- Sulfation of various alcoholic groups by an arylsulfate sulfotransferase from desulfitobacterium hafniense and synthesis of estradiol sulfate
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Bacterial arylsulfate sulfotransferases (AST) are enzymes that catalyse the transfer of a sulfate group from p-nitrophenyl sulfate (p-NPS) to a phenolic acceptor molecule. By screening of the NCBI protein database a gene coding for an AST was found in Desulfitobacterium hafniense. After expression the enzyme was purified and characterised. This AST efficiently sulfates various acceptor molecules (estrone, estradiol, enkephalin and non-phenolic alcohols) using p-NPS as sulfate donor. The purified AST has a pH optimum of 9.6, it is stable in the presence of 10% of DMSO, and depending on the conditions it has a melting temperature of up to 47°C. Surprisingly, and in great contrast to all other known bacterial ASTs, this enzyme was able to use a variety of non-phenolic alcohols as sulfate acceptor. Because of these properties, this unique enzyme is a promising tool for biotransformation processes, providing a green and simple method to specifically sulfate compounds without need for functional group protection.
- Van Der Horst, Michael A.,Van Lieshout, Johan F. T.,Bury, Aleksandra,Hartog, Aloysius F.,Wever, Ron
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supporting information
p. 3501 - 3508
(2013/02/22)
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- Preparation of trifluoroethyl- and phenyl-protected sulfates using sulfuryl imidazolium salts
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Sulfuryl imidazolium salts (SIS's), a new class of sulfating agents, were prepared bearing the trifluoroethyl (TFE) and phenyl groups, two functionalities that have been used for the protection of sulfate monoesters, by subjecting the corresponding sulfonyl imidazoles with methyl triflate. In contrast, SIS's bearing the electron donating neopentyl and isobutyl groups, two moieties that have also been used for the protection of sulfates, were found to be unstable and could not be isolated though SIS's bearing electron donating aryl groups, such as a p-methoxyphenyl or p-thiomethylphenyl group were readily prepared and are stable compounds. In most instances, TFE-protected phenolic and carbohydrate sulfates were obtained in good yield by reaction of the corresponding SIS's with steroids and carbohydrates. Phenyl-protected carbohydrates were also readily prepared using the corresponding SIS's. Those SIS's having a methyl group at the 2-position of the imidazole ring were, in general, superior sulfating agents to those, which lacked a methyl group at this position. The use of SIS's to prepare TFE-protected sulfates represents a significant improvement of the previous reported procedure, which involved treating unprotected sulfates with trifluorodiazoethane. The TFE protecting group was removed from steroidal sulfates and secondary sulfates in carbohydrates in high yields using NaN3 in warm DMF, conditions that are less vigorous than those previously reported for removing this group. Deprotection of TFE-protected 6-sulfated carbohydrates using NaN3 in warm DMF proceeded in lower yields due to partial desulfation.
- Desoky, Ahmed Y.,Hendel, Jennifer,Ingram, Laura,Taylor, Scott Douglas
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supporting information; experimental part
p. 1281 - 1287
(2011/03/23)
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- PROCESS FOR SELECTIVE SULFATION OF AROMATIC HYDROXYL GROUPS
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The present invention relates to processes for selective sulfation of an aromatic hydroxyl group over an aliphatic hydroxyl group where both are present in the same molecule. This invention also relates to processes for selective sulfation of the aromatic hydroxyl group of equilin, equilenin, estradiol, estra(1,3,5-triene)-3,16,17-triol, dihydroequilenin or dihydroequilin. This invention further relates to alkali metal salts of dihydroequilenin sulfates, dihydroequilin sulfates, estradiol sulfates, and estriol sulfates, processes for making thereof, stable compositions comprising thereof, and the use thereof.
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Page/Page column 15-16
(2008/12/07)
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