98-48-6Relevant articles and documents
Biosynthesis of phloroglucinol
Achkar, Jihane,Xian, Mo,Zhao, Huimin,Frost
, p. 5332 - 5333 (2007/10/03)
Substantial concentrations of phloroglucinol were synthesized by Pseudomonas fluorescens Pf-5 expressing the plasmid-localized phlACBDE gene cluster responsible for biosynthesis of 2,4-diacetylphloroglucinol. Expression in Escherichia coli of a single gene in this cluster, P. fluorescens Pf-5 phlD, led to extracellular accumulation of phloroglucinol. Purification of PhlD to homogeneity afforded an enzyme that catalyzed the conversion of malonyl-CoA into phloroglucinol with Km = 5.6 μM and kcat = 10 min-1. Acetylase and deacetylase activities were observed with the catalyzed interconversions of phloroglucinol, 2-acetylphloroglucinol, and 2,4-diacetylphloroglucinol when phlACB was expressed in E. coli. Beyond the mechanistic implications attendant with the identification of an enzyme that catalyzes the conversion of malonyl-CoA into phloroglucinol, PhlD provides the basis for environmentally benign syntheses of phloroglucinol and resorcinol from glucose. Copyright
The positional reactivity order in the sulfur trioxide sulfonation of benzene and naphtalene derivatives containing an electron-withdrawing substituent
Cerfontain, Hans,Zou, Yousi,Bakker, Bert H.
, p. 403 - 410 (2007/10/02)
The reaction of sulfur trioxide with derivatives of benzene and naphthalene containing an electron-withdrawing substituent, viz.-SO3H, -SO2Ph, -NO2, -CHO, -COPh, -CO2H, and -CO2Me, in dichloromethane as solvent at ca. 22 deg C has been studied by analysis of the resulting mixtures of the sulfo derivatives with 1H-NMR.The initial sulfonation of the benzene derivatives yields the corresponding 3-sulfonic acid (3-S) and subsequently, with the exception of nitrobenzene and methyl benzoate, small amounts of 3,5-S2.Benzenesulfonic acid in addition undergoes sulfonylation giving 3,3'-di- and 3,5,3'-trisulfodiphenyl sulfone.Monosulfonation of naphtalene-1-S yields the 1,5-S2, 1,6-S2 and 1,7-S2 derivatives in a ratio of 71:20:9.On using a large excess of SO3, the eventual products are 1,3,5-S3, 1,3,6-S3 and 1,3,5,7-S4.Monosulfonation of naphthalene yields 5-S, 6-S, 7-S and 8-S in a 55:9:6:30 ratio, that of 1-benzoylnaphthalene 5-S, 6-S and 7-S in a ratio of 83:11:6, and 1-nitronaphtalene only the 5-S.The absence of peri sulfonation with 1-sulfo-, 1-benzoyl- and 1-nitronaphthalene is due to prohibitive steric hidrance. 1-Naphthoic acid and its methyl ester upon SO3 sulfonation and aqueous work-up both yield 5- and 8-sulfonaphthoic acid in a ratio of 65:35 and 77:21, respectively.The initially formed peri-substituted product is the intramolecular anhydride of 8-sulfo-1-naphthoic acid (5).All the 2-substituted naphthalenes yield 5-S and 8-S upon SO3 sulfonation of which the former sulfo isomer is far in excess.The positional reactivity orders for the SO3 sulfonation of the monosubstituted naphthalene derivatives are discussed in terms of the difference in reactivity of the α- and β-positions, and the steric and electronic effects of the deactivating substituent.
Reactions of SO2X mono-substituted arenes with SO3 in nitromethane: electronic and steric directing effects of the sulfonic acid group and some model substituents
Ansink, Harold R. W.,Graaf, Erik J. de,Zelvelder, Erwin,Cerfontain, Hans
, p. 210 - 215 (2007/10/02)
The sulfonation of benzene-SO2X (X = CH3, OCH3, OH, and Cl) and of 1- and 2-naphthalene-SO2X ( X = CH3, OCH3, and Cl) with sulfur trioxide in nitromethane as solvents has been studied.In the benzene series, substitution only occurs at the 3-position irrespective of X; the reaction rates, which are all within the same order of magnitude, are low.Upon sulfonation of the 1-SO2X-substituted naphthalenes, the main sulfonation product (58-80percent) is the 5-sulfonic acid (5-S); in addition, 6-S and small amounts of 3-S and 7-S are formed.Also, the formation of the intermolecular sulfonic anhydride of 1-(methylsulfonyl)naphthalene-5-S is observed.The 2-SO2X-substituted naphthalenes all yield the 5-S and 8-S in a ratio of ca. 4.9.For both the benzene and naphthalene series, insertion of SO3 between the SO2 and X moieties of the chlorosulfonyl and methoxysulfonyl substituents proper takes place.In the benzene series these reactions are fast as compared with the actual ring sulfonation, whereas in the naphthalene series they are, in general, relatively slow.In the naphthalene series the mesomeric directing effect of the SO2X groups is less important than in the benzene series; the "naphthalene α-effect" also plays an important role.
Kinetics of hydrolysis of aromatic mono- and disulfonyl chlorides
Sanecki, Przemyslaw,Rokaszewski, Edward
, p. 2263 - 2267 (2007/10/02)
A continuous polarografic method of recording instantaneous concentrations of - SO2Cl groups in an aqueous acetic acid system containing CH3CO2Na has been elaborated.Ten model monosulfonyl chlorides underwent hydrolysis according to pseudo-first order kinetics (20percent H2O, 80percent v.v.CH3CO2H, 0.5 mol/dm3 CH3CO2Na).Plots of hydrolysis for seven disulfonyl dichlorides with different number of - CH3 groups have been determined.Pseudo-first order rate constants for two consecutive reactions of hydrolysis (k1 and k2) have been computed and the influence of -SO2Cl and -SO3- groups on the reactivity of the second group - SO2Cl has been discussed.The mechanism of nucleophilic substitution has also been discussed.
