2-5-ethyl-2-thio

Ethyl 1-thio-p-o-glucopyranoside 4-(a-D-Ribofuranosylthio)benzoic acid... 

Using the ethyl 1 -thio derivative (97) of 2,3,4-tri-O-benzoyl-D-xylose, the fully protected and free O-glycopeptides 99 and 100, having the TV-terminal amino acid sequence 3 to 6 (98) of the protein core of a proteodermatan sulfate have been prepared (69). 

Ethyl 1-thio /J-maltoside 6 -0-trityl-hexa-O-acetyl- 101-103 + 71 C 44... 

Growth substrate Maltose (mM) Methyl a-D-glucopyranoside (mM) Ethyl 1-thio-a-D-glucopyranoside (mM) References Comments... 

A solution of ethyl 1-thio- p-D-galactopyranoside (5 g, 12.9 mmol) and dibutyhin oxide (3.2 g, 13 mmol) in MeOH (500mL) was boiled under reflux for 4 h. Removal of the solvent gave a white powder that was dissolved in dry THF (500mL). r-Butyldimethylsilylchk>ride (1.95 g, 13 mmol) was added to the solution and left to stir for 24 h at room temperature, after which time TLC (9 1, CHjClj/MeOH) showed that no starting material remained. 

In 1916, Schneider and Sepp 1 prepared ethyl 1-thio-a-glucofuranoside by treating an aqueous solution of one mole of the diethyl dithioacetal with one mole of mercuric chloride, and maintaining neutrality by neutralizing the hydrochloric acid formed with aqueous sodium hydroxide. The product was regarded by them os a normal (i.e., pyranoid) 1-thiogly-... 

Wolfrom and coworkers88-71 were able to prepare various 1-thio-a-D-galactofuranosides, generally isolated as the acetates, after purification by column chromatography. Thus, the Pacsu and Wilson method gave sirupy ethyl 1-thio-a-D-galactofuranoside, and a crystalline acetate. This product was also obtained by treatment of the dithioacetal with dilute hydrochloric acid and then mercuric oxide. Ethyl 2-acetamido-2-deoxy-l-thio-a-D-galactofuranoside was prepared in 32% yield, and the /3-d anomer in 3% yield. 

Whereas ethyl l-thio-d-D-arabinofuranoside cannot be prepared directly, the 5-O-benzoyl diethyl dithioacetal gave 38% of ethyl 5-O-benzoyl-l-thio-0-D-arabinofuranoside, which was debenzoylated to the desired product. The 5-benzoate of ethyl 1-thio-a-D-ribofuranoside was similarly prepared.88 Two other compounds, ethyl 2-acetamido-2-deoxy-l-thio-/3-L-arabino-furanoside72 and ethyl 2-acetamido-2-deoxy-l-thio-a-D-xylofuranoside,73 were prepared from the corresponding d-galacto and d-gluco analogs by periodate oxidation, and subsequent borohydride reduction of the product. 

A new route, from 1-thio-D-aldohexofuranosides, was developed by Wolfrom and coworkers ethyl 1-thio-a-D-glucofuranoside was converted by chlorine into the chloride,101 arid this was condensed with the chloro-mercuri derivative of a 2,6-diacetamidopurine to give, on partial deacetylation, a 2-acetamido-9- f-D-glucofuranosyladenine.70 D-Galactofuranosyl analogs were also prepared. 

Similarly, establishment of a furanoid ring in a compound of undetermined structure was applied by Green and Pacsu82 to ethyl 1-thio-a-D-glucofuranoside the observed specific rotation of this compound in aqueous... 

The allyl glycoside of a-D-Abe-(l ->3)-a-D-Man 115 was prepared by a different approach.200 The ethyl 1-thio-D-abequopyranoside donor 113 was obtained from methyl (3-D-galactopyranoside derivative 110 according to Scheme 33. The cyclic sulfate intermediate 111 was the precursor for the stereoselective reduction with tetrabutylammonium borohydride to 112 which was further derivatized to the thioglycosyl donor 113. Donor 113 was reacted with acceptor 114 to give 115 after deprotection. 

The thioglycoside derivative of 4,6-dideoxy-i-/vA o-hexopyranose 160, useful as glycosyl donor has been prepared starting from the ethyl 1-thio-a-L-rhamnopyranoside (159, Scheme 46). 

In an alternative route employing fewer overall steps, Borbas and Lipt k119 synthesized the trisaccharide hapten as a 4-aminophenyl glycoside protected as the (V-trifluoroacetyl derivative 13 for potential conjugation to protein.108 Ethyl 1-thio-a-L-rhamnopyranoside as the 2,3-O-diphenylmethylene acetal 23 was the precursor for both rhamnosyl residues. Condensation of 23 with glycosyl bromide 24 with silver triflate as promoter, followed by O-deacetylation and O-benzyliden-... 

Ethyl 1 -thio-0-D-galactopyranoside Acetal Benzene TBAB 63 Allyl bromide 0 60 0 197... 

Ethyl 1-thio-a-D-mannopyranoside Acetal DMF CsF Amb. Benzyl bromide 0 3,6 59 0 218... 

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