Solvolysis of 1-Aryl-1-tert-butylmethyl Bromides. Hammett-Type Correlation Analysis and RevisedYBnBrScale
摘要:
AbstractThe solvolysis of a series of 1‐aryl‐1‐tert‐butylmethyl bromides (1a–1g) in a variety of solvents were carried out. Linear relationships were observed from Hammett‐type analysis of logarithm of rate constants using single‐parameter Brown‐Okamoto equation (Eqn. 1) and dual‐parameter Yukawa‐Tsuno equation (Eqn. 2), respectively. The ρ values and the γ values were found to depend mainly on the range of substituents and not the type of solvents employed. The observation of an upward deviation for the data points of strongly deactivating substrates 1f and 1g could be interpreted by an electrophilic acceleration owing to the solvation of leaving group. It is likely an additional example of overshadowed solvent effect in the dual‐parameter treatment of rate data. Moreover, the variation of γ values was found contradicting the general consideration of resonance contribution. The observed excellent linear correlations with YBnBr and the good solubility in aqueous solution with high percentage of water made 1c a better reference standard than 2‐bromo‐2‐(4‐trifluormethyl)adamantane (3) for obtaining revised and extended YBnBr values. Correlation analysis using the single‐parameter Grunwald‐Winstein equation (Eqn. 3) with YBnBr was found to be superior over the dual‐parameter equation containing YBr and I (Eqn. 5).
SUBSTITUTED ARYLCYCLOPENTENES AS THERAPEUTIC AGENTS
申请人:Donde Yariv
公开号:US20090270387A1
公开(公告)日:2009-10-29
Compounds comprising
or a pharmaceutically acceptable salt or a prodrug thereof, are disclosed, wherein Y, A, and B are as described.
Methods, compositions, and medicaments related thereto are also disclosed.
包含Y、A和B的化合物或其药用盐或前药的方法、组合物和药物也被揭示。
THERAPEUTIC SUBSTITUTED HYDANTOINS, AND RELATED COMPOUNDS
申请人:Old David W.
公开号:US20090281101A1
公开(公告)日:2009-11-12
Compounds comprising a structure
or a pharmaceutically acceptable salt thereof, or a prodrug thereof;
wherein a dashed line represents the presence or absence of a bond are disclosed,
wherein Y, A, B, and J are as described.
Methods, compositions, and medicaments related thereto are also disclosed.
We have investigated the reductive cleavage of arylalkyl methylethers with an excess of lithium metal and a catalytic amount of naphthalene. The reaction proceeds regioselectively in the presence of various substituents on the aromatic ring, allowing access to a wide array of arylalkyl lithium derivatives, some of which are not easily accessible by conventional methods.
Electronictuning: Nitroxylradical 1 is shown to be an efficient catalyst for the oxidation of secondary alcohols, and promotes oxidation through an oxoammonium species which is highly reactive because of the adjacent electron‐withdrawing ester groups. Chemoselectiveoxidation of benzylic alcohols in the presence of aliphatic alcohols is observed and is proposed to proceed by a rate‐determining hydride
Bi-aryl rotation in phenyl-dihydroimidazoquinoline catalysts for kinetic resolution of arylalkyl carbinols
作者:Zheng Wang、Jinjin Ye、Rui Wu、Yang-Zi Liu、John S. Fossey、Jiagao Cheng、Wei-Ping Deng
DOI:10.1039/c3cy00904a
日期:——
Chiral nucleophilic catalysts, 6-aryl-phenyl-dihydroimidazoquinolines (PIQs), were designed, synthesised and applied to the kineticresolution of arylalkyl carbinols with very high selectivity (S) factors (up to 530). Density functional theory calculations indicate that multiple noncovalent interactions play a key role in chiralrecognition between 6-aryl-PIQ catalysts and chiral secondary alcohol