5-Ethyl glycosides

The first total synthesis of the marine dolabellane diterpene (+)-4,5-deoxy-neodolabelline (70) was accomplished by D. R. Williams et al. [58]. The trans-disubstituted dihydropyran moiety in key intermediate 69 was efficiently prepared from mixed acetal 66 by RCM with second-generation catalyst C and subsequent Lewis acid-catalyzed allylation of ethyl glycosides 67 with allylsi-lane 68 (Scheme 12) [59]. 

Table X), sweetness is not normally observed for ethyl glycosides, and does not occur at all for sugars having larger aglycons these are either bitter or very bitter. ...

K. P. Ravindranathan and H. J, Jennings, A facile, one-step procedure for the conversion of 2-(trimethylsilyl)ethyl glycosides to their glycosyl chlorides, Tetrahedron Lett. 31 2537 (1990). 

The presence of the glycosyl chloride was demonstrated by its conversion into an ethyl glycoside by ethanol in the presence of a silver salt. The hypochlorite ester formed by chlorinolysis of a methyl glycoside underwent... 

The a-anomer of the deacetylated XXX can also be obtained readily through hydrogenation of the ethyl glycoside of D-pseudoglucal (XXVIII).16... 

Hydrogenation of diacetyl-D-arabinal leads to diacetyl-dihydro-D-arabinal.30 In addition, a 4-acetyl-D-pseudoarabinal (XL) has been prepared and from it an ethyl glycoside, probably a mixture, was obtained.30-34... 

Jansson, K, Ahlfors, S, Erejd, T, Kihlberg, J, Magnusson, G, Dahmen, J, Noori, G, StenvaU, K, 2-(Trimethylsilyl)ethyl glycosides. 3. Synthesis, anomeric deblocking, and transformation into 1,2-trans 1-O-acyl sugars, J. Org. Chem., 53, 5629-5647, 1988. 

The chiral oxadiene 281 adds to ethyl vinyl ether giving a 2 1 mixture of endo adducts (-h)-282 and (—)-283. Deacylation of pure (-f)-282 delivers 284, which is then protected as a silyl ether to give 285. Raney nickel reduction and deprotection provides ethyl glycoside 286. Protection of 284 as a benzyl ether, followed by desulfurization and subsequent hydroboration and deprotection, provides (-)-L-olivose [150] (Scheme 13.80). 

In this ring-closing metathesis reaction (RCM) of diene 17 an anomeric mixture (1 1) of ethyl glycoside 19 is obtained. 

Another method was reported in 1919 for obtaining soluble starch by refluxing the starch granules in 95% ethanol, containing 0.2-1.6% (w/v) HCl for 6-15 min [141]. The product is called Small s soluble starch. It is soluble (10mgml ) in hot water and has a low reducing value due to the formation of ethyl-glycosides at the hydrolytic points. 

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