Metabolism of nonesterified and esterified hydroxycinnamic acids in red wines by Brettanomyces bruxellensis.

While Brettanomyces can metabolize nonesterified hydroxycinnamic acids found in grape musts/wines (caffeic, p-coumaric, and ferulic acids), it was not known whether this yeast could utilize the corresponding tartaric acid esters (caftaric, p-coutaric, and fertaric acids, respectively). Red wines from Washington and Oregon were inoculated with B. bruxellensis, while hydroxycinnamic acids were monitored by HPLC. Besides consuming p-coumaric and ferulic acids, strains I1a, B1b, and E1 isolated from Washington wines metabolized 40-50% of caffeic acid, a finding in contrast to strains obtained from California wines. Higher molar recoveries of 4-ethylphenol and 4-ethylguaiacol synthesized from p-coumaric and ferulic acids, respectively, were observed in Washington Cabernet Sauvignon and Syrah but not Merlot. This finding suggested that Brettanomyces either (a) utilized vinylphenols formed during processing of some wines or (b) metabolized other unidentified phenolic precursors. None of the strains of Brettanomyces studied metabolized caftaric or p-coutaric acids present in wines from Washington or Oregon.

Synthesis and characterization of an unsymmetrical cobalt(III) active site analogue of nitrile hydratase.

The design, synthesis, and characterization of an unsymmetrical diamidato-dithiol ligand (H(4) 1, where the hydrogen atoms represent deprotonatable amide and thiol protons) and its cobalt(III) complex, a synthetic analogue of the cobalt-containing nitrile hydratase enzyme family, are reported. The ligand was prepared in 24% yield from an overall eight-step synthetic pathway following a modified protocol established in our laboratory that includes two peptide couples using O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate as the coupling agent. The ligand and all precursors were characterized by NMR spectroscopy and elemental analysis. The cobalt nitrile hydratase synthetic analogue complex [NBu(4)][Co(1)] was prepared on deprotonating ligand H(4) 1 to [1](4-) on addition of 5 equiv of NaH in N,N-dimethylformamide and adding 1 equiv of CoCl(2) at -40 °C under a N(2) atmosphere followed by oxidizing the complex by stirring it overnight open to dry air. The complex [NBu(4)][Co(1)] was isolated after counterion exchange with 1 equiv of NBu(4)Cl followed by crystallization from MeCN/Et(2)O in 71% yield. The structure of the complex was confirmed by X-ray diffraction analysis. Cyclic voltammetry studies on [NBu(4)][Co(1)] in a 0.1 M [NBu(4)][PF(6)]/MeCN solution showed a quasi-reversible reduction potential at -1.1 V (vs. Ag/AgCl), and magnetic susceptibility investigations indicated the complex is paramagnetic in both the solid and the solution states as determined from inverse-Gouy and Evans NMR methods, respectively.

Carbon-yl[tris-(3,5-diphenyl-pyrazol-1-yl-κN)methane]copper(I) hexa-fluorido-phosphate-dichloro-methane-diethyl ether (4/3/1).

In the title compound, [Cu(C(46)H(34)N(6))(CO)]PF(6)·0.75CH(2)Cl(2)·0.25C(4)H(10)O, the Cu(I) atom is coordinated by three N atoms from the tridentate chelating tris-(3,5-diphenyl-pyrazol-1-yl)methane ligand (average Cu-N distance = 2.055 Å) and the C atom from a carbon monoxide ligand in a distorted tetra-hedral coordination geometry. The average N-Cu-N angle between adjacent pyrazole-ring-coordinated N atoms is 88.6°, while the average N-Cu-C angle between the pyrazole-bound N atom and the C atom of carbon monoxide is 126.3°. One of the 3-phenyl rings of the tris-(pyrazol-yl)methane ligand is disordered over two sites each with an occupancy factor of 0.50. The structure also exhibits disorder of the monosolvate that has been modeled with 0.75 CH(2)Cl(2) and 0.25 Et(2)O occupancy.