:14,15-dibenzo 8,9-(4-nitrobenzo)-4,13-dithia-7,10-dioxa-1,16-diazahegzadecane (2). The mononuclear Co(III) complex (4) of this dioxime was prepared by oxidation of the cobalt (II) complex. The -capped Co(III) complex (5) was synthesized by using a precursor Co(III) complex and boron trifluoride dietherate. The heterotrinuclear complexes (6) and (7) were prepared by reaction of (5) with NiCl2·6H2O and CdCl2·H2O, respectively. In addition, the homotrinuclear Cu(II) complex (8), has also been prepared by the reaction of this dioxime with CuCl2·H2O. The structures of the dioxime and its complexes were identified by using elemental analysis, 1H- and 13C-NMR, IR, and mass spectral data.

A new (E, E)-dioxime and its mono and heterotrinuclear complexes containing an 18-membered dithiatetraazamacrocycle

The novel (E,E)-dioxime, 5,6:ll,12:17,18-tribenzo-2,3-bis(hydroxyimino)-7,16-dithia-9, 14-dioxo-l,4,10,13-tetraazacyclooctadecane (H2L) has been synthesized by reacting (E,E)-dichloroglyoxime (2) with 2,3:8,9:14,15-tribenzo-4,13-di-thia-6,11-dioxa-l,7,10,16-tetraazahexzadecane (3), prepared by the reaction of N,N′-bis(chloroacetyl)-1, 2-phenylene-diamine (1) with 2-aminothiophenol. Mononuclear complexes (4, 5) of this ligand have been synthesized by reacting the vic-dioxime (H2L) with K2PtCl4 and NiCl2 · 6H2O, respectively. Heterotrinuclear complexes (6)and(7) have been prepared by the reaction of (4) and (5) mononuclear complexes with [Cu(MeCN)4]PF6. The structures of the vic-dioxime and its mono and trinuclear complexes were identified by elemental analysis, 1H- and 13C-n.m.r, i.r. and m.s. data.

The synthesis and characterization of a new (E, E)-dioxime, its complex formations of the macrobicyclic group, and conformational analysis of the ligands

In this study, 19-nitro-6,7,15,16,23,24-hexahydro-13H,26H-14,25-propanotribenzo-[b,i,o] [1,4,11,14,7,18] tetraoxadiazacycloicosine (3) was synthesized using 6,7,8,9,10,11,17,18-octahydro-5H-dibenzo[e,n][1,4]dioxa[8,12]diazacyclopentadesine (1) and 4-nitro-1,2-bis(2-iodoethoxy)benzene (2) as the starting compounds. Macrobicyclic amine 4 was synthesized by reaction of an aromatic nitro compound with hydrazine hydrate (100%) and palladium (10%)-activated carbon in n-butanol. N1,N2-di-6,7,15,16,23,24-hexahydro-13H,26H-14,25-propanotribenzo[b,i,o][1,4,11,14,7,18]tetraoxadiazacycloicosin-19-yl-N′1,N′2-dihydroxyethane-diimidamide vic-dioxime (6) was synthesized by reaction of cyanogen-di-N-oxide in CH2Cl2, which was obtained from (E, E)-dichloroglyoxime and an aqueous solution of Na2CO3 (0.1 N) with 4. Mononuclear Ni(II), Co(III), and Cu(II) complexes, 7, 9, and 10, were synthesized by reaction of vic-dioxime with NiCl2·6H2O, CoCl2·6H2O, and CuCl2·2H2O, respectively. -Capped mononuclear Ni(II) complex 8 was synthesized by reaction of boron-trifluoride diethyl etherate with mononuclear nickel(II) complex 7 in acetonitrile. The structures of new compounds were determined by elemental analysis, 1H-NMR, 13C-NMR, IR, mass spectroscopic data, and thermal methods (TG/DTA). The conformational analysis of the ligands was performed using DFT and AM1 methods.

The quantum chemical investigation of molecular complexes formed with bromine molecule of adamantylideneadamantan and its derivatives: electronic and steric effects

Abstract The strain energies and the pyramidalization parameters of adamantylideneadamantan (AD), trans-(1-methyl-2-adamantyliden)-1-methyladamantan (DMAD) and trans-(1-tert-butyl-2-adamantyliden)-1-tert-butyladamantan (DBAD) molecules were calculated by MM2 and AMBER molecular mechanic methods. The strain energy and the pyramidalization degree of the molecule are increased by increasing the volume of R groups at the allylic position of the double bond. The electron structure of the molecules were investigated by PM3 semiempirical method. Molecular mechanic and PM3 methods, the results of which agree with the X-ray results, showed that the double bond of AD molecule has a planar structure. The molecular complexes (1:1 π-complexes) of the molecules formed with Br2 were investigated by PM3 method and it was seen that the stable configuration of them had the axial structure. The electronic and the steric factors affecting the structure and the stability of the molecular complexes were studied. It was found that DMAD⋯Br2 complex is more stable than AD⋯Br2 complex which was in accordance with the experimental results. It was determined that DBAD⋯Br2 complex containing the bulky tert-butyl group has the lowest stabilization energy among the investigated molecular complexes.