Publications by authors named "Vladimir Divjakovic"

Naturally occurring styryl lactone, crassalactone D (1), unnatural 4-epi-crassalactone D (2), and the corresponding 7-epimers (3 and 4) have been synthesized starting from d-glucose. The key step of the synthesis is a new one-pot sequence that commenced with a Z-selective Wittig olefination of suitably functionalized sugar lactols with a stabilized ylide, (methoxycarbonylmethylene)-triphenylphosphorane, in dry methanol, to afford 1 or 3, in the mixtures with the corresponding 4-epimers (2 or 4, respectively). A number of 6-O-cinnamoyl derivatives of styryl lactones 1-4 have been prepared, bearing electron donating or electron withdrawing functionalities in the C-4 position of cinnamic acid residue.

View Article and Find Full Text PDF

A series of new antitumour lactones containing the [3.3.0] bicyclic furano-lactone core and the halogen or azido group at the C-7 position have been designed, synthesized, and evaluated for their in vitro antitumour activity against a panel of human tumour cell lines.

View Article and Find Full Text PDF

A new synthesis of goniobutenolides A (1) and B (2) and the corresponding 7-epimers has been achieved starting from diacetone d-glucose. The key step of the synthesis is a new one-pot sequence that commenced with Z-selective Wittig (or Horner-Wadsworth-Emmons) olefination, followed by successive γ-lactonisation and β-elimination. The above-mentioned unsaturated lactones were then converted to the corresponding 5-halogenated crassalactone D derivatives by using the appropriate haloetherification protocol.

View Article and Find Full Text PDF

A series of styryl lactones containing the cinnamic acid ester groups such as (+)-crassalactones B (3a) and C (4a), 5,7-di-O-cinamoyl derivative 6, the corresponding 7-epimers and 7-deoxy derivatives have been synthesized, characterized and evaluated for their in vitro antitumour activity against a panel of several human tumour cell lines. Twelve new analogues such as 5-O- or 7-O-(4-methoxycinnamoyl), 5-O- or 7-O-(4-nitrocinnamoyl) and 5-O- or 7-O-(4-fluorocinnamoyl) esters of (+)-goniofufurone (3b-d), 7-epi-(+)-goniofufurone (epi-3b-d), as well as 7-deoxy derivatives 5b-d have been prepared to correlate all compounds in a SAR study. Some of the analogues displayed powerful antiproliferative effects on selected human tumour cell lines, but none of them demonstrated cytotoxicity towards the normal foetal lung fibroblasts (MRC-5).

View Article and Find Full Text PDF

Synthesis of conformationally restricted (+)-goniofufurone (1) and 7-epi-(+)-goniofufurone (2) analogues, with embedded O-isopropylidene, O-methylidene or cyclic carbonate functions is disclosed starting from d-glucose. A number of potential bioisosteres of 1 and 2 bearing both 5,7-O-methylidene and 4-substituted cinnamoyloxy functions at the C-7 position have also been synthesized. In vitro cytotoxicity of target molecules against a number of human tumour cell lines were recorded and compared with those observed for the parent molecules 1 and 2.

View Article and Find Full Text PDF

Five new compounds belonging to the phosphoric triamide family have been synthesized: two of them with the formula XC(O)NHP(O)Y [X = CF3 (1) and CClF2 (2), Y = NHCH2C(CH3)2CH2NH] involving a 1,3-diazaphosphorinane ring part, and three 2,6-Cl2C6H3C(O)NHP(O)Z2 phosphoric triamides [Z = NHC(CH3)3 (3), N(CH3)(C6H11) (4) and N(CH3)(CH2C6H5) (5)]. The characterization was performed by (31)P{(1)H}, (1)H, (13)C NMR, IR spectroscopy besides (19)F NMR for fluorine containing compounds (1) and (2), and X-ray single-crystal structure analysis for (1), (3), (4) and (5). In each molecule the P atom has a distorted tetrahedral environment.

