نتایج جستجو برای: 18 diazabicyclo540 undec 7 ene dbu hydrobromide perbromide

تعداد نتایج: 931924  

2010
Ahmet Bilgin Çiğdem Yağcı Ayşegül Mendi Ufuk Yıldız

Synthesis of metal-free and metallophthalocyanines bearing a-methylferrocenylmethoxy units was described. Precursor 3 required for the preparation of phthalocyanines 4–9, was synthsized by the nucleophilic aromatic substitution reaction between a-methylferrocenylmethanol and 4-nitrophthalonitrile in dry DMF. The metal-free phthalocyanine 4 was prepared from 4-(amethylferrocenylmethoxy)phthaloni...

Journal: :Acta Crystallographica Section E Structure Reports Online 2014

Journal: :The journal of physical chemistry. B 2011
Dmitry Lipkind Nigam Rath James S Chickos Vasiliy A Pozdeev Sergey P Verevkin

The vaporization enthalpies of a series of heterocyclic compounds some suspected of showing evidence of a higher degree of self-association in comparison to many other nitrogen heterocycles have been measured both by correlation gas chromatography (CGC) and for comparison by transpiration. The compounds share some structural similarities. They include 2- and 4-(N,N-dimethylamino)pyridine, 1,5-d...

Journal: :Organic & biomolecular chemistry 2017
José-Luis Giner Ju Feng

The squalene cyclase of Tetrahymena pyriformis cyclizes 2,3-dihydrosqualene to euph-7-ene. This was used as a model for euphane biosynthesis. D-ring formation was demonstrated to involve pre-chair folding through an experiment with 2,3-dihydro-5-oxasqualene. This requires that a non-least motion rotation (120°) of the C17-20 bond in the intermediate deoxydammaranyl cation occurs before the firs...

2017
Xueqin Zhang Chuanfu Liu Aiping Zhang Runcang Sun

Recently, organic catalysis has become a powerful alternative to the use of more traditional metal-based catalysts. In this study, 4-dimethylaminopyridine (DMAP), 1,8-diazabicyclo[5.4.0]undec7-ene (DBU), and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were applied to mediate the ring-opening graft polymerization (ROGP) of p-dioxanone (PDO) with xylan-based hemicelluloses in ionic liquid 1-butyl-3...

Journal: :Biomacromolecules 2015
Ana Pascual Jeremy P K Tan Alex Yuen Julian M W Chan Daniel J Coady David Mecerreyes James L Hedrick Yi Yan Yang Haritz Sardon

In this study, a new family of broad-spectrum antimicrobial polycarbonate hydrogels has been successfully synthesized and characterized. Tertiary amine-containing eight-membered monofunctional and difunctional cyclic carbonates were synthesized, and chemically cross-linked polycarbonate hydrogels were obtained by copolymerizing these monomers with a poly(ethylene glycol)-based bifunctional init...

Journal: :Journal of the American Chemical Society 2013
Haritz Sardon Amanda C Engler Julian M W Chan Jeannette M García Daniel J Coady Ana Pascual David Mecerreyes Gavin O Jones Julia E Rice Hans W Horn James L Hedrick

A systematic study of acid organocatalysts for the polyaddition of poly(ethylene glycol) to hexamethylene diisocyanate in solution has been performed. Among organic acids evaluated, sulfonic acids were found the most effective for urethane formations even when compared with conventional tin-based catalysts (dibutyltin dilaurate) or 1,8-diazabicyclo[5.4.0]undec-7-ene. In comparison, phosphonic a...

2012
Guillermo H. Jimenez-Aleman Tim Schöner Ana L. Montero-Alejo Wolfgang Brandt Wilhelm Boland

A convenient synthesis of (6R,7S)-(+)-himachala-9,11-diene, the pheromone of the chrysomelid beetle Phyllotreta striolata is described. The diene is obtained in a single operation by a spontaneous “bromination/dehydrobromination” of 2,6,6,9-tetramethylbicyclo[5.4.0]undec-8-ene. The halogenation/dehalogenation sequence proceeds spontaneously in CCl4, and is less uniform in CH2Cl2 and CHCl3. H NM...

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