52619-46-2

Upstream product

• 1460-34-0 2-oxo-3(RS)-methylvaleric acid 
• 50-00-0 formaldehyd 
• 99-73-0 para-bromophenacyl bromide 
• 1253963-47-1 methyl 3S,11S-dihydroxytetradecanoate 11-O-β-D-quinovopyranosyl-(1->4)-O-(2-O-2S-methylbutyryl)-α-L-rhamnopyranosyl-(1->2)-O-β-D-glucopyranosyl-(1->2)-{[4-O-2R-methyl-3R-O-(2R-methyl-3R-hydroxybutyryl)butyryl]-O-α-L-rhamnopyranosyl-(1->6)}-β-D-glucopyranoside 
• 1253963-45-9 methyl 3S,11S-dihydroxytetradecanoate 11-O-α-L-rhamnopyranosyl-(1->3)-O-[4-O-2R-methyl-3R-O-(2R-methyl-3R-hydroxybutyryl)butyryl]-β-D-quinovopyranosyl-(1->4)-O-(2-O-2S-methylbutyryl)-α-L-rhamnopyranosyl-(1->2)-O-β-D-glucopyranosyl-(1->2)-[O-(4-O-2S-methyl-3S-hydroxybutyryl)-α-L-rhamnopyranosyl-(1->6)]-β-D-glucopyranoside 
• 1730-91-2 (S)-2-Methylbutyric acid 

Relevant academic research and scientific papers

Biocatalytic Construction of Quaternary Centers by Aldol Addition of 3,3-Disubstituted 2-Oxoacid Derivatives to Aldehydes

The congested nature of quaternary carbons hinders their preparation, most notably when stereocontrol is required. Here we report a biocatalytic method for the creation of quaternary carbon centers with broad substrate scope, leading to different compound classes bearing this structural feature. The key step comprises the aldol addition of 3,3-disubstituted 2-oxoacids to aldehydes catalyzed by metal dependent 3-methyl-2-oxobutanoate hydroxymethyltransferase from E. coli (KPHMT) and variants thereof. The 3,3,3-trisubstituted 2-oxoacids thus produced were converted into 2-oxolactones and 3-hydroxy acids and directly to ulosonic acid derivatives, all bearing gem-dialkyl, gem-cycloalkyl, and spirocyclic quaternary centers. In addition, some of these reactions use a single enantiomer from racemic nucleophiles to afford stereopure quaternary carbons. The notable substrate tolerance and stereocontrol of these enzymes are indicative of their potential for the synthesis of structurally intricate molecules.

Pharesinosides A-G, acylated glycosidic acid methyl esters derivatized by NH2 silica gel on-column catalyzation from the crude resin glycosides of Pharbitis Semen

Application of NH2 silica gel column chromatography using CH2Cl2-MeOH was found to show a satisfactory resolution for separation of the crude resin glycosides of Pharbitis Semen (the seeds of Pharbitis nil), led to the isolation of seven new acylated glycosidic acid methyl esters, Pharesinosides A-G (1–7), along with four known ones (8–11). These compounds (1–11) were considered to be generated via methyl esterification of the carboxyl group in acylated glycosidic acids. Their structures including stereochemistry were elucidated on the basis of a combination of the spectroscopic and chemical methods. All isolates were evaluated for anti-tumor migration activities with human colon cancer cell line HCT-116, and compound 7 exhibited a potent migration inhibitory activity.

Varitatin A, a Highly Modified Fatty Acid Amide from Penicillium variabile Cultured with a DNA Methyltransferase Inhibitor

A new, highly modified fatty acid amide, varitatin A (1), was isolated from the fungus Penicillium variabile HXQ-H-1 cultivated with the DNA methyltransferase inhibitor 5-azacytidine. The structure including the absolute configuration of 1 was established by analysis of NMR and MS data, together with chemical degradation and Mosher's method based on MPA esters. Compound 1 showed cytotoxicity against HCT-116 cells with an IC50 value of 2.8 μM and also inhibited the effects of protein tyrosine kinases.

Acylated glycosides of hydroxy fatty acid methyl esters generated from the crude resin glycoside (pharbitin) of seeds of pharbitis nil by treatment with indium(III) chloride in methanol

Treatment of the crude ether-insoluble resin glycoside (convolvulin) from seeds of Pharbitis nil (Pharbitis Semen), called pharbitin, with indium(III) chloride in methanol provided seven oligoglycosides of hydroxy fatty acid methyl esters partially acylated by 2-methyl-3-hydroxybutyric (nilic) and 2S-methylbutyric acids. Their structures were elucidated on the basis of NMR and MS data and chemical conversions.

Absolute configuration of scyphostatin

(Formula presented) The absolute configuration of the side chain of scyphostatin (1) has been established. The chemical degradation of 1 gave 4 and 9, which correspond to the C7′-C12′ and C13′-C16′ fragments of the natural products, respectively. The spec