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 Morehangzhou verychem science and technology co.ltd
website:http://www.verypharm.com
Contact:+86-571-88162785; 88162786
Address:F1502, 753 Shenhua road, Hangzhou, China
Hangzhou Share Chemical Co., Ltd(expird)
Contact:+86-57187093700
Address:Hang Xing Road
Contact:86 21 3772 9386
Address:Rm.1803,Starry Bldg.1,1505 Meijiabang Road,Shanghai 201620 China
Contact:0833-5590788/5590338/5590055
Address:Victory in the town of Red Star Village,Mount Emei City,industrial concentration area storage processing logistics parkpark
VanderArk International Limited
Contact:86-10-82437576
Address:Qing He
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)
