4658-69-9

Disclosed are compounds of Formula (1), and pharmaceutically acceptable salts thereof, wherein n, R1, R4, R5, R6, R7, R8, R9, R10, R11, R14, Xsu

β-Branched noncanonical amino acids are valuable molecules in modern drug development efforts. However, they are still challenging to prepare due to the need to set multiple stereocenters in a stereoselective fashion, and contemporary methods for the synthesis of such compounds often rely on the use of rare-transition-metal catalysts with designer ligands. Herein, we report a highly diastereo- and enantioselective biocatalytic transamination method to prepare a broad range of aromatic β-branched α-amino acids. Mechanistic studies show that the transformation proceeds through dynamic kinetic resolution that is unique to the optimal enzyme. To highlight its utility and practicality, the biocatalytic reaction was applied to the synthesis of several sp3-rich cyclic fragments and the first total synthesis of jomthonic acid A.

The invention relates to a tricyclic derivative inhibitor as well as a preparation method and applications thereof, in particular to a compound shown in a general formula (I) in the description, a preparation method of the compound, pharmaceutical composi

A sequential benzoylation and multihetero-Cope rearrangement of α-keto ester derived nitrones has been developed. The reaction furnishes a diverse array of complex α-imino ester derivatives. The products can be transformed into amino alcohols via LiAlH 4 reduction.

S-Adenosylmethionine-dependent methyltransferases (MTs) play a decisive role in the biosynthesis of natural products and in epigenetic processes. MTs catalyze the methylation of heteroatoms and even of carbon atoms, which, in many cases, is a challenging reaction in conventional synthesis. However, C-MTs are often highly substrate-specific. Herein, we show that SgvM from Streptomyces griseoviridis features an extended substrate scope with respect to the nucleophile as well as the electrophile. Aside from its physiological substrate 4-methyl-2-oxovalerate, SgvM catalyzes the (di)methylation of pyruvate, 2-oxobutyrate, 2-oxovalerate, and phenylpyruvate at the β-carbon atom. Chiral-phase HPLC analysis revealed that the methylation of 2-oxovalerate occurs with R selectivity while the ethylation of 2-oxobutyrate with S-adenosylethionine results in the S enantiomer of 3-methyl-2-oxovalerate. Thus SgvM could be a valuable tool for asymmetric biocatalytic C-alkylation reactions.

HTI-286 is a synthetic analogue of the natural product hemiasterlin. HTI-286 is a potent antitumor agent that induces tubulin oligomerization. To investigate the binding stoichiometry and the binding site during this ligand-induced tubulin association, we

Investigation of the α,β-unsaturated-α-amino acids-dehydrovaline, dehydrophenylalanine, and dehydropipecolinic acid-revealed that these compounds undergo rapid hydrolysis in neutral aqueous medium, via the imine tautomers, even when the corresponding este

The cyclic ketene acetals 3, 5 are prepared from the dioxolanone 2 resp. the oxazolidinediones 4 by silylation with trimethylsilyl triflate (1)/triethylamine.In an aldol addition/Peterson olefination reaction catalysed by 1 the ketene acetals 3, 5 yield the (E/Z)-benzylidene derivatives 7, 12, 13 in reaction with aromatic aldehydes 6.In a side reaction the α-(trimethylsilyl)benzylidene derivatives 8 are formed from 3 and 6.Compounds 7 can be hydrolysed to yield α-ketocarboxylic acids 14.The latter are also obtained via β-elimination of trimethylsilanol from 2,3-bis(trimethylsiloxy)carboxylic acid anhydride/DMAP/pyridine. Key Words: 1,3-Dioxolanes / 1,3-Oxazolidines / α-Oxocarboxylic acids

A synthesis of (-)- and (+/-)-(Z)-9-methylchorismic acid (3) is reported.The half-life for the uncatalyzed Claisen rearrangement of (+/-)-3 in H2O (pH 7.5, 30 deg C) is 5.7 h.Chorismate analogue (-)-3 was a modest substrate for chorismate mutase (chorismate mutase-prephenate dehydrogenase from E. coli): Km = 4.0 mM, kcat./kuncat. = 4.2*104.It was established that the enzyme-catalyzed Claisen rearrangement of (-)-3 proceeds through a chairlike transition state in similar fashion to the chorismate mutase catalyzed rearrangement of (-)-chorismic acid (1).

α-Ketoacids can be easily synthesized with satisfactory yields and selectivities by carbonylation of aryl halides and secondary benzyl halides under very mild conditions.The reactions are catalyzed by Co2(CO)8 in alcoholic solvents; the presence of a methyl source (dimethyl sulfate or methyl iodide) is necessary for the carbonylation of the aryl halides.Base, temperature and solvent have large effects on the course of the reaction.

Application of the phase-transfer technique to the cobalt carbonyl-catalyzed carbonylation of secondary benzyl halides gives either monocarbonyl and double carbonyl insertion or coupling of organic halides as the major reaction, depending on the experimental conditions.Alcohols or ethers mainly give salts of carboxylic acids.Use of higher pressures of CO association with a hydrocarbon organic phase, favours coupling rather than carbonylation.A possible reaction mechanism is discussed.