Herminia I. Pérez

Evaluation of guanabana (Annona muricata) seed meal as a source of (S)-oxynitrilase

Guanabana seed meal is a source of (S)-oxynitrilase which biocatalyzes the enantioselective addition of HCN to aromatic, heteroaromatic and α,β-unsaturated aldehydes to produce cyanohydrins.

New sources of (R)-oxynitrilase: capulin (Prunnus capuli) and mamey (Mammea americana)

Abstract(R)-Cyanohydrins were prepared from aldehydes and HCN in diisopropyl ether with high enantiomeric purity (89–98 %ee) by using the defatted meal from capulin (Prunnus capuli) or mamey (Mammea americana) as sources of (R)-oxynitrilase.

Resolution of methylarylmethanols via oxidation with Nocardia corallina

Abstract Ten different racemates of methylarylmethanols were subjected to whole cells of Nocardia corallina B-276 to give, via enantioselective oxidations, the corresponding ketone and the enantiomerically enriched secondary alcohol in moderate yields and excellent e.e.s. The configuration of the resulting alcohol is ( R ). This procedure permits a very good separation of the racemates of meta - and para -monosubstituted methylarylmethanols.

Nitrile hydratase activity of Nocardia corallina B-276

The nitrile hydratase activity of Nocardia corallina B-276 is described, and the only detected product during the biocatalyzed hydrolysis of selected nitriles was the corresponding amide. The best results were obtained using a suspension of cells in a phosphate buffer (pH= 7.0), with conversion percentages ranging from 31% to > 99%.

Enantioselective oxidation of diaryl carbinols by Nocardia corallina B-276

Abstract Whole cells of Nocardia corallina B-276 oxidized diaryl carbinols enantioselectively to give ketones in moderate yields, and some of the unreacted alcohols showed high ees. This asymmetric oxidation is a simple and efficient method for preparing meta- and para- monosubstituted optically active diaryl carbinols from the racemates. The para- substituted chiral alcohols have an R configuration.

Oxidation of substituted benzyl alcohols to carboxylic acids by Nocardia corallina B-276

Whole cells of Nocardia corallina B-276, oxidized 21 substituted benzyl alcohols, at 1 mM scale, to carboxylic acids at 28-30°C, giving yields of products from 5 to 77%.

Hydrolysis of Ibuprofen Nitrile and Ibuprofen Amide and Deracemisation of Ibuprofen Using Nocardia corallina B-276

A novel application of whole cells of Nocardia corallina B-276 for the deracemisation of ibuprofen is reported. This microorganism successfully hydrolysed ibuprofen nitrile to ibuprofen amide, and ibuprofen amide to ibuprofen, using a suspension of cells in a potassium phosphate buffer solution (0.1 M, pH = 7.0). These results can be explained by the presence of NHase and amidase enzymes, but the reactions are not enantioselective and low ee values were obtained. However, (R)-ibuprofen was isolated with >99% ee by a deracemisation process catalysed by N.corallina B-276. This is the first report of this kind of catalysis with this microorganism.

A Facile One-Pot Synthesis of 4-Hydroxy-3-methoxycarbonyl-2-methyl-2h-1,2-benzothiazine 1,1-Dioxide, a Key Intermediate in the Synthesis of Oxicam Anti-Inflammatory Agents

Abstract 4-Hydroxy-3-methoxycarbonyl-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (8) was synthesized by a one-pot procedure, starting from the readily available saccharine. The synthesis involves 4 transformations with an overall yield equivalent to that from the stepwise process.

Hydroxynitrile Lyases from Prunus Seeds in the Preparation of Cyanohydrins

The hydroxynitrile lyase (HNL) activity of nine defatted Prunus seeds was compared for catalyzing the addition of HCN to aromatic, heteroaromatic and α,β-unsaturated aldehydes. Although the conversion and enantiomeric excess (ee) of the corresponding cyanohydrins were both influenced by the HNL source and the chemical structure of the aldehyde, Prunus HNLs were all suitable for the enantioselective preparation of cyanohydrins.

Biotransformation of (S)-cis-verbenol with Nocardia corallina B-276

The biotransformation of (S)-cis-verbenol with Nocardia corallina was investigated using two methods: Suspension of cells in a phosphate buffer (pH 7) with various substrate:cells ratios; and bioreactor of 3-L with cells in the culture media. Both gave (1S)-(-)-verbenone with excellent yields ranging from >99 to 98%, at scale of 0.7 and 7 mmol respectively.