Tetrahedron p. 5487 - 5494 (1988)
Update date:2022-08-02
Topics:
Kunz, Horst
Pfrengle, Waldemar
In the presence of Lewis acid catalysts O-acetyl- (1) and O-pivaloyl- (2) protected β-D-galactopyranosylamines react with aldehydes, isocyanides and carboxylic acids in Ugi-four-component-condensations to give the corresponding N-galactosyl-amino acid amide derivatives 3, 5 in almost quantitative yields.Zinc chloride is the most effective Lewis acid catalyst.At 0 deg C or even at room temperature the (2R,β-D)-diastereomers of the amino acid derivatives 3, 5 are formed with high diastereoselectivity.If the sterically more demanding O-pivaloyl galactosylamine 2 is used at -78 deg C to -25 deg C the stereoselectivity often exeeds 20:1 favouring the (2R,β-D) diastereomers 5.After one recrystallisation pure (R)-amino acid derivatives 5 are obtained in yields of 80-95percent.In addition to the high yields and stereoselectivity the amino acid synthesis described here has the further advantage that it neither requires organometallic reagents and intermediates nor exclusion of oxygen and moisture.Two step acid hydrolysis of the N-galactosylamino acid amide derivatives 5 delivers the enantiomerically pure (R)-amino-acids 8 in high yields.
View Morewuxi leji biology technology co., LTD
website:http://www.lejibio.com/
Contact:18362718864
Address:The Nanyue Road No. 2, Yixing City, Jiangsu Province
Liao Cheng All Win Chemicals Co.,LTD
Contact:86+0635-2991582
Address:Room 402,Unit 1,No.27 building.Zhong tong shi dai haoyuan,liaocheng city,Shan dong Province.China
Shanghai Kangxin Chemical Co., Ltd
Contact:+86 21 60717227
Address:118,Ganbai Village,Waigang Town,Jiading District,Shanghai
YanCheng LongShen Chemical Co.,Ltd.
Contact:+86-515-86668866
Address:No.13,Weiyi Road,Funing Aoyang Industrial Park
website:http://www.win-winchemical.com
Contact:0086-577-64498589
Address:6F, No. 396 Xingping Road, Longwan Industrial Zone, Wenzhou City, Zhejiang, 325000 P.R.China
Doi:10.1039/b909715e
(2009)Doi:10.1007/BF00773610
()Doi:10.1016/0022-328X(94)05077-O
(1995)Doi:10.1007/BF00962523
(1988)Doi:10.1016/j.tetlet.2009.09.115
(2009)Doi:10.1039/b915085d
(2009)