View Article and Find Full Text PDF

The title ferrocene-containing Mannich base, [Fe(C(5)H(5))(C(16)H(16)NO(2))], crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. Mol-ecules A and B have similar conformations. The dihedral angles between the best planes of the benzene and substituted cyclo-penta-dienyl rings are 88.

View Article and Find Full Text PDF

Recrystallization of the title compound, [Fe(C(5)H(5))(C(14)H(13)N(2)O(3))], from a mixture of n-hexane and dichloromethane gave the new polymorph, denoted (I), which crystallizes in the same space group (P1) as the previously reported structure, denoted (II). The Fe-C distances in (I) range from 2.015 (3) to 2.

View Article and Find Full Text PDF

Indium promoted allylation of carbonyl compounds with 4-(bromomethyl)-1,3-dioxol-2-one diastereoselectively affords anti-α,β-dihydroxyketones, protected as enol carbonates. These initial products can be deprotected to free dihydroxyketones or transformed under mild conditions into the corresponding cyclic carbonates, which constitutes a useful approach to hydroxyacetone aldols.

View Article and Find Full Text PDF

In the new tin(IV) and copper(II) complexes, cis-dichlorido-trans-dimethyl-cis-bis(N,N',N''-tricyclohexylphosphoric triamide-κO)tin(IV), [Sn(CH(3))(2)Cl(2)(C(18)H(36)N(3)OP)(2)], (I), and trans-diaquabis(N,N',N''-tricyclohexylphosphoric triamide-κO)copper(II) dinitrate-N,N',N''-tricyclohexylphosphoric triamide (1/2), [Cu(C(18)H(36)N(3)OP)(2)(H(2)O)(2)](NO(3))(2)·2C(18)H(36)N(3)OP, (II), the N,N',N''-tricyclohexylphosphoric triamide (PTA) ligands exist as hydrogen-bonded dimers via P=O···H-N interactions around the metal center. The asymmetric unit in (I) consists of one complete complex molecule located on a general position. The Sn(IV) coordination geometry is octahedral with two cis hydrogen-bonded PTA ligands, two cis chloride ligands and two trans methyl groups.

View Article and Find Full Text PDF

In the title compound, C(16)H(16)Cl(4)N(3)O(2)P, the phosphoryl and carbonyl groups are anti to each other. The dihedral angle between the benzene rings is 33.59 (16)°.

View Article and Find Full Text PDF

The reaction of aqueous solutions of amino-guanidine hydrogennitrate and acetyl-acetone produces the title pyrazole salt, C(7)H(18)N(8) (2+)·2NO(3) (-). The crystal structure is stabilized by a complex N-H⋯O hydrogen-bonding network. The difference in the engagement of the two nitrate anions in hydrogen bonding is reflected in the variation of the corresponding N-O bond lengths.

View Article and Find Full Text PDF

The P atom in the title compound, C(19)H(29)N(4)O(4)P, exhibits a tetra-hedral coordination and the phosphoryl and carbonyl groups are anti to each other. Adjacent mol-ecules are linked by N-H⋯O hydrogen bonds to form a layer motif.

View Article and Find Full Text PDF

The title compound, C(19)H(18)NO(3)P, was prepared by the reaction of diphenyl phospho-rochloridate and benzyl-amine. In the crystal structure, mol-ecules are linked via N-H⋯O=P hydrogen bonds into extended chains parallel to the c axis.

View Article and Find Full Text PDF

A copper(II) complex with the pyridoxal-aminoguanidine (PL-AG) Schiff base adduct, as an organic compound of the very potent biological activity and promising pharmacological importance in the treatment of diabetic complications, has been prepared and characterized. The X-ray structural analysis of the [CuCl2(PL-AG)] complex showed that it has a distorted pseudo-square-pyramidal (4+1) structure with the tridentate ONN Schiff base in the equatorial plane, with the Cu-O(1), Cu-N(1) and Cu-N(3) bond lengths of 1.917(2)A, 1.

View Article and Find Full Text PDF