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Several 8-oxabicyclo[3.2.1]oct-6-en-3-ones are prepared by cycloaddition reaction of chiral furanes such as (I) and (VII) with dibromoketone (II).

A variety of C-3 functionalized chiral sulfoxide-containing furan derivatives is prepared, mainly based on manipulation of the carboxyl-moiety in (III).

The title compound is synthesized from a stoichiometric mixture of the elements in an evacuated and sealed quartz tube heated to 1500 °C for 48 h, followed by annealing at 600 °C for 30 d.

A study on the influence of steric and electronic effects of a function attached at C-2 of furans in the yield and diastereoselectivity of [4+3] cycloaddition reactions with oxyallyl cations is presented. In almost all studied furans a cis diastereospecificity and a high endo diastereoselectivity is observed. Increasing bulkyness of the function attached at C-2 of furans, increases the endo diastereoselectivity, but decreases yield. Increasing the electronic density of the furan system, by an electron donating group attached at C-2, increases yield and diastereoselectivity.

An study on the influence of steric and electronic effects of a function attached at C-2 of furans in the yield and diastereoselectivity of [4 + 3] cycloaddition reactions with oxyallyl cations is presented. In almost all studied furans a cis diastereospecificity and a high endo diastereoselectivity is observed. Increasing bulkyness of the function attached at C-2 of furans, the endo diastereoselectivity increases, but yield decreases. Increasing the electronic density of the furan system, by an electron donating group at C-2, both yield and diastereoselectivity increase.

A new synthetic methodology for preparing polyfunctionalized heptane building blocks with up to four stereocenters has been developed. 2,4-Dimethyl-1-methoxy-8-oxabicyclo-[3.2.1]-oct-6-en-3-one has been used as precursor, which can be easily prepared by a [4+3] cycloaddition reaction between 2-methoxy-furan and the oxyallyl cation generated in situ from 2,4-dibromo-3-pentanone. The cycloadducts have an acetal functionality on C1 which allows easy opening of the oxabicyclic system, affording versatile synthons. The application of this methodology to the synthesis of the C17–C23 subunit of Ionomycin is presented.

A study of the induction of asymmetry on the [4+3] cycloaddition reaction of some 13 C2-substituted furan derivatives with 2-oxyallyl cation is presented. The asymmetry was induced by a chiral auxiliary on C2 of furan. A cis diastereospecificity and a high endo diastereoselectivity are observed in almost all studied cases. On decreasing the distance between the stereocenter of the chiral auxiliary and the reactive C2-carbon of the furan ring, the π-facial diastereoselectivity is increased, especially by using chiral furyl-sulfoxides.

During the last few years, biodegradable polymers have been developed to replace petrochemical polymers. Until now, research devoted to these polymers essentially focused on their biodegradability. There is now a need to bear out their nontoxicity. To verify this, the biodegradation must be carried out in accelerated laboratory tests which allow the metabolites and residues to be recovered. To reproduce the natural conditions (compost, field) as closely as possible, degradation experiments must be run on solid-state substrates. We review studies of aerobic degradation in solid-state substrates. This article focuses in particular on the environmental, physical, and chemical parameters (such as substrate nature, moisture, temperature, C/N ratio, and pH) that influence biodegradation kinetics. This study also aims at finding the solid substrate most adapted to residues and metabolite recovery. The most significant parameters would appear to be the substrate type, moisture content, and temperature. Inert substrates such as vermiculite are well suited to residue extraction. This review also opens the field to new research aimed at optimizing conditions for aerobic solid-state biodegradation and at recovering the metabolites and residues of this degradation process.

The crystal structure of the chalcogenide compounds CuFeAlSe3 and CuFeGaSe3, belonging to the system I-II-III-III3, were characterized using X-ray powder diffraction data. Both compounds crystallize in the tetragonal space group P42c (N° 112), Z = 1, with unit cell parameters a = 5.609(1) A, c = 10.963(2) A for CuFeAlSe3 and a = 5.6165(3) A, c = 11.075(1) A for CuFeGaSe3. These compounds are isostructural with CuFeInSe3, and have a normal adamantane structure. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A new unexpected reaction of 1 -(4-fluorophenyl)-2-(4-pyridyl)ethanone 2 with 3-aminopyrazole, involving loss of a 4-pyridylmethyl group, afforded 4,6-bis(4-fluorophenyl)-5-(4-pyridyl)-1H-pyrazolo[3,4-b]pyridine 1 in good yields. Investigation of the features of this cyclization led to the development of a new three component coupling for the synthesis of pyrazolo[3,4-b]pyridines, from a ketone, an aldehyde and a 3-aminopyrazole in the presence of acid catalysis and a protic solvent. The study of the scope of this reaction showed its remarkable versatility and its usefulness in the preparation of other bicyclic systems, such as thieno[3,2-b]pyridines, pyrrolo[3,2-b]pyridines, imidazo[4,5-b]pyridines, furo[2,3-b]pyridines, isoxazolo[5,4-b]pyridines and, isothiazolo[5,4-b]pyridines. The three component nature of this reaction makes it suitable for the preparation of combinatorial libraries since scaffold decoration can be easily achieved in one step.

The crystal structure of the quaternary compound CuTaInSe3 belonging to the system (CuInSe2)1-x(TaSe)x with x= 0.5, was analyzed using X-ray powder diffraction data. This material is isostructural with the CuFeInSe3 compound, and crystallize in the tetragonal space group P42c (No 112), Z = 1, with unit cell parameters a = 5.7831(1) A, c = 11.6227(4) A, V = 388.71(2) A3. The Rietveld refinement of 18 instrumental and structural variables led to Rp = 8.0%, Rwp = 9.5%, Rexp = 6.3% and χ2 = 1.5 for 4501 step intensities and 144 independent reflections. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The crystal structure of the semiconductor compound CuFe 2 InSe 4 was analyzed using X-ray powder diffraction data. The powder pattern refinedby the Rietveld method was composed of 86.6% of the principal phase CuFe 2 InSe 4 and 13.4% of the binary phase FeSe. CuFe 2 InSe 4 crystallizesin the tetragonal space group I42 ¯ m (no. 121), Z =2, with unit cell parameters a =5.7694(3)A, ˚ c =11.495(1)A, V =382.62(4)A 3 . FeSe crystallizesin the tetragonal space group P 4/ nmm (no. 129), Z =2, and a =3.784(1)A,˚ c =5.502(2)A,˚ V =78.78(4)A˚ 3 . The refinement of 28 instrumental andstructural parameters led to R p =8.2%, R wp =10.7%, R exp =6.7% and S =1.7; R B =9.9% (CuFe 2 InSe 4 ), R B =8.8% (FeSe) for 76 and 36 independentreflections, respectively.© 2006 Elsevier B.V. All rights reserved. PACS: 61.10.Nz; 61.50.Nw; 61.66.Fn Keywords: Semiconductors; Crystal structure; X-ray powder diffraction; Rietveld refinement 1. Introduction The addition of a II–VI binary compound to ternary chal-copyrite structures (I–III–VI

An improved methodology to carry out [4C(4π;)+3C(2π;)] cycloaddition reactions of dienes and oxyallyl cations, is presented. The reaction starts from commercially available dienes and easy-handling α,α′-diiodoketones, which are reduced by Zn (powder) or Zn/Cu couple to generate an oxyallyl cation as an intermediate. The reaction is carried out under mild thermal or sonochemical conditions at low temperatures (from 0 to −44°C) and for short reaction times (