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Fluconazole cocrystals were prepared with the intention to modify physicochemical properties of the antifungal agent. The well-known COOH···Naromheterosynthon was considered the key element in the cocrystals design strategy. Cocrystals of fluconazole with maleic, fumaric, and glutaric acid were identified in solution evaporation experiments with pharmaceutically acceptable dicarboxylic acids and their crystal structures are presented. Solid-state NMR as an alternative technique for providing structural information of cocrystals offered additional insights into hydrogen bonding and other inter- as well as intramolecular interactions.

Reaction of CuX2 (X = Cl, Br) with pyridine alcohol ligands [2-(hydroxymethyl)pyridine = Hhmp, 2-(hydroxyethyl)pyridine = Hhep and 2-(hydroxypropyl)pyridine = Hhpp] affords a series of new CuII alkoxide complexes with a similar Cu2O2 structural motif: a dinuclear complex, [Cu2(hpp)2Br2] (1), two tetranuclear compounds, [Cu4(hpp)4Br4] (2) and [Cu4(hpp)4Cl4] (3), and polynuclear chains, [Cu2(hep)2Cl2]n (4) and [Cu2(Hhmp)2Cl4]n (5). The dinuclear complex 1 represents the basic building unit of the four other materials. In this family of compounds, the pyridine alcohol type ligands (Hhmp, Hhep, or Hhpp) provide the two alkoxido functions that bridge the CuII centers. The tetranuclear analogues exhibit an unusual structure of the defect dicubane-like type with two missing vertices. The one-dimensional polymers 4 and 5 are composed of Cu2O2 dinuclear units interlinked through bridging chlorido ligands to form infinite chains. The analysis of the magnetic susceptibility measurements indicates the presence of strong antiferromagnetic coupling between the S = 1/2 CuII metal ions through the bis(alkoxido) bridge. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

The crystal structures of two monomeric copper(II) carboxylates with 2-aminopyridine have been determined by X-ray diffraction. The hexanoate complex crystallizes as its acetonitrile solvate [Cu(C6H11O2)2(C5H6N2)2· CH3CN] in the triclinic space group P-1 with a= 8.1020(6), b= 13.7106(9), c= 13.7673(9) Å, α = 113.79(1), β = 103.86(1), and γ = 94.38(4). The heptanoate compound shows an unsolvated structure [Cu(C7H13O2)2(C5H6N2)2] and also crystallizes in the triclinic space group P-1 with the following cell parameters: a= 8.4487(9), b= 12.238(1), c= 13.504(2) Å, α = 87.034(9), β = 77.489(9), and γ = 71.41(1)°. Both compounds contain the CuO4N2chromophore, with ligands arranged around the copper center in a cismode. 2-Aminopyridine is coordinated through the endocyclic nitrogen atom. The orthoposition of the amino group, with respect to the pyridine nitrogen atom, allows the formation of both, intra-and intermolecular hydrogen bonds.

Reactions of copper(II) carboxylates with 4-aminopyridine (4-apy) were investigated and their products structurally characterized by single crystal X-ray diffraction. Reaction of copper(II) acetate resulted in two isomers of a monomeric complex of composition Cu(ac)₂(4-apy)₂ with markedly different stabilities: the violet form, 1, unstable in air and the blue, stable form, 2. In both isomers the ligands are arranged around the copper atom in a trans geometry. The 4-apy ligands lie almost in the plane in 1, while they are twisted with respect to each other in 2. Variations were observed also in the coordination of the acetate groups to the copper ion. The energy difference between the two isomers was obtained on the basis of ab initio MO calculations. The result agrees well with the observed relative stabilities in the solid state. Monomeric complexes of the same stoichiometry were obtained also by the reaction of Cu(II) hexanoate and heptanoate with 4-apy. The violet Cu(hex)₂(4-apy)₂, 3, and Cu(hep)₂(4-apy)₂, 4, are isostructural and possess trans geometry of the ligands around the copper centre. Reaction of 4-apy with Cu(II) octanoate lead to formation of a novel, unprecedented basic centrosymmetric tetranuclear compound of composition Cu₄(oct)₆(OH)₂(4-apy)₂, 5. Complex 5 contains bidentate bridging and monoatomic bridging carboxylate groups, triply bridging hydroxyl groups and 4-aminopyridine as a terminal ligand. In all five compounds 4-apy is coordinated through the endocyclic nitrogen atom only.

