Conformational Analysis of Spiro-bis-dithiepins: A Peculiar Case of Axial Chirality
摘要:
Spiro-bis-dithiepins are synthesized via dehydrative ring expansion in alpha-hydroxyalkyl spiro-bis-dithianes. Atypical of spiranes possessing axial chirality, the two most stable conformers of substituted spiro-bis-dithiepin have virtually colinear double bonds; i.e., each enantiomer exists in a form of two energy degenerate syn and anti conformations. Because of the high polarizability of the vinyl sulfide moiety, spiro-bis-dithiepins bearing electron-withdrawing substituents offer access to two-state systems possessing large dipole moments, which can be modulated by conformational events.
HIGH-FLUIDITY POLYCARBONATE COPOLYMER, PROCESS FOR PRODUCTION HIGHLY POLYMERIZED AROMATIC POLYCARBONATE RESIN AND AROMATIC POLYCARBONATE COMPOUND (AS AMENDED)
申请人:Isahaya Yoshinori
公开号:US20140206826A1
公开(公告)日:2014-07-24
The present inventions provide a novel polycarbonate copolymer having high fluidity and high molecular weight which is formed of a structural unit derived from an aliphatic diol compound and a structural unit derived from an aromatic dihydroxy compound, having a structure represented by the formula (III):
having the content of the structural unit derived from the aliphatic diol compound of 1-30 mol %, having the Q-value (280° C., 160 kg load) in the range from 0.02 to 1.0 ml/s, and having the weight average molecular weight (Mw) of 30,000 to 100,000, and an aromatic polycarbonate compound which is formed of a structural unit derived from an aromatic dihydroxy compound which is suitable for a prepolymer for producing a high fluidity polycarbonate copolymer
HIGH-FLUIDITY POLYCARBONATE COPOLYMER, PROCESS FOR PRODUCTION HIGHLY POLYMERIZED AROMATIC POLYCARBONATE RESIN AND AROMATIC POLYCARBONATE COMPOUND
申请人:MITSUBISHI GAS CHEMICAL COMPANY, INC.
公开号:US20160264726A1
公开(公告)日:2016-09-15
The present inventions provide a novel polycarbonate copolymer having high fluidity and high molecular weight which is formed of a structural unit derived from an aliphatic diol compound and a structural unit derived from an aromatic dihydroxy compound, having a structure represented by the formula (III):
having the content of the structural unit derived from the aliphatic diol compound of 1-30 mol %, having the Q-value (280° C., 160 kg load) in the range from 0.02 to 1.0 ml/s, and having the weight average molecular weight (Mw) of 30,000 to 100,000, and an aromatic polycarbonate compound which is formed of a structural unit derived from an aromatic dihydroxy compound which is suitable for a prepolymer for producing a high fluidity polycarbonate copolymer.
US9353216B2
申请人:——
公开号:US9353216B2
公开(公告)日:2016-05-31
Conformational Analysis of Spiro-bis-dithiepins: A Peculiar Case of Axial Chirality
作者:Edmir O. Wade、Roman A. Valiulin、Leslie A. Ruybal、Andrei G. Kutateladze
DOI:10.1021/ol062172s
日期:2006.10.1
Spiro-bis-dithiepins are synthesized via dehydrative ring expansion in alpha-hydroxyalkyl spiro-bis-dithianes. Atypical of spiranes possessing axial chirality, the two most stable conformers of substituted spiro-bis-dithiepin have virtually colinear double bonds; i.e., each enantiomer exists in a form of two energy degenerate syn and anti conformations. Because of the high polarizability of the vinyl sulfide moiety, spiro-bis-dithiepins bearing electron-withdrawing substituents offer access to two-state systems possessing large dipole moments, which can be modulated by conformational events.
Backer; Evenhuis, Recueil des Travaux Chimiques des Pays-Bas, 1937, vol. 56, p. 681,688