CsF–Celite as an efficient heterogeneous catalyst for sulfonylation and desulfonylation of heteroatoms
摘要:
CsF-Celite is found to be as an efficient reusable catalyst for sulfonylation and desulfonylation of heteroatoms. Sulfonamides and N-acylsulfonamides deprotect efficiently in the presence of CsF-Celite under solvent free conditions to give the free amines or amides in good to excellent yields. (C) 2011 Elsevier B.V. All rights reserved.
A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10
−8
to 1×10
−6
mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.
The present invention is directed to particles comprising 5-ALA esters salts, formulation thereof, related methods of preparation and methods of use thereof. In particular, the invention relates to particles comprising 5-ALA esters salts, formulation thereof useful in the treatment of a cancer and/or the diagnosis of a cancer cell such as in photodynamic therapy or photodynamic diagnosis.
Reaction of Lithium Diethylamide with an Alkyl Bromide and Alkyl Benzenesulfonate: Origins of Alkylation, Elimination, and Sulfonation
作者:Lekha Gupta、Antonio Ramírez、David B. Collum
DOI:10.1021/jo101505x
日期:2010.12.17
examine reactions of lithium diethylamide in tetrahydrofuran (THF) with n-dodecyl bromide and n-octyl benzenesulfonate. The alkyl bromide undergoes competitive SN2 substitution and E2 elimination in proportions independent of all concentrations except for a minor medium effect. Rate studies show that both reactions occur via trisolvated-monomer-based transition structures. The alkyl benzenesulfonate undergoes
结合使用 NMR、动力学和计算方法来检查二乙胺锂在四氢呋喃 (THF) 中与正十二烷基溴和正辛基苯磺酸盐的反应。烷基溴以与所有浓度无关的比例进行竞争性 S N 2 取代和 E2 消除,除了轻微的中等影响。速率研究表明,这两种反应都是通过基于三溶剂化单体的过渡结构发生的。烷基苯磺酸盐经历竞争性 S N 2 取代(次要)和 N-磺化(主要),在低 THF 浓度下促进 N-磺化。在S Ñ2 取代显示通过二溶剂化单体进行,计算表明涉及环状过渡结构。主要的 N-磺化遵循基于二溶剂化二聚体的过渡结构,计算表明为双环 [3.1.1] 形式。两个反应的不同 THF 和二乙胺锂顺序解释了观察到的浓度依赖性化学选择性。
Plastic lens
申请人:——
公开号:US20030055200A1
公开(公告)日:2003-03-20
A plastic lens, an optical molded article, a film or a sheet formed of a copolycarbonate resin comprising a structural unit (I) of the following general formula (I),
1
and a structural unit (II) of the following formula (II),
2
the structural unit (I) having a molar amount percentage of 15 to 85% on the basis of the total amount of the structural units (I) and (II).
According to the present invention, there are provided a plastic lens, an optical molded article, and the like, which are excellent in physical properties such as transparency, thermal stability and impact resistance and are excellent in optical properties such as a balance between a refractive index and an Abbe's number and a photoelasticity constant.
The object of this invention is to provide an optical film formed of a copolycarbonate having a desired chromatic dispersion and low photoelasticity and having excellent melt processability.
The optical film comprises a copolycarbonate composed of 25 to 90 mol % of unit (A) of the following formula,
wherein each of R
1
and R
2
is independently a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, each of R
3
and R
4
is independently a hydrocarbon group having 1 to 10 carbon atoms, each of m and n is independently an integer of 0 to 4, and each of p and q is independently an integer of 0 or more,
and 10 to 75 mol % of unit (B) of the following formula,
wherein R
a
is a monocyclic or polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms, the alicyclic hydrocarbon group may contain a hetero atom or may have a bridge structure, and q is 0 or 1,
the optical film satisfying the following expression (1),
R
(450)<
R
(550)<
R
(650) (1)
wherein R(450), R(550) and R(650) are in-plane retardation values of the film at wavelengths of 450 nm, 550 nm and 650 nm.