Ljubo Golic

Antibacterial tests of Bismuth(III)–Quinolone (Ciprofloxacin, cf) compounds against Helicobacter pylori and some other bacteria. Crystal structure of (cfH2)2[Bi2Cl10]·4H2O

The antibacterial tests of two bismuth(III)-ciprofloxacin (cf) compounds against Helicobacter pylori (H. pylori) and some other bacteria were performed. The results have shown that the activity of both compounds is comparable to that of ciprofloxacin hydrochloride. The crystal structure of (cfH2)2[Bi2Cl10].4H2O (cfH2 = doubly protonated molecule of cf) is presented and discussed. The compound was isolated from acidic medium where quinolone is protonated and thus no bonding between quinolone and bismuth was observed. The bismuth(III) ions are coordinated by chloride ions forming dinuclear [Bi2Cl10]4- anions. The charge of this ion is compensated with protonated quinolone molecules (ionic interactions).

Regioselective 1,3-Dipolar Cycloadditions of (1Z)-1-(Arylmethylidene)-5,5-dimethyl-3-oxopyrazolidin-1-ium-2-ide Azomethine Imines to Acetylenic Dipolarophiles

The 5,5-dimethylpyrazolidin-3-one (4), prepared from ethyl 3-methylbut-2-enoate (3) and hydrazine hydrate, was treated with various substituted benzaldehydes 5a – i to give the corresponding (1Z)-1-(arylmethylidene)-5,5-dimethyl-3-oxopyrazolidin-1-ium-2-ide azomethine imines 6a – i. The 1,3-dipolar cycloaddition reactions of azomethine imines 6a – h with dimethyl acetylenedicarboxylate (=dimethyl but-2-ynedioate; 7) afforded the corresponding dimethyl pyrazolo[1,2-a]pyrazoledicarboxylates 8a – h, while by cycloaddition of 6 with methyl propiolate (=methyl prop-2-ynoate; 9), regioisomeric methyl pyrazolo[1,2-a]pyrazolemonocarboxylates 10 and 11 were obtained. The regioselectivity of cycloadditions of azomethine imines 6a – i with methyl propiolate (9) was influenced by the substituents on the aryl residue. Thus, azomethine imines 6a – e derived from benzaldehydes 5a – e with a single substituent or without a substituent at the ortho-positions in the aryl residue, led to mixtures of regioisomers 10a – e and 11a – e. Azomethine imines 6f – i derived from 2,6-disubstituted benzaldehydes 5f – i gave single regioisomers 10f – i.

A Simple Stereoselective Synthesis of Aplysinopsin Analogs

Simple and stereoselective syntheses of aplysinopsins and their analogs from either methyl 2-[(2,2-disubstituted ethenyl)amino]-3-(dimethylamino)prop-2-enoates 11 or 5-[(dimethylamino)methylidene]imidazolidine-2,4-diones 20 are described. The structures of products are established by 1H- and 13C-NMR, and NOESY spectroscopy, and X-ray crystal-structure analysis.

In(III), Tl(III) and V(IV) tris-chelates of the heterocyclic dithiolene and diselenolene ligands 1,3-dithiole-2-thione-4,5-dithiolate (dmit), 1,2-dithiole-3-thione-4,5-dithiolate (dmt) and 1,3-diselenole-2-selone-4,5-diselenolate (dsis). Crystal and molecular structure of (Bu4N)2 [V(dmt)3]

Abstract Synthesis and characterization of the first trischelates of the dichalcogenolene ligands 1,3-dithiole-2-thione-4,5-dithiolate (dmit), 1,2-dithiole-3-thione-4,5-dithiolate (dmt)and 1,3-diselenole-2-selone-4,5-diselenolate (dsis) with the central ions In(III), Tl(III) and V(IV) are reported. On (Bu4N)2[V(dmt)3] the first X-ray structure of a dithiolene tris-chelate containing unsymmetric ligand was carried out: the compound crystallizes monoclinic, space group P21/c, with four molecules in the unit cell; a = 16.264(3), b = 17.319(4), c = 21.554(4) A, β = 103.03(2)°. The ligand dmt causes a very low symmetry of the VS6 moiety in [V(dmt)3]2− having pseudo-meridional arrangement of the three ligands. The EPR parameters of the compounds (Bu4N)2[V(dmit)3] and (Bu4N)2[V(dmt)3] measured in liquid and frozen acetonic solution are compared with those of the tris(maleonitriledithiolato)vanadate(IV) anion supporting a geometry of the anion being between octahedral and trigonal prismatic.

A simple synthesis of aplysinopsin analogues by dimethylamine substitution in N,N-(dimethylamino)methylidene derivatives of five-membered heterocycles

Abstract Some new aplysinopsin analogues were prepared by a simple coupling of N , N -(dimethylamino)methylidene substituted hydantoin, thiohydantoin, and thiazolone derivatives, with indole derivatives. Configuration around the exocyclic CC double bond was determined on the basis of long-range heteronuclear coupling constants using 2D HMBC correlation technique.

