A substrate-controlled asymmetric Prins/Conia-ene cascade cyclization has been developed with In(OTf)(3) in CH(3)CN from 0 to 70 °C. These conditions afforded very good yields of the 1-oxadecalin product in one pot and effectively suppressed the racemization of the 1-oxadecalin product with almost no enantiomeric excess (ee) loss. This cascade cyclization has been successfully employed for the ...

A series of 2-cyclohexylideneperhydro-4,7-methanoindene derivatives was synthesized as novel androgen receptor ligands. Asymmetric hydroboration of key intermediate 2 afforded single enantiomer alcohol derivatives (3aR)-3 and (3aS)-3 which could be further transformed to give 12 variously substituted keto alcohol target compounds. X-ray crystallography of the 4-bromobenzenesulfonyl ester (3aS)-...

Diacyl phthiocerol esters and their congeners are mycobacterial virulence factors. The biosynthesis of these complex lipids remains poorly understood. Insight into their biosynthesis will aid the development of rationally designed drugs that inhibit their production. In this study, we investigate a biosynthetic step required for diacyl (phenol)phthiocerol ester production, i.e., the reduction o...

A gas chromatographic method which makes possible simultaneous analysis of common types of acidic and neutral sugars is described. Particular advantages are achieved with hydroxy acids, ketoses, and uronic acids. Acids and lactones are first converted into their sodium salts. Free or potential aldehydo and keto groups are transformed to oximes or O-methyloximes. Fully substituted acyclic ester ...

Physical and coding properties of poly (5-aminouridylic acid) and of 5-aminouridine-containing trinucleotides. Crystal structure and conformation of 3-deaza-4-deoxyuridine. 5-Substituents in the uridine moiety and their effect on the conformation of ApU type dinucleoside phosphates. Restriction or amplification of wobble recognition: The structure of 2-thio-5-methylaminomethyluridine and the in...

An asymmetric synthesis of the cytotoxic natural product, (-)-FR182877 (1), has been achieved. Chirality for the entire structure was established using two (4R)-4-benzyl-2-oxazolidinone-mediated boron aldol reactions. A 19-membered macrocarbocycle was synthesized by the coupling of two fragments using a regioselective Suzuki coupling (17 + 23 --> 26; 84%) and macrocyclization of a beta-keto est...

Fructose, a rarely occurring sugar constituent of Gram-negative bacterial lipopolysaccharides (LPS), is distributed ubiquitously in LPS of 01 Vibrio cholerae so far examined, but its location in LPS has not hitherto been elucidated. It was found that hydrazinolysis of LPS successfully affords a derivative retaining virtually all the fructose of intact LPS, but no ester-bound phosphate. Structur...

In the preceding paper (I), evidence concerning the proof of structure of 2-keto-3-deoxyheptonic acid was presented and it was indicated that this compound is a major product of ribose 5-phosphate metabolism in extracts of Escherichia coli strain B. This report is concerned with the enzymic synthesis of 2-keto-3deosyheptonic acid in extracts of Escherichia coli strain B and is the first direct ...

Rat liver glutamine transaminase acts on y-glutamyl hydrazones of a-keto acids to yield the corresponding L-amino acids and 3-hydroxy-tetrahydro-6-pyridazinone-3-carboxyllc acid; the latter compound undergoes nonenzymatic dehydration in acid to yield 1,4,5,6-tetrahydro-6-pyridazinone -3carboxylic acid. L-Amino acid oxidase (snake venom) also catalyzes the formation of 3-hydroxy-tetrahydro-6-pyr...

The oxidation of a stoichiometric diethyl ether-oxygen-nitrogen mixture containing 5000 ppm fuel was studied in jet-stirred reactor at 10 atm and residence times 1 s. Experimental temperatures varied stepwise for 440 to 740 K products were quantified by gas chromatography with TCD FID, chromatography-mass spectrometry, FTIR. Other experiments the temperature range 480 570 performed characterizi...