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 MoreSuzhou Wedo Chemicals Co., Ltd.
Contact:86 512 58100425
Address:Zonger Road, DongSha Industry Park , Zhangjiagang, Jiangsu, China
Contact:+86-571-87010026
Address:202, Zhenhua Road,
Hefei EnliPharma Tecnology Co.,Ltd
Contact:0086-551-66399836
Address:Qing Cheng ShuiXiang Building 805, Mengcheng North Road , ShuangFeng Economic Development Zone Anhui HeFei
Nanyang Tianhua pharmaceutical Co.,Ltd.
Contact:+8618639816203
Address:Longsheng Industrial Park
Shandong Jusage Technology Co.,Ltd.
Contact:86-13406130167
Address:No.20,North Ride No.9 Road, Guangrao Economic Development Zone, Shandong Province
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)