Cycloadditions of various 1,3-dipoles to (5Z)-1-acyl-5-(cyanomethylidene)-3-methylimidazolidine-2,4-diones 8 or 9, prepared in 3 steps from hydantoin (1) (Schemes 1 and 2), were studied. In all cases, reactions proceeded regio- and stereoselectively. The type of product depended on the 1,3-dipole and/or dipolarophile employed as well as on reaction conditions. Thus, with stable dipoles under neutral conditions, spirohydantoin derivatives 12 – 16 were obtained (Scheme 2), while under basic or acidic conditions, pyrazole- or isoxazole-5-carboxamides 18 and 23 – 26 and carboxylate 27 were formed via aromatization of the newly formed dihydroazole ring, followed by the simultaneous cleavage of the hydantoin ring (Schemes 3 – 5).

A series of copper(ii) carboxylates with 2-aminopyridine was prepared. In all cases typical dinuclear complexes with a paddle-wheel type structure, Cu₂X₄L₂, as well as mononuclear complexes of type CuX₂L₂ were obtained (X=hexanoate, heptanoate, octanoate or nonanoate, L=2-aminopyridine). The structures of monoclinic Cu₂(O₂CC₇H₁₅)₄(C₅H₆N₂)₂, 1, and Cu(O₂CC₇H₁₅)₂(C₅H₆N₂)₂, 2, were determined by X-ray diffraction. VIS-absorption spectroscopic and isothermal calorimetric titrations, were employed to investigate the dimer–monomer equilibrium in acetonitrile solutions. The results were analysed on the basis of the mass-action model to obtain the equilibrium constants of monomer formation (K_M≈10⁴ L mol^-1). The thermodynamic analysis shows that for all studied systems monomer formation is an enthalpy-driven process (ΔH_M^°≈-14 kJ mol^-1). The observed exothermic ΔH_M^° values result most likely from the attractive coordinative interactions between Cu²⁺ ion and 2-aminopyridine.

The crystal structures of the first stable α‐diol from the α‐halogenopyruv­amide series, 3‐chloro‐2,2‐di­hydroxy‐3‐phenyl­propan­amide, C9H10­ClNO3, and three products [3‐(4‐chloro­phenyl)‐2‐cyano‐2,3‐epoxy­propan­amide, C10H7­ClN2O2, 3‐bromo‐2‐cyano‐2‐hydroxy‐3‐p‐tolyl­propan­amide, C11H11Br­N2O2, 3‐bromo‐2‐oxo‐3‐p‐tolyl­propan­amide, C10H10­BrNO2] obtained during the systematic synthesis of α‐halogenopyruv­amides are reported. The crystal structures are dominated by hydrogen bonds involving an amide group. The stability of the geminal diol could be ascribed to hydrogen bonds which involve both hydroxyl groups.

Two compounds have been prepared during the investigation of the reactivity of α-halopyruvamides. The reaction products: 3-(4-chlorophenyl)imidazo[1,2-a]pyridine-2-carboxamide (1) and 7-carbamoyl-5-phenyl-2,3-dihydro[1,3]thiazolo[4,3-b][1,3]thiazol-4-ium chloride (2) were structurally characterized by x-ray crystallography. Compound 1 crystallizes in the orthorhombic space group Pca21with a = 28.813(2), b = 9.369(1), and c = 9.361(1) Å. The structure contains two crystallographically different molecules. Compound 2 crystallizes in the monoclinic space group P21/c with the following cell parameters: a = 8.5895(8), b = 22.499(2), c = 7.4133(6) Å, and β = 110.204(1)°.

The title compounds, tetrakis(μ‐benzoato‐O:O′)­bis(2,6‐di­amino­pyridine)‐1κN,2κN‐dicopper(II)–aceto­nitrile (1/2), [Cu2(C7H5O2)4(C5H7N3)2]·2C2H3N, (I), and bis­(aceto­nitrile)‐1κN,2κN‐tetrakis(μ‐benzoato‐O:O′)­dicopper(II)–aceto­nitrile (1/1.5), [Cu2(C7H5O2)4(C2H3N)2]·1.5C2H3N, (II), crystallize as aceto­nitrile solvates exhibiting different stability. They have similar molecular structures with discrete dimeric units located at crystallographic inversion centres. The copper ions are bridged by four benzoate groups and neutral N‐donor ligands, viz.2,6‐di­amino­pyridine in (I) and aceto­nitrile in (II), are coordinated at apical positions. The diverse stability is probably due to hydrogen‐bond interactions of the solvated aceto­nitrile mol­ecules with neighbouring dimers in compound (I).

The structure of the title compound, Na2[Zn(C6H11O2)4], consists of two‐dimensional polymeric sheets. The Zn2+ions are approximately tetrahedrally coordinated by O atoms from different hexanoate anions. Both Na+ions are six‐coordinated by carboxyl­ate O atoms. One of the hexanoate O atoms is attached to one Zn2+ion and one Na+ion, and the remaining O atom is attached to two Na+ions.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.