The influence of heteroatoms on the conformational properties of heteracalix[4]arenes. Comparison of oxygen-, sulfur-, and nitrogen-bridged [14]metacyclophanes
摘要:
Oxygen- and sulfur-bridged calix[4]arenes have been synthesized by the nucleophilic aromatic substitution of 1,5-difluoro-2,4-dinitrobenzene with 4,6-diisopropylresorcinol or 4,6-diisopropyl-1,3-benzene-dithiol. X-ray crystal structure analyses revealed that the oxacalix[4]arene 2 adopts an unsymmetrical 1,3-alternate Conformation and that the dinitrobenzene rings strongly conjugate with the bridging oxy, en atoms. On the other hand, the thiacalix[4]arene 3 adopts a heavily twisted unsymmetrical 1,3-alternate conformation, and the conjugation is very weak. In the H-1 NMR spectrum (CDCl3, 30 degrees C) both compounds display a pair of diastereotopic methyl signals for the isopropyl groups in agreement with the frozen 1,3-alternate conformation on the NMR time scale. The free energies of activation (Delta G(298)(#)) of the macrocyclic inversion for 2 and 3 were determined to be 69.5 kJ mol (1) and 74.9 kJ mol(-1), respectively, by variable temperature NMR spectroscopy. (C) 2009 Elsevier Ltd. All rights reserved.
MODIFIER FOR AROMATIC POLYESTER AND AROMATIC POLYESTER RESIN COMPOSITION COMPRISING THE SAME
申请人:TABATA Masayoshi
公开号:US20110224343A1
公开(公告)日:2011-09-15
The present invention provides a modifier for aromatic polyesters which enhances the melt fluidity of aromatic polyesters without a significant decrease in the heat resistance of the aromatic polyesters, and an aromatic polyester resin composition including the modifier for aromatic polyesters. The present invention relates to a modifier for aromatic polyesters comprising polyhydric phenol residues and residues of aromatic polycarboxylic acid, acid halide or acid anhydride thereof, and the modifier comprises a material having a structure composed of a first residue selected from the group consisting of divalent residues represented by Formula (I): —Ar—W
1
x
—Ar— and by Formula (II): —Ar—, the first residues being bonded to two identical or different second residues selected from the group consisting of monovalent residues represented by Formula (III):
and monovalent residues represented by Formula (IV): —O—C(O)—R
7
—.
This invention relates to a new class of polyhydric phenol carbonate esters and to synthetic resin stabilizer compositions comprising these esters as well as to synthetic resins stabilized with such esters and with stabilizer compositions comprising these esters along with known polymer stabilizers.
[EN] PROCESS FOR THE PREPARATION OF A COSMETIC ACTIVE<br/>[FR] PROCEDE POUR PREPARER UNE SUBSTANCE COSMETIQUE ACTIVE
申请人:UNILEVER PLC
公开号:WO2004052814A1
公开(公告)日:2004-06-24
A process for the preparation of one or more compounds of formula (I), wherein R1 is hydrogen or iso-alkyl and R2 is an iso-alkyl group; comprising the single step of reacting resorcinol with at least one secondary alcohol in the presence of a proton donor acid catalyst wherein the reaction is carried out in a water removing system.
Benzoic Acid Derivatives that are Modulators or Agonists of GlyR
申请人:Gyback Helena
公开号:US20090192190A1
公开(公告)日:2009-07-30
Compounds of formula I,
wherein R1, Z, Y, M and R2 are as defined in the specification, pharmaceutically acceptable salts thereof, pharmaceutical composition containing the same, methods of using the same for therapeutic purposes and methods of making the same.
The present invention provides an aromatic polyester which is substantially free from the occurrence of coloration and retains significantly high transparency even after being thermally processed at high temperature and which has high flowability. The aromatic polyester contains a polyhydric phenol residue and a residue of any one of aromatic polycarboxylic acid, halide thereof, and anhydride thereof, and terminals of the aromatic polyester have a structure represented by the formula -C(O)-R. The aromatic polyester has an end-capping rate of 90% or higher and a weight average molecular weight (Mw) ranging from 3,000 to 1,000,000.