Sulfates and Related Esters

Cyclic sulfites and sulfates in organic synthesis have been reviewed in a Tetrahedron report. The reactions of several carbohydrate-based sulfite and sulfate derivatives with nitrogen, carbon and sulfur nucleophiles are reported. In the area of natural products, five sulfated saikosaponins containing the trisaccharide unit 28 have been isolated as minor constituents from Bupleurum rigidum. The leaf-movement hormones, sulfated phenolic glycosides 29, have been shown to be plant specific, rather than being common to all plants.  

The sodium salts (30) of heptakis (2-0-methyl-3,6-di-0-sulfo)cyclomaltohep-taose have been made for use as possible chiral resolving agents for capillary electrophoresis. The 3- and 6-monosulfated and the 3,6-disulfato-p-D-Gal-(l- 4)-[a-L-Fuc-(l- 3)]-p-D-GlcNAc-(1 3)-p-D-Gal-(l- 4)-D-Glc have been 

Reagents i, SOlrrig ii, Nal04, RUCI3 iii, Na2S iv, HsO v, AcgO, Py 

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Phosphamides, A-Sulfates and Related Esters - 5- -,3-0-Cyclic phos-phamides have been prepared by reaction of 5-amino-5-deoxy-l,2-0-isopropyl-idene-a-D-xylofuranose with either phenylphosphonic dichloride or phosphoryl chloride, and their conformations determined. Chemo-selective -sulfation of 2-amino-2-deoxy-P-D-glucopyranose derivatives with a single free hydroxy-group was achieved with phenyl chlorosulfate followed by hydrolysis in aqueous NaHC03. ... 

G. M. Powell, A. H. Olavesen, The fate of Sulfate Esters in vivo , in Sulfation of Drugs and Related Compounds , Ed. G. J. Mulder, CRC Press, Boca Raton, Florida, 1981, p. 187-212. 

Whereas the phosphetanium (Sect. 2.2) derivatives undergo base-catalyzed hydrolysis with essentially complete retention of configuration, the reaction with the related thietanium salts proceeds with complete inversion of configuration and can be described simply as a direct nucleophilic substitution 35. As far as the author is aware, no exchange evidence of the type er countered in the acid-catalyzed hydrolysis of ethylene phosphate, has been found for the cyclic sulfate esters. Consequently despite the geometrical similarities between the cyclic sulfates and phosphates and the related hybridization of the central atoms, the situation in which a finite pentacovalent intermediate sulfur species exists has not been delineated (restricting the discussion to esters). 

Treatment of diethyl malonate and related compounds with 1,2-dihaloethane in the presence of base constitutes a classical method of cyclopropane synthesis296"300. The reaction can be conveniently carried out under PTC conditions. An improved method utilizing solid-liquid phase transfer catalysis has been reported298. The reaction of dimethyl or diethyl malonate with 1,2-dibromoalkanes except for 1,2-dibromethane tends to give only low yields of 2-alkylcyclopropane-l, 1-dicarboxylic esters. By the use of di-tm-butyl malonate, their preparations in satisfactory yields are realized (equation 134)297. The 2-alkylcyclopropane derivatives are also obtained from the reaction of dimethyl malonate and cyclic sulfates derived from alkane-1,2-diols (equation 135)301. Asymmetric synthesis... 

Arene(tricarbonyl)chromium complexes, 19 Nickel boride, 197 to trans-alkenes Chromium(II) sulfate, 84 of anhydrides to lactones Tetrachlorotris[bis(l,4-diphenyl-phosphine)butane]diruthenium, 288 of aromatic rings Palladium catalysts, 230 Raney nickel, 265 Sodium borohydride-1,3-Dicyano-benzene, 279 of aryl halides to arenes Palladium on carbon, 230 of benzyl ethers to alcohols Palladium catalysts, 230 of carboxylic acids to aldehydes Vilsmeier reagent, 341 of epoxides to alcohols Samarium(II) iodide, 270 Sodium hydride-Sodium /-amyloxide-Nickel(II) chloride, 281 Sodium hydride-Sodium /-amyloxide-Zinc chloride, 281 of esters to alcohols Sodium borohydride, 278 of imines and related compounds Arene(tricarbonyl)chromium complexes, 19... 

Conjugation of 0-, N- and S-contalnlng functional groups with sulfate Is very common In animal systems. Sulfate Is transferred from adenosine 3 -phosphate-5 -sulfatophosphate (PAPS) by a variety of transfer enzymes. The mechanisms for sulfation of xenobiotics (74,75) and the chemistry of sulfate esters and related compounds and the synthesis of these have been reviewed (75-77). Syntheses of 0-, N- and S-sulfate conjugates of xenobiotics may be carried out by the methods described below. 

After methylation of compounds (50, R = Me) and (51, R=Me) with methyl sulfate, four isomeric pyranosides were isolated by gas-liquid chromatography by detailed nuclear magnetic resonance studies, these were shown to exist in the H° conformation.103 Unlike related esters (see p. 221), but like other 2,3-unsaturated glycosides (see p. 237), these anomeric pairs of glycosides were found to conform with Hudson s isorotation rules. In dilute acid, they are degraded to methyl 3,4-dideoxy-6-0-methyl-a- and /3-D-g/ycero-hex-3-enopyrano-sidulose (52) these also were characterized configurationally and conformationally by nuclear magnetic resonance methods. 

Pregnancy urine has been found to be a rich source of estrogens and related compounds. They are generally excreted as sulfates or glucu-ronosides, and are liberated from the esters by acid hydrolysis, phenol-sulfatase, and j8-glucuronidase. The 18-carbon steroids isolated from mammalian urine show close similarity (Table VIII and Fig. 18). They... 

Jetten, A.M., M.A. George, G.R. Pettit, C.L. Herald, and J.I. Rearick Action of Phorbol Esters, Bryostatins, and Retinoic Acid on Cholesterol Sulfate Synthesis Relation to the Multistep Process of Differentiation in Human Epidermal Keratino-cytes. J. Invest. Dermatol. 93, 108 (1989). 

The -butyl ester is a relatively hindered ester, and many of the following methods for its formation should be, and in many cases are, equally effective for the preparation of other hindered esters. The related 1- and 2-adamantyl esters have been used for the protection of aspartic acid and other amino acids (1-AdOH, toluene, dimethyl sulfate, cat. TsOH, 70-80% yield). ... 

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