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1012-72-2

 Photolysis of the Diels-Alder adduct of 3,6-di-tert-butyl-o-benzoquinone and cyclobutadiene at ice-bath temperatures afforded the bicyclooctatriene 12.During warming to room temperature, this hydrocarbon underwent kinetically first-order valence isomerization to provide 5 and its bond shift isomer 4.This finding adumbrated the facility with which 4 and 5 are interconverted.Reaction of this cyclooctatetraene mixture with N-methyltriazolinedione gave urazoles 16 and 17 as chromatographically separable entities.Like 13, the related cycloadduct of 12 wherein both bridgehead tert-butyl groups exhibit restricted rotation , the angular tert-butyl substituent in 17 is sterically perturbed.Hydrolysis-oxidation of either 16 or 17 returned only mixtures of 4 and 5 because of their rapid bond shifting rates.When the equilibrium constant between these two isomers was determined by 1H NMR spectroscopy, it was found that 5, the apparently more congested compound, was the more stable in CDCl3 solutio
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104010-72-2 Chemoenzymatic synthesis of a versatile cyclopentenone

https://www.lookchem.com/CASDataBase_104010-72-2.htm cyclopentenone has been prepared by enzymatic resolution of cis-4-phenyloxy- and cis-4-(4-methoxyphenyloxy)-cyclopent-2-en-1-ol in isopropenyl acetate using Pseudomonas cepacia lipase. The use of a 4-methoxyphenyloxy-alcohol intermediate enabled the use of both enzymatically resolved enantiomers in the synthesis of the desired (+)-enone. 
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450-95-3 Linking of Alcohols with Vinyl Azides

https://www.lookchem.com/CASDataBase_450-95-3.htm  A protocol to link alcohols with vinyl azides has been established through fluoro- or bromo-alkoxylation of vinyl azides to provide α-alkoxy-β-haloalkyl azides. A series of primary and secondary alcohols including natural products and their derivatives such as sugars and steroids were successfully anchored with vinyl azides. The as-prepared cyanine dye linked testosterones were capable of rapid cell membrane imaging in real time. 
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75-35-4 Laser-induced Decomposition of 1,1,2-Trichloroethane

https://www.lookchem.com/CASDataBase_75-35-4.htm  CH 2 ClCHCl 2  was photolyzed with a focusing geometry using the P(24) line of the 10.6 μm CO 2  band (940.6 cm -1 ).The final products of neat photolysis were cis- and trans-CHCl=CHCl, CH 2 =CCl 2 , CH 2 =CHCl, CH<*>CCl, CH<*>CH, and C 4 H 2 .The relative yield of CH 2 =CCl 2  in particular was strongly dependent on CH 2 ClCHCl 2  pressure and sensitive to the addition of H atom containing molecules.A series of diagnostic experiments shows that the dichloroethene isomers are formed by three different processes, i.e., infrared multiphoton decomposition, collision-induced decomposition, and radical chain reaction.Infrared multiphoton decomposition and collision-induced decomposition give rise to cis- and trans-CHCl=CHCl predominantly, while the radical chain reaction generates the dichloroethane isomers in comparable amounts at high reactant pressures, the most probable initiation step being the C-Cl bond-scission reaction of
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4205-23-6

 https://www.lookchem.com/CASDataBase_4205-23-6.htm A highly selective self-condensation of glycolaldehyde to different C 4  molecules has been achieved using Lewis acidic stannosilicate catalysts in water at moderate temperatures (40–100 °C). The medium-sized zeolite pores (10-membered ring framework) in Sn-MFI facilitate the formation of tetrose sugars while hindering consecutive aldol reactions leading to hexose sugars. High yields of tetrose sugars (74 %) with minor amounts of vinyl glycolic acid (VGA), an α-hydroxyacid, are obtained using Sn-MFI with selectivities towards C 4  products reaching 97 %. Tin catalysts having large pores or no pore structure (Sn-Beta, Sn-MCM-41, Sn-SBA-15, tin chloride) led to lower selectivities for C 4  sugars due to formation of hexose sugars. In the case of Sn-Beta, VGA is the main product (30 %), illustrating differences in selectivity of the Sn sites in the different frameworks. Under optimized conditions, GA can undergo further conversion, leadi
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74111-21-0

 https://www.lookchem.com/CASDataBase_74111-21-0.htm (Chemical Equation Presented) Linear (n = 2-18) and cyclic oligomers (n = 3-8) of a cyclohexylether-δ-amino acid (COA) were prepared in high yield and stereopurity. CD spectra of the linear oligomers were indicative of secondary structure formation. X-ray crystal structures of cyclic COA oligomers revealed hydrophobic packing and internal 5- and 10-membered-ring hydrogen bonds. Ether and amide oxygens reside preferably in an ap orientation. This conformational locking is apparently broken by a C-2 substituent in an asymmetric cyclotrimer, for which a zeolithe-like tubular structure was found.
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100-64-1 On the Oxidation of Hydroxylamines with o -Iodoxybenzoic Acid

https://www.lookchem.com/CASDataBase_100-64-1.htm o -Iodoxybenzoic acid (IBX) is confirmed as a powerful tool for the oxidation of hydroxylamines. The synthetic route is demonstrated as efficient and user friendly, and is exploited on various carbohydrate-derived N,N-disubstituted hydroxylamines (cyclic, acyclic, and functionalized ones), affording the corresponding nitrones in good yields and regioselectivity. N-Monosubstituted hydroxylamines revealed an interesting divergent behavior depending on the reaction conditions. While IBX oxidation in dimethyl sulfoxide at 45 °C furnished oximes as reported, the oxidation in dichloromethane at room temperature afforded efficiently the unusual corresponding nitroso dimers. 
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