New complexes of lanthanide chlorides.: Reversible isomerization in octahedral [LaCl3(HMPA)3] and the crystal structure of fac-[SmCl3(HMPA)3]

Abstract Complexes of [LnCl3L] (Ln=La, Nd, Sm, Eu, and L=diethylene glycol dimethyl ether, diglyme; Ln=La, Pr, and L=dimethoxyethane, DME) were prepared from the lanthanide oxides and hydrogen chloride, which was formed in situ from chlorotrimethylsilane and water. When hexamethylphosphoramide (HMPA) was added to the suspension of the prepared DME and diglyme complexes in toluene, fac-[LnCl3(HMPA)3] (Ln=La, Pr, Nd, Sm, Eu, Gd) complexes, isomorphous according to the unit cell determination, were formed. The crystal structure of [SmCl3(HMPA)3] was determined. Each samarium atom is octahedrally coordinated by three chlorine atoms and three HMPA molecules, which are distributed in a facial mode. The exchange of coordinated and free HMPA, as well as the reversible fac–mer isomerization of [LaCl3(HMPA)3], was observed by variable temperature 1H NMR spectroscopy. The associative mechanism of the exchange and isomerization was proposed.

1,3-dipolar cycloaddition of 2-diazopropane to 2-methyl-6-phenylpyridazin-3(2H)-one. The formation of pyrazolo/3,4-D/pyridazine derivatives

Abstract In a regiospecific 1,3-dipolar cycloaddition of 2- diazopropane to 2-itiethyl-6-phenylpyridazin-3(2H)- one the primary cycloadduct and rearranged NH,NH- dihydro cycloadduct were isolated. They were transformed, dependent on the reaction conditions into 1,2-di- azepine derivative, 4-isopropyl substituted pyridazine derivative, diazabicyclo/4.l.0/heptenone derivative and pyrazolo/3,4-d/pyridazine derivative. 1,5- Sigmatropic rearrangements were observed, when was heated in PPA or concentrated sulphuric acid to give pyrazolo/3,4-d/pyridazine derivatives 0 and 1 , and a pyrazole derivative 3 .

Octanuclear oxomolybdenum(V) clusters with pyridine or alkyl-substituted pyridines: crystal structures of [Mo8O16(OCH3)8L4] (L=3-methylpyridine, 3,5-lutidine)

Abstract Simple synthetic routes for the preparation of octanuclear oxomolybdenum(V) clusters with stoichiometry [Mo8O16(OCH3)8L4] (L=4-methylpyridine (4-MePy) (a), 4-ethylpyridine (4-EtPy) (b), 4-tert-butylpyridine (4-ButPy) (c), pyridine (Py) (d), 3-methylpyridine (3-MePy) (e), 3,5-lutidine (3,5-Lut) (f)) are described. Crystal structures of e and f were investigated by X-ray diffraction. The puckered ring structure made up of eight molybdenum atoms linked together by pairs of methoxy groups and pairs of oxo groups was recognized in both. The solubility of the compounds in pyridines was employed for the substitution of coordinated pyridine for a different pyridine. The octanuclear clusters have been found to react in pyridines at elevated temperatures to oxomolybdenum(V,VI) clusters with the formula [Mo10O26L8].

Synthesis and structure of a new cobalt-containing aluminophosphate

Abstract We report on the synthesis and single-crystal structure of a novel cobalt-substituted aluminophosphate. Crystal data: monoclinic, space group P2 1 c (no. 14), a = 8.593(1), b = 15.540(1), c = 7.736(1)A, β = 110.65(1)°, V = 966.7(4)A3, Z = 4, R = 0.037, and Rw = 0.029 for 2280 contributing reflections and 182 variables. Refined framework-atom bond distances and angles exhibited regular tetrahedral coordination of Al and P [dave(AlO) = 1.74(1)A, dave(PO) = 1.54(2)A] and distorted Co-centered octahedra. The Co substituted every second aluminum in the ordered AlP distribution and was coordinated to five framework oxygen atoms and to one nitrogen atom from a template ethylenediamine molecule located in an eight-member ring opening. Structure collapsed in the absence of template.

Mixed-ligand complexes of technetium IX. Oxidative ligand exchange reactions on tetraphenylarsonium-bis(dithiooxalato)nitridotechnetate(V), (Ph4As)2[TcN(dto)2]. X-ray crystal structure of a further modification of (Ph4As)2[TcN(dto)2]

Abstract (Ph 4 As) 2 [TcN(dto) 2 ] can be prepared starting from TcNCl 4 − or TcNCl 2 (Ph 3 P) 2 . The compound crystallizes in at least two modifications: as well as a triclinic form (S. F. Colmanet and M. F. Mackay, Inorg. Chim. Acta, 147 (1988) 173) a monoclinic one has been found (space group C 2/ c , Z = 4, a = 19.424(3), b = 11.254(2), c = 24.958(3) A, β = 107.68(1)°; R = 0.048). Distances and angles in the complex anions in both modifications are almost identical within experimental error. Oxidation of [TcN(dto) 2 ] 2− by Cl 2 produces the Tc(VI) complex TcNCl 4 − exclusively, whereas during the Br 2 oxidation technetium(VI) intermediates are generated containing mixed Br/dto coordination spheres which can be monitored easily by EPR spectroscopy.