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4-(2-Chloroethoxy)phenyl (CEP) aglycon belongs to the class of Janus aglycons and has already been used as a pre-spacer in the synthesis of neoglycoconjugates and as a temporary protective group in the synthesis of oligosaccharides. In the present work, a set of glycosides of various monosaccharides containing CEP aglycon was synthesized. The possibility of modification of CEP aglycon was demonstrated using the corresponding lactoside as an example.

New derivatives of serinol, 3-[4-(2-chloroethoxy)benzyloxy]-2-phthalimidopropan-1-ol and 3-[4-(2-azidoethoxy)phenoxy]-2-phthalimidopropan-1-ol, were synthesized and tested as glycosyl acceptors in stereoselective 1,2-cis-galactosylation in the benzyl-free synthesis of analogs of α-linked galactosylceramides. It was found that NIS/AgOTf-promoted glycosylation of 3-[4-(2-chloroethoxy)benzyloxy]-2-phthalimidopropan-1-ol with ethyl 4,6-O-(di-tert-butylsilylene)-1-thio-β-D-galactoside resulted in both the expected α-linked diastereomeric glycosides and the product of iodination of the benzyl group of the aglycon. This process was avoided by using the corresponding galactosyl imidate under Et3SiOTf promotion to give exclusively α-linked diastereometic serinol glycosides.

Efficient multigram two-step syntheses of 4-(2-chloroethoxy)phenol and 4-(3-chloropropoxy)phenol in >70% yields starting from 4-hydroxybenzaldehyde and reagents with general formula Cl(CH2) n X (X = Cl, n = 2; X = OTs, n = 3) are proposed. 4-(2-Chloroethoxy)phenol can also be conveniently prepared from 4-methoxyphenol and 1,2-dichloroethane. The compounds thus obtained can be used in carbohydrate chemistry to synthesize glycosides bearing "universal" 4-(ω-chloroalkoxy)phenyl aglycons.

Terminal disaccharide fragment of phenolic glycolipid from Mycobacterium leprae (PGL-I) was synthesized as a glycoside with 4-(2-aminoethoxy)phenyl aglycon. The obtained 4-(2-aminoethoxy)phenyl 4-O-(3,6-di-O-methyl-β-d-glucopyranosyl)-2,3-di-O-methyl-α-l-rhamnopyranoside was used for the synthesis of a series of neoglycoconjugates with bovine serum albumin with different degrees of substitution.

Spacered branched hexaarabinofuranoside, which corresponds to the terminal fragment of mycobacterial lipoarabinomannan and arabinogalactan, was synthesized via three different routes. Synthetic scheme which involved only acyl and silyl protective groups (benzyl-free approach) allows one to reduce the number of deprotection steps, enhance the overall yield, and keep the azido group until the end of the synthesis.

3,6-Di-O-methyl-β-d-glucopyranose neoglycoconjugates with bovine serum albumine and poly(acrylamide) carrier were obtained, which differ in the aglycon nature, linking pattern, and substitution degree.

aHigher Chemical College of the Russian Academy of Sciences, 9 Miusskaya pl., 125047 Moscow, Russian Federation. bN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation. Fax: +7 (095) 135 5328. E mail: kononov@ioc.ac.ru cA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, 119991 Moscow, Russian Federation. Fax: +7 (095) 135 5085. E mail: bre@ineos.ac.ru