Open AccessSelenium and Sulfur in Exchange Reactions: A Comparative Study
Author(s) -
Daniel Steinmann,
Thomas Nauser,
Willem H. Koppenol
Publication year - 2010
Publication title -
journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.2
H-Index - 228
eISSN - 1520-6904
pISSN - 0022-3263
DOI - 10.1021/jo1011569
Subject(s) - cystamine , selenium , cysteamine , nucleophile , chemistry , electrophile , sulfur , reaction rate constant , medicinal chemistry , computational chemistry , organic chemistry , kinetics , catalysis , biochemistry , physics , quantum mechanics
Cysteamine reduces selenocystamine to form hemiselenocystamine and then cystamine. The rate constants are k(1) = 1.3 × 10(5) M(-1) s(-1); k(-1) = 2.6 × 10(7) M(-1) s(-1); k(2) = 11 M(-1) s(-1); and k(-2) = 1.4 × 10(3) M(-1) s(-1), respectively. Rate constants for reactions of cysteine/selenocystine are similar. Reaction rates of selenium as a nucleophile and as an electrophile are 2-3 and 4 orders of magnitude higher, respectively, than those of sulfur. Sulfides and selenides are comparable as leaving groups.