45951-91-5

Upstream product

• 66735-55-5 phenyl methyl sulfate 
• 108-95-2 phenol 

Relevant academic research and scientific papers

Reactivity-Selectivity Correlations. 4. The α Effect in SN2 Reactions at sp3 Carbon. The Reactions of Hydrogen Peroxide Anion with Methyl Phenyl Sufates

A kinetic study is reported of the reactions of substituted phenyl methyl sulfates with hydrogen peroxide and methoxide ion in methanol solvent at 25 deg C.Dissection of the rate data for the H2O2/MeONa system allows the specific coefficients kHOO- and kMeO- to be evaluated.Hydroperoxide anion is found to be more reactive than methoxide ion (kHOO-/kMeO- varies from 6 to 11 depending on the sustrate), indicating than an α effect is operating for this nucleophilic attack at saturated carbon.This is in agreement with earlier results on the enhanced reactivity of hydrazine relative to glycine ethyl ester.The results further show that the Hammett p value for the α nucleophiles is smaller than for the normal nucleophiles; however an inverse order is found for the respective Bronsted β values.Analysis of these contrasting relationships in terms of reaction coordinate diagrams leads to the conclusion that the ordinary two-dimensional reaction coordinate is not applicable to the α nucleophiles and that significant anti-Hammond effects arise in these cases.The shift in the transition state perpendicular to the diagonal is discussed in terms of destabilization of the α nucleophile or via a tight transition-state structure as previously suggested for transmethylation.It is concluded that the Hammett p value is a valid criterion of the reactivity-selectivity principle (RSP) for the normal nucleophiles which conform to the two-dimensional representation but not for the α nucleophiles.This leads to a limitation on the applicability of the RCP as a measure of transition-state structure.

A new arylsulfate sulfotransferase involved in liponucleoside antibiotic biosynthesis in streptomycetes

Sulfotransferases are involved in a variety of physiological processes and typically use 3′-phosphoadenosine 5′-phosphosulfate (PAPS) as the sulfate donor substrate. In contrast, microbial arylsulfate sulfotransferases (ASSTs) are PAPS-independent and utilize arylsulfates as sulfate donors. Yet, their genuine acceptor substrates are unknown. In this study we demonstrate that Cpz4 from Streptomyces sp. MK730-62F2 is an ASST-type sulfotransferase responsible for the formation of sulfated liponucleoside antibiotics. Gene deletion mutants showed that cpz4 is required for the production of sulfated caprazamycin derivatives. Cloning, overproduction, and purification of Cpz4 resulted in a 58-kDa soluble protein. The enzyme catalyzed the transfer of a sulfate group from p-nitrophenol sulfate (Km 48.1 μM, k cat 0.14 s-1) and methyl umbelliferone sulfate (K m 34.5 μM, kcat 0.15 s-1) onto phenol (Km 25.9 and 29.7 mM, respectively). The Cpz4 reaction proceeds by a ping pong bi-bi mechanism. Several structural analogs of intermediates of the caprazamycin biosynthetic pathway were synthesized and tested as substrates of Cpz4. Des-N-methyl-acyl-caprazol was converted with highest efficiency 100 times faster than phenol. The fatty acyl side chain and the uridyl moiety seem to be important for substrate recognition by Cpz4. Liponucleosides, partially purified from various mutant strains, were readily sulfated by Cpz4 using p-nitrophenol sulfate. No product formation could be observed with PAPS as the donor substrate. Sequence homology of Cpz4 to the previously examined ASSTs is low. However, numerous orthologs are encoded in microbial genomes and represent interesting subjects for future investigations.