Structural and Functional Characterization of a Novel Class A Flavin Monooxygenase from .

A gene cluster responsible for the degradation of nicotinic acid (NA) in has recently been identified, and the structures and functions of the resulting enzymes are currently being evaluated to establish pathway intermediates. One of the genes within this cluster encodes a flavin monooxygenase (BnFMO) that is hypothesized to catalyze a hydroxylation reaction. Kinetic analyses of the recombinantly purified BnFMO suggest that this enzyme catalyzes the hydroxylation of 2,6-dihydroxynicotinic acid (2,6-DHNA) or 2,6-dihydroxypyridine (2,6-DHP), which is formed spontaneously by the decarboxylation of 2,6-DHNA.

Synthesis and crystallographic characterization of 6-hydroxy-1,2-dihydropyridin-2-one.

The title compound, CHNO, is a hy-droxy-lated pyridine ring that has been studied for its involvement in microbial degradation of nicotinic acid. Here we describe its synthesis as a formic acid salt, rather than the standard hydro-chloride salt that is commercially available, and its spectroscopic and crystallographic characterization.

Facile formation of β-hydroxyboronate esters by a Cu-catalyzed diboration/Matteson homologation sequence.

The copper-catalyzed diboration of aldehydes was used in conjunction with the Matteson homologation, providing the efficient synthesis of β-hydroxyboronate esters. The oxygen-bound boronate ester was found to play a key role in mediating the homologation reaction, which was compared to the α-hydroxyboronate ester (isolated hydrolysis product). The synthetic utility of the diboration/homologation sequence was demonstrated through the oxidation of one product to provide a 1,2-diol.

A general synthesis of phosphaalkenes at zirconium with liberation of phosphaformamides.

A general, atom-economical method for the synthesis of phosphaalkenes is reported via the net coupling of primary alkyl or aryl phosphines with aryl or alkyl isocyanides at zirconium. The phosphorus-containing ligand can be liberated as the phosphaformamide from zirconium by reaction with an organic electrophile.

Iridium-catalyzed, substrate-directed C-H borylation reactions of benzylic amines.

The iridium-catalyzed arene C-H borylation reaction of benzylic amines has been developed, which inverts the typical steric-controlled product distribution to provide ortho-substituted boronate esters. Picolylamine was found to be an ideal ligand to replace 4,4'-di-tert-butylbipyridine to induce the directing effect. Preliminary experiments are consistent with a mechanism involving dissociation of one amine of the hemilabile diamine ligand.

Mechanistic variety in zirconium-catalyzed bond-forming reaction of arsines.

Triamidoamine-supported zirconium complexes have been demonstrated to catalyze a range of bond-forming events utilizing arsines. Three different mechanisms have been observed in these reactions. In the first mechanism, triamidoamine-supported zirconium complexes of the general type (N3N)ZrX (N3N =N(CH2CH2NSiMe3)33-; X = monoanionic ligand) catalyzed the dehydrogenative dimerization of diphenylarsine.

Zirconium-catalyzed heterodehydrocoupling of primary phosphines with silanes and germanes.

Triamidoamine-supported zirconium complexes catalyze the heterodehydrocoupling of primary phosphines with silane and germanes. In this catalysis, P-Si or P-Ge products are observed exclusively with no competitive P-P bond formation. Phosphido complexes (N3N)ZrPHR (N3N = N(CH2CH2NSiMe3)33-, R = Ph, 2; Cy, 3) were observed to be the catalyst resting state, and complex 2 was structurally characterized.