Bogdan Jurca

Carbonic anhydrase inhibitors - Part 49: Synthesis of substituted ureido and thioureido derivatives of aromatic/heterocyclic sulfonamides with increased affinities for isozyme I

Reaction of nine aromatic/heterocyclic sulfonamides containing a free amino group with aryl isocyanates/isothiocyanates or allyl isothiocyanate afforded the corresponding urea/thiourea derivatives, which were characterized by standard physico-chemical procedures and assayed as inhibitors of three isozymes of carbonic anhydrase (CA), i.e. hCA I, hCA II and bCA IV (h = human, b = bovine isozyme). Another series of compounds, 1,5-disubstituted-2-thiobiuret derivatives, were prepared by reaction of 3,4-dichlorophenyl isocyanate with thioureido-containing aromatic/heterocyclic sulfonamides. Good inhibition of all these three CA isozymes was observed with the new compounds, but an exciting finding was that the ureas/thioureas and especially the above-mentioned thiobiurets reported here have an increased affinity to the slow isozyme hCA I, generally less susceptible to inhibition by sulfonamides, as compared to the rapid isozymes hCA II and bCA IV. Some of the new compounds might constitute good lead molecules for developing more selective CA I inhibitors.

Study of the Luminescent and Magnetic Properties of a Series of Heterodinuclear [ZnIILnIII] Complexes

Herein, we report the synthesis, structural investigation, and magnetic and photophysical properties of a series of 13 [Zn(II)Ln(III)] heterodinuclear complexes, which have been obtained employing a Schiff-base compartmental ligand derived from o-vanillin [H(2)valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol)]. The complexes have been synthesized starting from the [Zn(valpn)(H(2)O)] mononuclear compound and the corresponding lanthanide nitrates. The crystallographic investigation indicated two structural types: the first one, [Zn(H(2)O)(valpn)Ln(III)(O(2)NO)(3)], contains 10-coordinated Ln(III) ions, while in the second one, [Zn(ONO(2))(valpn)Ln(III)(H(2)O)(O(2)NO)(2)]·2H(2)O, the rare earth ions are nine-coordinated. The Zn(II) ions always display a square-pyramidal geometry. The first structural type encompasses the larger Ln ions (4f(0)-4f(9)), while the second is found for the smaller ions (4f(8)-4f(11)). The dysprosium derivative crystallizes in both forms. Luminescence studies for the heterodinuclear compounds containing Nd(III), Sm(III), Tb(III), Dy(III), and Yb(III) revealed that the [Zn(valpn)(H(2)O)] moiety acts as an antenna. The magnetic properties for the paramagnetic [Zn(II)Ln(III)] complexes have been investigated.

Self-assembly of [CuIITbIII]3+ and [W(CN)8]3− tectons: a case study of a mixture containing two complexes showing slow-relaxation of the magnetization

The reaction of [Cu(valen)] with Tb(NO(3))(3) and (Bu(3)NH)(3)[W(CN)(8)] affords two types of crystals: [{W(CN)(8)}Cu(valen)Tb(OH(2))(5)]·2H(2)O (1, a discrete trinuclear complex) and [{W(CN)(8)}Cu(valen)Tb(OH(2))(4)]·CH(3)CN·H(2)O (2, an infinite zig-zag chain), both compounds showing slow relaxation of the magnetization (H(2)valen is the Schiff base resulting from the reaction of o-vanillin with 1,2-ethanediamine).

Biopolymer starch mediated synthetic route of multi-spheres and donut ZnO structures

A starch-assisted synthetic methodology of multispheres ZnO-starch biocomposites was developed. An additional thermal processing of the ZnO-starch composites induces the formation of ZnO with donut-like morphology. The synthesis of single-phase zinc oxide with a spherical morphology is conditioned by the presence of starch, which acts as template, stabilizing/capping agent. The synthesized structures present significant photocatalytic activities; a total phenol mineralization is attained with the donut-like ZnO photocatalyst under visible light irradiation, due to a cumulative effect of the its relatively large specific surface area, high crystallinity and favorable combination of defects for band narrowing, which together permit an enhanced utilization rate of the light.

A new cyanido-bridged [{C L}2(μ-NC)2MoIV(CN)6] pentanuclear complex (L2−=bicompartmental macrocyclic ligand): synthesis, spectral, and structural characterization

An unprecedented pentanuclear hetero-bimetallic complex has been obtained by a self-assembling process between {Cu2L}2+ binuclear cationic units and [Mo(CN)8]4− anions. The compound with the formula [{C L}2(µ-NC)2MoIV(CN)6(CH3OH)1.5(H2O)0.5] · [{C L}2(µ-NC)2MoIV(CN)6(CH3OH)2] · 5H2O · 7.5CH3OH (1) (H2L = binucleating Schiff-base obtained by condensation of 2,6-diformyl-4-methylphenol with 1,3-propylenediamine), 1, crystallizes in P 1 triclinic space group and consists of two pentanuclear species, [{C L}2(µ-NC)2MoIV(CN)6(CH3OH)1.5(H2O)0.5] (A), [{C L}2(µ-NC)2MoIV(CN)6(CH3OH)2] (B) and solvent. In each unit, two {Cu2L}2+ cations are bridged by one octacyanidomolybdate, via two cis-cyanido groups. Non-covalent channel motifs are developed through a complex network of supramolecular interactions (hydrogen bonds, π–π stacking interaction) involving A and B units and lattice solvent molecules.

Thermal and Kinetic Studies on the Stability of Some Ureido-Sulfonamide Derivatives

AbstractThe kinetic and thermal behaviour of the following compounds: R-HN-CO-NH-(CH2)n-C6H4-SO2NH2 where R=3,4-dichlorophenyl, phenyl, cyclohexyl; n=0, 1, 2 were studied by TG and DTA techniques.The compounds decompose in many steps; the last one corresponding to the burning of H2N–S–C6H4–C6H4–S–NH2 occurs with comparable reaction rates.