Journal of the Chemical Society. Perkin transactions II p. 1117 - 1120 (1986)
Update date:2022-08-03
Topics:
Pruszynski, Przemyslaw
Jarczewski, Arnold
Kinetic studies have been carried out on the proton-transfer reactions of (i) 4-nitrobenzyl cyanide (4-NBC) with tetramethylguanidine (TMG) and (ii) 4-nitrophenylphenylcyanomethane (4-NPPCM) with 1,8-bis(dimethylamino)naphthalene (DMAN) in acetonitrile.The reaction (i) has a moderate enthalpy of activation (ΔH++ = 25 kJmol-1) and a negative entropy of activation (ΔS++ = -98 Jmol-1K-1).The deuterium kinetic isotope effect is large.The reaction (ii) of the more hindered molecule 4-NPPCM and DMAN has similar activation parameters (ΔH++ = 26 kJmol-1, ΔS++ = -140 Jmol-1K-1), but the kinetic isotope effect is considerably larger; also ΔHD++ - ΔHH++ is larger (13 kJmol-1) and AH/AD is small, indicating a considerable tunnelling effect.Evidence that the larger isotope effect are not artefacts of hydrogen exchange is presented.The tunnelling factor is estimated.
View Morewebsite:http://www.apeptides.com/en/
Contact:+86-21-60871011
Address:No. 80 Chuanshan Shuyuan Steet,Pudong,Shanghai
ShanDong XinDa Chemical CO.,LTD(expird)
Contact:086-0311-87580543
Address:No.168, High Technology Development Zone Jinan Shandong China
website:http://www.truewingroup.com
Contact:86-311-66699812
Address:NO.600 ZHONGSHAN EAST ROAD SHIJIAZHUANG
Shanghai birch chemical technology co.,ltd
Contact:+86-21-54096810
Address:No.2588,Jungong Road,Shanghai,China
Jiande City Silibase Silicone New Material Manufacture Co., Ltd.
Contact:15967177856
Address:Genglou Industrial Development Area
Doi:10.1002/cplu.201402072
(2014)Doi:10.1016/j.ejmech.2009.06.029
(2009)Doi:10.1021/jo060334s
(2006)Doi:10.1039/b605278a
(2006)Doi:10.1016/j.tetlet.2006.04.132
(2006)Doi:10.1016/j.bmcl.2007.10.055
(2007)
