Diaryl sulfide cleavage by sodium sulfide in dipolar aprotic solvents

Abstract

The cycloaddition of various types of a./J-unsaturated imines with diphenyl-and dichloroketenes yields both (2 + 2) and (4 + 2) cycloaddition products, i.e., /3-lactams and -lactams, respectively. The cycloaddition products are dependent upon substitution in the imine and the ketene. The -lactams derived from dichloroketene are easily dehydrochlorinated to the corresponding 2-pyridones. All of the results are consistent with a two-step cycloaddition process involving a dipolar intermediate.

Bis(2,4-dinitrophenyl)sulfane

“…For applications of bis(2,4-dinitrophenyl)sulfane, see: Nakadate et al (1964); Alekhina et al (1978); Parihar et al (1971); Evans & Kinnard (1983); Andricopulo et al (2006). For related syntheses, see: Pesin et al (1963); Joshi & Mathur (1963); Obata et al (1966); Stepanov et al (1974); Davydov & Beletskaya (2003).…”

“…The title sulfur containing organic compound is a biologically active molecule (Andricopulo et al, 2006). It has been utilized in many clinical trials (Nakadate et al, 1964;Alekhina et al, 1978) and also employed in the synthesis of a number of other important organic molecules (Parihar et al, 1971;Evans & Kinnard, 1983). Several methods have been reported for the synthesis of the title molecule (Pesin et al, 1963;Joshi & Mathur, 1963;Obata et al, 1966;Stepanov et al, 1974;Davydov & Beletskaya, 2003).…”

Poly(arylene sulfide)s via nucleophilic aromatic substitution reactions of halogenated pyromellitic diimides

“…Swager et al 13 went further to exploit the pseudo‐degenerate ipso ‐substitution 15 of thiolate leaving groups with other thiolates to depolymerize PAS's with small‐molecule thiols as chain limiters and using only a catalytic amount DBU as base at room temperature! This facile reaction under mild conditions with PASs carrying activating electron‐withdrawing groups stands in stark contrast to the cleavage of unactivated and weakly activated diaryl sulfides requiring substantially more forcing conditions (e.g., ≥120°C) 16 . We show here that PMDI‐X2 species react rapidly and in quantitative conversion with thiolates at room temperature, including both small‐molecule model studies and step (condensation) polymerizations.…”

Aromatic Polyazines by a Copper‐Amine Catalyzed Oxidative Polymerization Reaction

“…]-undecene-7, (DBU), benzophenoneimine, aminodiphenylmethane, 1,4-dicyanobenzene, benzoyl chloride, diphenyl ether, all from Aldrich, were used as received or as otherwise stated. Benzophenone hydrazone, [23,24] 4,4 0 -oxybis(benzonitrile) (1b) [25] bis(4-cyanophenyl)sulfide [26] (1c), 1,1 0 -bis(4-benzoylphenyl)ether [27] (4a), 4,4 0 -dibenzoyldiphenyl ether dihydrazone [28] (4b) were synthesized as reported in the literature. Phenyllithium was prepared from bromobenzene as described [29] and used as the ether solution.…”