A method for catalytically converting a dihydrotetrazine 1 into a tetrazine 2, wherein the dihydrotetrazine 1 comprises a first R group and a second R group, wherein the first R group is a substituted or unsubstituted aryl, heteroaryl, alkyl, alkenyl, alkynyl, carbonyl, or heteroatom-containing group, and the second R group is selected from the group consisting of H and substituted or unsubstituted aryl, heteroaryl, alkyl, alkenyl, alkynyl, carbonyl, and heteroatom-containing groups;

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wherein the method comprises (a) providing the dihydrotetrazine 1 in a reaction medium, and (b) adding an enzyme as a catalyst and an oxidant to the reaction medium, whereby the dihydrotetrazine 1 is converted to the tetrazine 2.

The present invention generally relates to the microbiological industry, and specifically to the production of L-serine or L-serine derivatives using genetically modified bacteria. The present invention provides genetically modified microorganisms, such as bacteria, wherein the expression of genes encoding for enzymes involved in the degradation of L-serine is attenuated, such as by inactivation, which makes them particularly suitable for the production of L-serine at higher yield. The present invention also provides means by which the microorganism, and more particularly a bacterium, can be made tolerant towards higher concentrations of serine. The present invention also provides methods for the production of L-serine or L-serine derivative using such genetically modified microorganisms.

The present disclosure provides engineered carboxyesterase enzymes that have the ability to catalyze amide bond formation. Also provided are polynucleotides encoding the carboxyesterase enzymes, host cells capable of expressing the engineered carboxyesterase enzymes, and methods of using the engineered carboxyesterase enzymes to make commercially valuable amides. Also provided are amides that are made using the engineered carboxyesterase enzymes.

A strain of Burkholderia is Burkholderia glathei ECU0712, with an accession number of CGMCC NO. 14464. With the strain or its extract as the biocatalyst, thioether is catalyzed to be oxidized asymmetrically to chiral sulfoxide, with significant advantages that the obtained product has a high optical purity, and benefits of a simple reaction system, short preparation time of the catalyst and a high yield of the product.

A genetically modified microorganism includes: an exogenous nucleic acid sequence encoding naphthalene dioxygenase (NDO), wherein the endogenous icd gene of the genetically modified microorganism is knocked out, in which the endogenous icd gene encodes isocitrate dehydrogenase (IDH), and wherein the genetically modified microorganism is capable of using glutamic acid and/or a salt thereof as a nitrogen source to grow and producing indigo dye.

The present disclosure provides engineered polypeptides having imine reductase activity, polynucleotides encoding the engineered imine reductases, host cells capable of expressing the engineered imine reductases, and methods of using these engineered polypeptides with a range of ketone and amine substrate compounds to prepare secondary and tertiary amine product compounds.

Object of the present invention is an efficient process for the preparation of the active pharmaceutical ingredient Sitagliptine and the 2,4,5-trifluorophenylacetic acid (TFAA) and salt thereof, which is a key intermediate for the synthesis of Sitagliptine.

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A process for synthetically producing (S)-nicotine ([(S)-3-(1-methylpyrrolidin-2-yl) pyridine]) is provided.

The disclosure relates to compounds of formula (I): Among the substituents in a compound of formula (I), one of R.sub.4 and R.sub.5 is hydrogen and the other of R.sub.4 and R.sub.5 is OSC.sub.2Rs.sub.6. The disclosure relates to compounds of formula (II): Among the substituents in a compound of formula (II), R.sub.6 is a halogen chosen from F, Cl, Br, and I. The disclosure relates to compositions comprising a compound of formulas (I) or (II) and an excipient. The disclosure relates to pharmaceutical compositions comprising a therapeutically effective amount of a compound of formulas (I) or (II). The disclosure relates to therapeutic uses of compounds of formulas (I) or (II). The disclosure relates to compounds of formula (II), including 5-fluoro-N,N,N-trimethyltryptammonium iodide, 5-fluoro-N,N,N-triethyltryptammonium iodide, 5-fluoro-N,N,N-tri-n-propyltryptammonium iodide, 5-chloro-N,N,N-trimethyltrptammonium iodide, 5-chloro-N,N,N-triethyltryptammonium iodide, 5-bromo-N,N,N-triethyltryptammonium iodide, 5-bromo-N,N,N-tri-n-propyltryptammonium iodide, and 5-bromo-N,N,N-tri-n-propyltryptammonium iodide acetonitrile solvate and their crystalline forms and their compositions and uses.

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A method for catalytically converting a dihydrotetrazine 1 into a tetrazine 2, wherein one R group on the dihydrotetrazine 1 is a substituted or unsubstituted aryl, heteroaryl, alkyl, alkenyl, alkynyl, carbonyl, or heteroatom-containing group, and the other R group is selected from the group consisting of H and substituted or unsubstituted aryl, heteroaryl, alkyl, alkenyl, alkynyl, carbonyl,- or heteroatom-containing groups; 1, 2 wherein the method comprises oxidizing dihydrotetrazine 1 in a reaction medium in the presence of a catalyst and a stoichiometric oxidant. ##STR00001##