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Upstream product

• 111-27-3 hexan-1-ol 
• 98-74-8 4-Nitrobenzenesulfonyl chloride 

Relevant academic research and scientific papers

Inscribing the perimeter of the PagP hydrocarbon ruler by site-specific chemical alkylation

The Escherichia coli outer membrane phospholipid:lipid A palmitoyltransferase PagP selects palmitate chains using its β-barrel-interior hydrocarbon ruler and interrogates phospholipid donors by gating them laterally through an aperture known as the crenel. Lipid A palmitoylation provides antimicrobial peptide resistance and modulates inflammation signaled through the host TLR4/MD2 pathway. Gly88 substitutions can raise the PagP hydrocarbon ruler floor to correspondingly shorten the selected acyl chain. To explore the limits of hydrocarbon ruler acyl chain selectivity, we have modified the single Gly88Cys sulfhydryl group with linear alkyl units and identified C10 as the shortest acyl chain to be efficiently utilized. Gly88Cys-S-ethyl, S-n-propyl, and S-n-butyl PagP were all highly specific for C12, C11, and C10 acyl chains, respectively, and longer aliphatic or aminoalkyl substitutions could not extend acyl chain selectivity any further. The donor chain length limit of C10 coincides with the phosphatidylcholine transition from displaying bilayer to micellar properties in water, but the detergent inhibitor lauryldimethylamine N-oxide also gradually became ineffective in a micellar assay as the selected acyl chains were shortened to C10. The Gly88Cys-S-ethyl and norleucine substitutions exhibited superior C12 acyl chain specificity compared to that of Gly88Met PagP, thus revealing detection by the hydrocarbon ruler of the Met side chain tolerance for terminal methyl group gauche conformers. Although norleucine substitution was benign, selenomethionine substitution at Met72 was highly destabilizing to PagP. Within the hydrophobic and van der Waals-contacted environment of the PagP hydrocarbon ruler, side chain flexibility, combined with localized thioether-aromatic dispersion attraction, likely influences the specificity of acyl chain selection.

Photooxidation of alkyl 4-nitrophenyl sulfides and sulfoxides. Observation of oxidative C-S bond cleavage and rearrangement reactions

Alkyl 4-nitrophenyl sulfides and sulfoxides undergo a self-photoinduced, singlet oxygen oxidation to produce a variety of products, including sulfonates and carbonyl compounds formed by the oxidative cleavage of the C-S bond of the sulfides and sulfoxides. Structural rearrangements are observed in the resulting carbonyl compounds formed in the oxidative cleavage of the C-S bond in the tert-amyl and 2-phenylethyl sulfides. An overall mechanism is proposed which involves the formation of peroxysulfoxides and peroxysulfones which undergo heterolytic C-S bond cleavage to form ion pairs which recombine to form persulfenates or persulfinates which then undergo photo- and/or thermallyinduced homolytic O-O bond cleavage to form alkoxy and sulfinyl or sulfonyl radicals. The alkoxy radicals undergo β-scission, disproportionation, or recombination with the sulfonyl radical to form the observed products. These C-S oxidative cleavage reactions have only been rarely observed in the earlier studies on the singlet oxygen oxidation studies of dialkyl sulfides, and are attributed, in part, to the presence of the 4-nitro group on the aromatic ring which greatly affects the susceptibility of the sulfur atom of the sulfides and sulfoxides toward nucleophilic attack, and on the reactivity of the peroxysulfoxides and peroxysulfones toward heterolytic cleavage of the O-S bond.