نتایج جستجو برای: polyolfine cyclic compound

تعداد نتایج: 223829  

2011
Xia Gui Zhigang Tang Weiyang Fei

The solubility of CO2 in ester mixtures under high pressures are studied in this article. The constant-volume method is used to determine the solubility of CO2 in DMC + diethyl carbonate system, DMC + propyl acetate system, DMC + propylene carbonate system, and DMC + ethylene carbonate system from 282.0 K to 303.0 K. It is found that the solubility of CO2 in four mixed solvents follows the Henr...

2018
Yang Zong Liting Yang Shanyu Tang Longjia Li Wanjie Wang Bingxin Yuan Guanyu Yang

An efficient catalytic system was developed for the acetalization and ketalization of carbonyl compounds with polyhydric alcohols under mild solvent-free conditions. In the presence of 0.1 mol% CoCl2 and 0.2 mol% dimethylglyoxime at 70 ◦C under 5 KPa pressure for 1 h, 95.3% conversion of cyclohexanone and 100% selectivity of the corresponding cyclic ketal could be obtained, where TOF reached as...

Journal: :Chemphyschem : a European journal of chemical physics and physical chemistry 2006
Claudio Carra Rafael Nussbaum Thomas Bally

2,6-Difluorophenylnitrene was reinvestigated both experimentally, in Ar matrices at 10 K, and computationally, by DFT and CASSCF/CASPT2 calculations. Almost-pure samples of both neutral rearrangement products (the bicyclic azirine and the cyclic ketenimine) of a phenylnitrene were prepared and characterized for the first time. These samples were then subjected to X-irradiation in the presence o...

2008
Rana Shabnam Habib Muhammad Jamshaid M. Nawaz Tahir Tahir Javed Khan Islam Ullah Khan

The title compound, C(20)H(26)O(4), was extracted from Leucas Urticifolia, a wild Lamiaceae herb distributed in the Punjab, Baluchistan, Sindh and the Rajputana desert of Pakistan. The plant is utilized for various medicinal applications by the local community. The title compound is based on the pimarane-diterpene skeleton. The mol-ecule exhibits an ep-oxy ring fused to momilactone-A, leading t...

2008
In-Chul Hwang Kwang Ha

The asymmetric unit of the title compound, [Mn(C(2)H(3)O(2))(2)(C(18)H(20)N(4))]·6H(2)O, consists of a neutral Mn(II) complex with six solvent water mol-ecules. In the complex, the Mn(2+) ion is eight-coordinated in a distorted square-anti-prismatic environment by four N atoms from the tetra-dentate ligand N,N'-bis-(2-pyridylmethyl-idene)cyclo-hexane-1,2-diamine (bpic) and four O atoms from two...

Journal: :Genome informatics. Workshop on Genome Informatics 1999
Arita Asai Nishioka

A precursor is a compound which is transformed to a class of functional molecules within short steps. It is an important process in the production of natural drugs to decide whether a given compound is a precursor or not. We present two strategies to select precursor compounds in the secondary metabolism of terpenoids: one is to find the packing of basic molecules in the given cyclic structure,...

2017
Joana M Pais Maria João Barroca Maria Paula M Marques Filipe A Almeida Paz Susana S Braga

Fisetin is a natural antioxidant with a wide range of nutraceutical properties, including antidiabetic, neuroprotecting, and suppression or prevention of tumors. The present work describes the preparation of a water-soluble, solid inclusion compound of fisetin with gamma-cyclodextrin (γ-CD), a cyclic oligosaccharide approved for human consumption. A detailed physicochemical analysis of the prod...

Journal: :Organic & biomolecular chemistry 2009
Michael Merschky Carsten Schmuck

Kinetic studies of a low-molecular weight organocatalyst 1 are presented. Compound 1 contains two histidines and one cationic side chain attached to a central aromatic core. In aqueous solution 1 accelerates the hydrolysis of a prototypal phosphodiester with rate enhancements of up to two orders of magnitude. A detailed HPLC analysis of hydrolysis experiments in Bis-Tris-buffer showed that the ...

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