4- Pyridyl thioglycosides

Photorearrangement of the anomeric pair of 4-pyridyl thioglycosides 805 followed by 5-methylation gave the two anomers of 807 in low yield (5%) (79JOC1892) (Scheme 224). 

On the other hand, reaction of the pyridyl thioglycoside 34 with alcohol 57 has been shown [76] to provide good yields of the j8-linked disaccharide 58 (Fig. 17). No mention was made of the formation of any a-glycoside product in this... 

Irradiation of the pyridyl thioglycoside (73) caused a complex isomerization to give the jS-iV-bonded compound (74) as well as the a- and j8-C-nucleosides bonded through C-3 and C-5. All were isolated in low yield only. The 1,2,4-thiadiazole thioglucoside (75) has been reported,and the acid- and almond /3-glucosidase-catalysed hydrolysis of the purine compound (76) and its 2 -deoxy analogue have been investigated. As expected, the latter is the more sensitive in acid solution, but the former is the better enzyme substrate. ... 

Deoxy-(2-pyridyl)thioglycoside 155, when activated by methyl iodide, reacts smoothly with sugar alcohol 156 to give 2 -deoxy-a-disaccharide 157 in good yield and high stereoselectivity (Scheme 36) [106]. 

Apart from n-pentenyl glycosides (/d) and thioglycosides (75), disarmed couplings have been demonstrated for 2-pyridyl-l-thioglycosides, 56, by Mereyala (24), and SBox glycosides, 57, by Demchenko (25) (Scheme 10a). 

The important role now played by thioglycosides as glycosyl donors is well established in Section 1 by the large number of disaccharides, in particular, whose syntheses have been effected by their use. Variations such as 5-pyridyl compounds and glycosyl xanthates were referred to and a further involves the use of acetylated glycosyl 1-piperidinecarbodithioates, eg (128), which have been assessed as suitable as glycosyl donors for the production of 1,2-rra/M-related glycosides. ... 

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