Vinylene carbonate preparation

The classical diene synthesis has been used for building the six-membered ring in the preparation of a/to-inositol by Criegee and Becher.36 trans, trans-Diacetoxybutadiene (XVI) and vinylene carbonate (XVII) condensed at 205-210° to an addition product (XVIII). Hydroxylation of this compound by osmium tetroxide, followed by hydrolysis, gave aWo-inositol the bulky osmium tetroxide approaches from the unhindered side of the molecule and the other possible product of the hydroxylation, m-inositol, is not formed.4 trans-Hydroxy 1 ation of XVIII would give epi-inositol. 

Several new variations of methods for preparation of indoles by Pd-mediated cyclization were reported. Vinylene carbonate was found to be a satisfactory C2-C3 precursor for synthesis of N-acylindolin-2-ols and A-acylindoles from o-iodoacetanilides under Heck conditions. <95H(41)1627>... 

Scheme 169 Preparation of vinylene carbonate derived from 2,3-butane diol.

The substituted vinylene carbonate (I) can be used for the preparation through chlorination and dehydrochlorina-tion of the intermediate (II) which is the key reagent for the production of Lenampicillin [Scheme 170]. 

It has been demonstrated in previous sections of this chapter that some substrates (e.g., furfuryl alcohols, vinylene carbonate telomers, etc.) are capable of being transformed, in a limited number of synthetic steps, into the full variety of stereoisomeric sugars. These syntheses are fairly general. In this section, carbohydrate preparations are described which start from some peculiar substrates and by exploitation of specific reactions lead to a single monosaccharide or, at most, to a limited number. Natural products have often been used for the purpose. Their structural features usually predetermine the type of sugar that can be obtained. These substrates, being optically active, afford eventually enantiomeric products. The usually troublesome resolution of racemic intermediates of final... 

Octamethylbicyclo[4,2,0]octa-2,4,7-triene has been prepared from octamethyl-cyclo-octatetraene via its dimethyl azocarboxylate adduct. The rearrangement of octamethylbicyclo[4,2,0]octa-2,4,7-triene back to the monocyclic octamethylcyclo-octatetraene was studied and the Diels-Alder adducts with TCNE and maleic anhydride were prepared. Cyclo-octatetraene and vinylene carbonate react at 180°C to give the polycyclic adduct (150 50%) mechanisms for this reaction were discussed. 

Preparative Method prepared by reaction of phosphoms(V) sulfide with vinylene carbonate. ... 

When vinylene carbonate was included at an amount of 0.01-9% and fluoroethylene carbonate was included at an amount of 0.1-7%, and a nitrile-based compound, such as adiponitrile, was included in an amount of 0.005-10% to prepare an electrolyte, a cell including the electrolyte demonstrated an excellent storage stability even at a high temperature (104). 

Monomers were synthesized in standard esterification procedures from exo,exo-23-dihydrojy-5-norbomene (prepared from bicyclo[2.2.1]hepta-2,5-diene by selective oxidation of one double bond with KMn04 (10) or with 0s04/N-Meth-ylmorpholine-N-oxide) (11) or from emfo-5-norbomenylene-2,3-carbonate (prepared from qrclopentadiene and vinylene carbonate in a Diels-Alder condensation) (12). 

As mentioned before, the incorporation of carbon nanotubes in conjugated polymers can lead to improved properties of such composites, one of them being great enhancement of the transport characteristics, which is of primary importance in organic light-emitting diodes (OLEDs) for example. Due to their solubility, which allows easy preparation, composites based on PPV (poly(phenylene vinylene)) derivatives have been extensively studied. Detailed investigation of PmPV (poly(m-phenylene... 

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