ABSTRACT
A facile method for the synthesis of 4-chalcogenylated pyrazoles has been developed via electrophilic chalcogenation/cyclization of α,ß-alkynic hydrazones. The cyclization of α,ß-alkynic aldehyde hydrazones could be induced by using either sulfenyl chloride or the S-electrophiles generated in situ from the reaction of NCS and arythiol. The developed method was successfully applied to the synthesis of the sulfenyl analogue of celecoxib.
ABSTRACT
Disulfide bonds are a significant motif in life and drug-delivery systems. In particular, steric hindrance and stereoscopic disulfide linkers are closely associated with the stability of antibody-drug conjugates, which affects the potency, selectivity, and pharmacokinetics of drugs. However, limited availability and diversity of tertiary thiols impede the construction of steric and stereoscopic disulfides for cross-linkage in biochemistry and pharmaceuticals. Through modulating the mask effect of disulfurating reagents, we develop a facile and robust strategy for construction of diverse steric and stereoscopic disulfides via N-dithiophthalimides. The practical cross-linkage of biomolecules including amino acids, saccharides, and nucleosides with different drugs and fluorescent molecules is successfully established through hindered disulfide linkers.
ABSTRACT
A new kind of electrophilic alkynylthiolating reagent, called N-alkynylthio phthalimide, is designed and synthesized herein. This electrophilic sulfenylating reagent can be easily prepared in three steps from commercially available phthalimide and corresponding silver acetylide. Furthermore, the N-alkynylthio phthalimides are demonstrated to be efficient alkynylthio transfer reagents that can react with various C-nucleophiles, including ß-ketoesters, aryl boronic acids, and Grignard reagents to afford a diverse range of alkynyl thioethers under mild conditions.
ABSTRACT
A new and convenient method for one-pot synthesis of α-arylhydrazo-ß-keto sulfones is developed via Cu (II)-catalyzed oxysulfonylation/diazenylation of alkenes. This four-component cascade reaction enables a series of α-arylhydrazo-ß-keto sulfone derivatives accessed from readily available alkenes, sulfinates, and diazonium salts under aerobic conditions. Furthermore, the 3-sulfonyl cinnolin-4(1 H)-one skeleton is successfully constructed from the corresponding α-arylhydrazo-ß-keto sulfone product under basic conditions.