Tetrahedron p. 1281 - 1287 (2011)
Update date:2022-08-05
Topics:
Desoky, Ahmed Y.
Hendel, Jennifer
Ingram, Laura
Taylor, Scott Douglas
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.
View MoreHangzhou Share Chemical Co., Ltd(expird)
Contact:+86-57187093700
Address:Hang Xing Road
ShanDong XinDa Chemical CO.,LTD(expird)
Contact:086-0311-87580543
Address:No.168, High Technology Development Zone Jinan Shandong China
Zhejiang PRIMAR Import & Export Trade Co., Ltd.
Contact:86-570-3630818
Address:No.1Puzhuyuan,Quhua,Zhejiang Province,China324004
Changzhou Anyi Biochem Co., Ltd.(expird)
Contact:+86-519-88836158
Address:no,51 caoda
Zouping Fuhai Technology Development Co., Ltd.
Contact:+0532-86934525 18660293207
Address:jiuhu town industrial park Zouping County,bingzhou Provincejiuhu town industrial park
Doi:10.1007/BF00487302
(1989)Doi:10.1007/BF00764806
(1990)Doi:10.1016/j.bmcl.2010.12.048
(2011)Doi:10.1016/S0040-4039(01)80570-0
(1989)Doi:10.1021/jo00299a033
(1990)Doi:10.1055/s-1995-4088
(1995)