Theoretical and experimental study on the reactivity of methyl dichlorobenzoates with sulfur-centered nucleophiles by electron transfer reactions

New Synthesis and Biological Evaluation of Benzothiazole Derivates as Antifungal Agents

“…17 Aryldihalides and phenyl thiolate afforded monosubstitution with retention of halide, monosubstitution with loss of halide, or disubstitution products, depending on relative reactivity of halides. 18 2-Mercaptobenzothiazole-2-benzylsulfanyl derivatives were synthesized in 94−98% yields by reaction between 2mercaptobenzothiazole and benzyl bromides in refluxing acetone in the presence of K 2 CO 3 . Synthesized compounds were found to be either weakly active or inactive against Escherichia coli, Candida albicans, etc.…”

“…It is well-known that aryl halides can afford substitution products with different aryl thiolates at good yields by the unimolecular radical nucleophilic substitution (S RN 1) mechanism . Aryldihalides and phenyl thiolate afforded monosubstitution with retention of halide, monosubstitution with loss of halide, or disubstitution products, depending on relative reactivity of halides …”

Cobalt-Catalyzed Methoxycarbonylation of Substituted Dichlorobenzenes as an Example of a Facile Radical Anion Nucleophilic Substitution in Chloroarenes

“…The authors explained positive ortho -effect of the acetyl group on the fragmentation rate of haloacetophenone in terms of π* and σ* orbital isomeric radical anions, their energy difference and the probability of an intramolecular electron-transfer reaction from the π* to the σ* system. Santiago and coworkers [44,45] came to the same conclusions about the impact of a methoxycarbonyl group, performing calculations for substituted methyl benzoates. However, it should be noted that the main geometric, thermodynamic and kinetic parameters of radicals and radical anion intermediates were determined in gas phase.…”

“…Positive ortho- effects in the radical anion substitution reactions have been observed previously by several researchers but only for substituents that have the mesomeric acceptor effect [40,41,42,43,44,45]. For example, there is a positive ortho -effect of the acetyl group for radical anion reactions of 2- and 4-chloroacetophenone, manifested in greater dehalogenation rate of 2-chloroacetophenone in comparison with 4-chloroacetophenone in irradiated aqueous solutions [40] and during the reduction with 1,3-dimethyl-2-phenylbenzimidazoline [41].…”

“…For example, there is a positive ortho -effect of the acetyl group for radical anion reactions of 2- and 4-chloroacetophenone, manifested in greater dehalogenation rate of 2-chloroacetophenone in comparison with 4-chloroacetophenone in irradiated aqueous solutions [40] and during the reduction with 1,3-dimethyl-2-phenylbenzimidazoline [41]. A similar accelerating effect is demonstrated by о- CN [42] and о- COPh [41] groups at dehalogenation and о- CO 2 Me group in reactions of methyl 2,5-dichlorobenzoate or methyl 3,6-dichloro-2-methoxybenzoate with tin-centred [43,44] and sulphur centred [45] nucleophiles.…”