International Journal of Chemical Kinetics p. 477 - 488 (2014)
Update date:2022-08-03
Topics:
Asghar, Basim H.
The feasibility of carrying out nucleophilic addition from electron-deficient heteroaromatics has been addressed through a detailed investigation of the interaction of a two 7-substituted-nitrobenzofurazan (R = OMe 2a; R = Cl 2b) with a series of substituted-nitroaryl anions (X = 4-NO 2 1a; X = 3-NO2 1b; X = 4-CN 1c; X = 4-Br 1d), all reactions first lead to the quantitative formation of the σ-adducts 3a-d and 4a-d arising from covalent addition of the nucleophile to the C-5 carbon. The rate and equilibrium constants for the formation of σ-adducts 3a-d and 4a-d (k5, K5) together with the rate constants for their decomposition (k-5) have been determined in methanol at 25C, allowing a determination of intrinsic rate constants, k0 = 0.03, the lower k0 value reflects the very strong salvation by methanol of the negative charge on the nitro group. The discovery of a linear correlation between the E and pKaMeOH parameters allows a calibration of the electrophilicity power of 2a and 2b, E = -11.67 and -10.29, respectively. Applying the general approach to nucleophilicity/electrophilicity recently developed by Mayr et al. through the relationship log k = s(E + N), a successful ranking of our nitroaryl anions 1a-d on the general nucleophilicity scale (N) has been carried out. The N values of 1a-d are found to cover a range from 15.78 to 16.69. The results are compared with previously reported data in water and DMSO.
View Morewebsite:http://www.hope-chem.com
Contact:86-21-58090396-805
Address:Floor 4, Building 5, No.588 Tianxiong Road, Zhoupu International Medical Zone, ShangHai, China
KAIYUAN CHEMICAL COMPANY LIMITED.
website:http://www.kaiyuanchem.com
Contact:+86-22-59891255/66/77
Address:B-2205, Kuangshi International Building, Yingbin Road, XiangLuo Bay Business District, Binhai New area, Tianjin, China.
website:http://www.herbpurify.com
Contact:0086-028-85249238
Address:Room709-C1,Incubator Building, Tianfu Life Science Park No.88,Keyuan Road,Gaoxin district,Chengdu City,Sichuan Prov,China
Tianjin Dongchang Fine Chemical Industry Co., Ltd.
Contact:+86-22-29894595
Address:Economic Developing Zone, Ji County, Tianjin, China
Contact:--
Address:80G, No.1 Building, Guodu Development Mansion, No. 182 Zhaohui Road, Hangzhou City, Zhejiang Province,China.
Doi:10.1248/cpb.44.871
(1996)Doi:10.1021/ja01630a100
(1954)Doi:10.1021/ja01549a070
(1958)Doi:10.1246/bcsj.44.2271
(1971)Doi:10.1002/ardp.200400869
(2004)Doi:10.1080/10426500214568
(2002)