- Iridium-catalyzed asymmetric hydrogenation of 2-substituted 1,4-benzodioxines
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An Ir-catalyzed asymmetric hydrogenation of 2-substituted 1,4-benzodioxines was developed for the preparation of chiral 1,4-benzodioxanes, which are present in numerous biologically active compounds and natural products. Our tropos biphenyl phosphine-oxazoline ligand is essential for obtaining good ee. A broad range of substrates were tolerable to the reaction conditions and gave the corresponding hydrogenation products in excellent yields and with moderate to good enantioselectivities using the Ir-complex of our tropos phosphine-oxazoline ligand.
- Wang, Yanzhao,Xia, Jingzhao,Yang, Guoqiang,Zhang, Wanbin
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supporting information
p. 477 - 482
(2017/12/26)
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- Novel substituted [1,4] benzodioxino[2,3-e] isoindole derivatives, method for preparing and pharmaceutical compositions containing same
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Compounds of formula (I): wherein: A is as defined in the description, Y represents a group selected from an oxygen atom and a methylene group, R2 represents a hydrogen atom and in that case: R3 represents a group selected from a hydrogen atom and the groups linear or branched (C1-C6)alkyl, aryl, aryl-(C1-C6)alkyl (in which the alkyl moiety is linear or branched) and SO2CF3, or R2 and R3 form a bond, R1 represents a group selected from a hydrogen atom and the groups linear or branched (C1-C6)alkyl, aryl and aryl-(C1-C6)alkyl (in which the alkyl moiety is linear or branched) or a linear or branched (C1-C6)alkylene chain, Z1 and Z2 each represent a hydrogen atom or Z1 and Z2, together with the carbon atoms carrying them, form a phenyl group. Medicaments.
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Page/Page column 9
(2010/10/19)
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- Biaryl-methanethio-, -sulphinyl- and sulphonyl derivatives
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The present invention is related to chemical compositions, processes for the preparation thereof and uses of the composition. Particularly, the present invention relates to compositions that include substituted biaryl-methanesulfinyl acetamides of Formula
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Page/Page column 71
(2008/06/13)
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- o-Quinone methide as a common intermediate in the pyrolysis of o-hydroxybenzyl alcohol, chroman and 1,4-benzodioxin
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The product composition in the very low pressure pyrolysis (550-1210 K) of o-hydroxybenzyl alcohol (HBA), 3,4-dihydro-2H-1-benzopyran (chroman), and 1,4-benzodioxin (BD) indicates that o-quinone methide (o-QM) is the common intermediate in each case. At complete conversion of HBA, o-QM was observed as the only product and the mass spectrum of o-QM could be obtained. At higher temperatures (>950 K), o-QM is subsequently converted into benzene and CO. The thermolysis process for chroman starts with cleavage of the phenoxy-carbon bond and proceeds with ethene elimination, yielding o-QM. The high pressure rate parameters for unimolecular decay have been determined to obey kchroman/s-1 = 1015.3 exp (-269/RT). For BD only the cleavage of the phenyl-vinoxy bond has been observed, and after rearrangement and CO elimination o-QM is formed. The Arrhenius equation for the overall rate of disappearance has been found as kBD/s-1 = 1015.6 exp (-310/RT). Ultimately (1100 K) the thermolysis of BD leads to 1 mole of benzene and 2 moles of CO.
- Dorrestijn, Edwin,Epema, Onno J.,Van Scheppingen, Wibo B.,Mulder, Peter
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p. 1173 - 1178
(2007/10/03)
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