The invention provides an improved method of isolating the 3-(E)-isomer of an unsaturated carboxylic acid from a mixture of corresponding (E/Z)isomers. More particularly, the present invention relates to an improved method for the biocatalytic preparation of (3E,7E)-homofarnesylic acid; as well as a novel biocatalytic method for the improved preparation of homofarnesol, in particular of (3E,7E)-homofarnesol and homofarnesol preparations having an increased content of (3E,7E)-homofarnesol. The present invention also relates to methods of preparing()-ambroxby applying (3E,7E)-homofarnesylic acid or (3E,7E)-homofarnesol as obtained according to the invention as starting material.

The invention provides methods of synthesizing compounds in an asymmetric or enantioenriched fashion, wherein the compounds are useful intermediates in the synthesis of viral protease inhibitors.

The invention provides methods of synthesizing a viral protease inhibitor in high yield, without using expensive catalysts or challenging reaction conditions.

The present invention relates to a process for carbonylating allyl alcohols at low temperature, low pressure and/or low catalyst loading. In an alternative embodiment, an acylation product of the allyl alcohol is used for the carbonylation. The present invention likewise relates to the preparation of conversion products of these carbonylation products and specifically of ()-ambrox.

Disclosed are methods of synthesizing enantioenriched difluoroalkylcyclopropyl amino esters and their salts, such as the dicyclohexylamine salt of (1S,2R)-2-(difluoromethyl)-1-(propoxycarbonyl)cyclopropane carboxylic acid. These compounds are useful intermediates in the synthesis of viral protease inhibitors.

Provided are an esterase mutant and use thereof. The amino acid sequence of the esterase mutant has a sequence as shown in SEQ ID NO: 1, and sites at which amino acid mutations occur include an N51G site.

Methylopila sp. and use thereof in the selective resolution preparation of (S)--ethyl-2-oxo-1-pyrrolidineacetate. Methylopila sp. that produces enzymes is subjected to cell immobilization, and is then applied to the biological resolution of a racemate (R,S)--ethyl-2-oxo-1-pyrrolidineacetic acid ethyl ester to prepare high optically pure (S)--ethyl-2-oxo-1-pyrrolidineacetic acid ethyl ester, which is further subjected to a hydrolysis reaction to obtain (S)--ethyl-2-oxo-1-pyrrolidineacetate. The present invention achieves a high conversion yield up to 50.0% or more, a good stereoselectivity, and an enantiomeric excess value e.e..sub.s(%) of (S)--ethyl-2-oxo-1-pyrrolidineacetic acid ethyl ester not less than 99.5; the catalytic efficiency is high; the concentration of the racemic substrate in the resolution reaction is up to 500 g/L, the reaction time does not exceed 15 h, the number of reuse times of the immobilized cells is not lower than 35.

The invention provides methods of synthesizing a viral protease inhibitor in high yield, without using expensive catalysts or challenging reaction conditions.

The invention provides methods of synthesizing compounds in an asymmetric or enantioenriched fashion, wherein the compounds are useful intermediates in the synthesis of viral protease inhibitors.

This invention refers to the obtainment of a modified lipolytic enzyme that was isolated, expressed and purified from the heterologous expression. The gene sequence that codifies for the basal enzyme was obtained based on a thermo acidophilus organism of the acidobacteraceae family. This basal enzyme that comes from a thermo acidophilus organism, it is able to hydrolyze lipid substrates (triacylglycerols) united to middle chain fatty acids (C.sub.6-C.sub.10) such as tributyrine and tricapryln, among others. It also can carry out other inverse reactions to the hydrolysis such as synthesis reactions. On the other hand, this enzyme has enantioselective preference on (S) substrates of profens esters such as ibuprofen, naproxen and others. The enantioselective lipolytic basal enzyme was modified in its terminal C end to add an amino acid histidine tail that gives a higher efficiency in its purification process. The invention therefore refers to a method for making a pure, active polypeptide, which is called lipolytic enzyme 499EST obtained through the host E. coli BL 21 (DE3).