Alkyl glycosides

The study of N-alkylation provides models for protonation, tauto-merism, and elucidation of structures, e.g., N-glycosides. Alkylation of MOT (3) with an alkyl halide (RX) and alkali does not lead to ether 33 but to a mixture of N-3- and N-4-alkyl derivative (34 and 35, resp. Scheme 17). 

Glycosides are obtained by conversion of the cyclic semiacetal form of aldoses and ketoses to an acetal. We will focus on the metal complexes and esters of the following glycosides alkyl pyranosides, alkyl furanosides, non-reducing disaccharides, polysaccharides, and Anally the nucleosides as a member of the group of iV-glycosides. 

Fig. 2. Dihydrochalcone glycoside (49), where R = H, OH, or O—alkyl and R = glucosyl, mtinosyl, neohesperidosyl, or xylosyl.

Pyran-4-one, 2,2,5-trimethyl-2,3-dihydro-photodimerization, 3, 720 4H-Pyran-4-one, 2,3-dihydro-2,3,5-trimethyl-6-( 1 -methyl-2-oxobutyl)-synthesis, 3, 844 Pyranones alkylation, 2, 56 aromaticity, 3, 632, 633 C NMR, 3, 587, 635 H NMR, 3, 580 cardiac glycosides, 3, 883 chromone synthesis from, 3, 830 colour couplers... 

The hydroxy compound 59 has been acetylated (94AJC991), and many glycosides have been protected by acetylation. The 4-thione 209 (85LA1922) and the 3-thiol 210 (83USP4419516) have been alkylated using methyl iodide with potassium hydroxide and chloroacetonitrile with triethylamine respectively. 

Glycosides are named by first citing the alkyl group and then replacing the -ose ending of the sugar with -oside. Like all acetals, glycosides are stable to neutral water. They aren t in equilibrium with an open-chain form, and they don t show mutarotation. They can, however, be converted back to the free monosaccharide by hydrolysis with aqueous acid (Section 19.10). 

Alkyl glycosides. Quick to biodegrade. Made from oils and sugar. 

Note. The parentheses are inserted to distinguish between the ester alkyl group (cited first) and the glycosidic O-alkyl group. 

Note. Acyl substituents on anomeric OH are designated (as above) by 0-acyl prefixes. However, anomeric 0-alkyl derivatives are named as glycosides (see 2-Carb-33). 

If the reducing terminal is a uronic ester glycoside, the ester alkyl group is cited at the beginning of the name, and the aglyconic alkyl group is cited with the name of the glycosidic residue. 

For example, for alkyl (8-16) glycoside (Plantacare 818 UP) non-ionic surfactant solution of molecular weight 390 g/mol, an increase in surfactant concentration up to 300 ppm (CMC concentration) leads to a significant decrease in surface tension. In the range 300 < C < 1,200 ppm the surface tension was almost independent of concentration. In all cases an increase in liquid temperature leads to a decrease in surface tension. This surface tension relaxation is a diffusion rate-dependent process, which typically depends on the type of surfactant, its diffusion/absorption kinetics, micellar dynamics, and bulk concentration levels. As the CMC is approached the absorption becomes independent of the bulk concentration, and the surfactant... 

Beau and Sinay described a method which laid the groundwork for cyanohydrin acetonide alkylations [1]. Their strategy involved alkylation and reductive desulfonylation of glucopyranosyl sulfones 4. In this one-pot procedure, low temperature alkylation and subsequent reductive desulfonylation with lithium naphthalenide generated -C-glycosides with good selectivity >10 1 j3 a) and in moderate to good yield (Eq. 1). 

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