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α-Nitroalkyl radicals generated from gem-halo nitro compounds are reactive enough to undergo the carbon-carbon bond forming reaction with allyltributylstannane via radical chain processes, which provides a new method for the introduction of an allyl group into nitroalkanes.

We previously reported the synthesis of the 1,N2-deoxyguanosine adducts of 4-hydroxynonenal, an important product of lipid peroxidation, which involved the nucleophilic aromatic substitution reaction of O 6-protected-2-fluoroinosine with 4-amino-1,2,5-trihydroxydecanal followed by periodate oxidation of the vicinal diol.6 An improved synthesis of the amino triols has been developed. The syn and anti diastereomers of a key intermediate, 4-nitro-5-hydroxy-1-decene, were synthesized by a Henry reaction and separated; each diastereomer was further separated into individual enantiomers by chiral supercritical fluid chromatography. Of note, dihydroxylation of the terminal olefin under conventional conditions with catalytic OsO4 and a tertiary amine oxide as the stoichiometric oxidant led to scrambling of stereochemistry of the nitro group. The scrambling was not observed when t-butylhydroperoxide was used as the oxidant.

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1,3-Dipolar cycloadditions of triisopropylsilyl nitronates and 2-alkylacroleins produced isoxazolines bearing a chiral quaternary center in high yields and enantioselectivities with the aid of a chiral oxazaborolidine catalyst. One chiral isoxazoline product was converted to (R)-(+)-Tanikolide in 9 steps in a total yield of 43%. (Chemical Equation Presented).

The first systematic study of the thermal rearrangement/fragmentation of 5,5-disubstituted 1,4,2-oxathiazoles into isothiocyanates is reported. Structure-activity relationships reveal that the choice of substituent at the 5-position of the 1,4,2-oxathiazoles is the predominant factor to influence the ease of fragmentation.

The present invention is directed to novel substituted dihydropyrrolopyrazoles of structural Formula I which are inhibitors of the dipeptidyl peptidase-N enzyme and which are useful in the treatment or prevention of diseases in which the dipeptidyl peptidase-IV enzyme is involved, such as diabetes and particularly Type 2 diabetes. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which the dipeptidyl peptidase IV enzyme is involved.

Uniform core-shell Pd@IRMOF-3 nanostructures, where single Pd nanoparticle core is surrounded by amino-functionalized IRMOF-3 shell, are prepared by a facile mixed solvothermal method. When used as multifunctional catalysts, the Pd@IRMOF-3 nanocomposites exhibit high activity, enhanced selectivity, and excellent stability in the cascade reaction. Both experimental evidence and theoretical calculations reveal that the high catalytic performance of Pd@IRMOF-3 nanocomposites originates from their unique core-shell structures.

The Henry (nitroaldol) reaction of fluorinated nitro compounds with various aromatic aldehydes and a fluorinated aliphatic aldehyde to give β-fluoro-β-nitroalcohols which bearing a fluorinated quaternary carbon center was reported. The relative configuration of the major diastereoisomer of 2-fluoro-2-nitro-1-(4-nitrophenyl)-3-phenylpropanol (5bf) was determined by X-ray single crystal analysis.

An isotopically labelled building block, 2,3,4,6-tetra-O-acetyl-1-thio-β-d-[13C6]glucopyranose (4), is obtained from the commercially available [13C6]-d-glucose. This hexa-13C-labelled thioglucose can

Equation Presented A synthesis of highly functionalized nitroalkenes is reported that utilizes a cross metathesis (CM) reaction between simple aliphatic nitro compounds and a range of substituted alkenes. This chemistry offers a simple and attractive route to nitroalkenes that would otherwise be difficult to prepare, and that have a very useful application as precursors to a variety of heterocyclic entities.

Several high yielding routes to oxygenated nitropropanes have been developed that include a palladium catalyzed nitro allylation of allylic carbonates, nitration of brominated compounds and a nitro aldol condensation/hydrogenation sequence. Georg Thieme Verlag Stuttgart.

Activation of nitro compounds was accomplished by introduction of angle strain, γ,δ-unsaturation, or a γ-silyl group. Results from a systematic study indicate that coexistence of two or more of these factors in aliphatic nitro compounds allowed transformations to take place under ambient conditions upon catalysis with AlCl3, TiCl4, BF3 · OEt2, or SnCl4. Consequently, structurally modified nitro starting materials led to products in the class of nitroalkyl cyclopentadiene, cyclohydroxamic ester, and chlorohydroxamic acid. (C) 2000 Elsevier Science Ltd.