L-D-Glucopyranose

I. Cerny, T. Trnka, and M. Cerny, Preparation of 2-amino-2,4-dideoxy-D-lyxo-hexopyranose (4-deoxy-D-mannosamine) from l,6-anhydro-/l-D-glucopyranose, Collect. Czech. Chem. Commun., 48 (1983) 2386-2394. 

M. Cerny, I. Cerny, and T. Trnka, Ammonolysis of l,6-anhydro-2,4-di-0-tosyl-/l-D-glucopyranose and l,6 3,4-dianhydro-2-0-tosyl-/l-D-galactopyranose preparation of 4-amino-l,6-anhydro-4-deoxy-/J-D-manno- and -/1-D-altropyranose, Carbohydr. Res., 67 (1978) 33-41. 

Institut of Physical and Chemical Research, 3-Azido-l,6-anhydro-3-deoxy-2,4-di-0-benzyl-/l-D-glucopyranose, Japan Kokai Tokkyo Koho JP 57181094 Chem. Abstr., 98 (1983) 126566. 

Other trisaccharides which, it has been suggested, occur in combination with flavonoids in plants are 0-/3-D-glucopyranosyl-(l— 2)-0-a-ii-rhamno-pyranosyl-(l- )-D-glucopyranose as a kaempferol derivative in potato flowers,and a galactosylsophoroside of kaempferol in Pisum arvense. -However, for both, a great deal more work is required before these structures can be fully accepted. 

Fig. 9. Partial structural formulas and shorthand notations for principal hemiceUuloses found in wood, where the sugar units ate noted as P-D-xylopyranose (Xylp), 4-Omethyl-a-D-glucopyranosyluronic acid (GlupU), a-L-arabinofuranose (Araf), P-D-glucopyranose (Glup), P-D-mannopyranose (Manp), and P-D-galactopyranose (Galp) for (a) arabino-4-O-methylglucuronoxylan from softwood, (b) 0-acetyl-galactoglucomannan from softwood, and...

Acetalation. As polyhydroxy compounds, carbohydrates react with aldehydes and ketones to form cycHc acetals (1,13). Examples are the reaction of D-glucose with acetone and a protic or Lewis acid catalyst to form l,2 5,6-di-0-isoprop5lidene-a-D-glucofuranose [582-52-5] and its reaction with benzaldehyde to form 4,6-0-benzyhdene-D-glucopyranose [25152-90-3]. The 4,6-0-(l-carboxyethyhdine) group (related to pymvic acid) occurs naturally in some polysaccharides. 

Conversion of l,6-anhydro-4-0-benzyl-2 deoxy 2-fluoro-p-D-glucopyranose to the corresponding oxo derivative is earned out by ruthenium tetroxide generated in situ from ruthenium dioxide [54] (equation 49)... 

In addition to the above mentioned 4J couplings, we have now observed several examples of couplings across five bonds—i.e. 5J. For example, the ribopyranose derivative (13) shows a coupling of ca. 0.1 Hz between Hx and H4. Further examples occur in the spectrum of 2,3,4-tri-0-acetyl-l,6-anhydro-/ -D-glucopyranose (12), where Ji,4 = ca. 0.1 Hz and J2,5 = 0.5 Hz. Whether it is significant that these couplings all occur between equatorially oriented protons must await further studies. 

Thus the trans relationship between the hydroxymethyl group and the C-l hydroxy group in a-D-glucopyranose, and the cis relationship between the methyl group and the C-l hydroxy group in P-L-fucopyranose, are clearly shown. Note that representation of ketoses may require a different modification of the Fischer projection, as shown in the fructofuranose example above. Here C-2 is rotated about the bond with C-3 to accommodate the long bond to C-2 from the oxygen at C-5. 

Methyl 2,6-anhydro-a-D-altropyranoside-2 5B g l,4-Anhydro-ot-D-allopyranose-Bi,4 9 1,2-0-Ethylidene-a-D-glucopyranose- S3 10 p-L-Altropyranose-2So... 

Note. The alternative name using a substituent prefix (see 2-Carb-35.1) is 3,4,6-tri-0-acetyl-2-amino-2-deoxy-l-0,2-N-[(methylamino)methylylidene]-a-D-glucopyranose. 

Nigerose Nojirimycin Noviose a-D-Glucopyranosyl-(1- 3)-D-glucose 5- Amino-5-deoxy-D-glucopyranose 6- Deoxy-5-C-methyl-4-Omethyl-L-/yxo-hexose... 

An acylated glycosyl halide, such as a 2,3,4,6-tetra-O-acetyl derivative, is treated with thiourea. The resulting pseudothiouronium salt is hydrolyzed with aqueous potassium carbonate to give the 2,3,4,6-tetra-0-acetyl-l-thio-(3-D-glucopyranose,48 which then is alkylated. 

P-D-fructofuranose a-D-glucopyranose 1,2 2,1 -dianhydride a-D-fructofuranose a-D-glucopyranose 1,1 2,2 -dianhydride P-D-fructofuranose a-D-glucopyranose 1,1 2,2 -dianhydride P-D-fructopyranose a-D-glucopyranose 1,1 2.2 -dianhydride P-D-fructofuranose a-D-glucopyranose 2,1 3,2 -dianhydride P-D-fructopyranose a-D-sorbopyranose 1,2 2,1 -dianhydride P-D-fructopyranose a-L-sorbopyranose 1,2 2,1 -dianhydride di-a-L-sorbofuranose 1,2 2,3 -dianhydride a-l-sorbofuranose a-L-sorbopyranose 2,1 3,2 -dianhydride di-a-L-sorbopyranose 1,2 2,1 -dianhydride a-D-sorbopyranose a-L-sorbopyranose 1,2 2,1 -dianhydride di p-L-sorbopyranose 1,2 2,1 -dianhydride a-L-sorbopyranose p-L-sorbopyranose 1,2 2,1 -dianhydride a-L-sorbofuranose a-L-sorbopyranose l,2 2,l -dianhydride P-L-sorbofuranose a-L-sorbopyranose 1,2 2,1 -dianhydride a-L-sorbofuranose P-L-sorbofuranose l,2 2,l -dianhydride... 

Cyclodextrins (CDs) are cyclic a-l,4-linked D-(- -)-glucopyranose units (a-CD = six units jS-CD = seven units) that form inclusion complexes with a variety of hydrophobic molecules in aqueous medium [64]. 

A facile synthesis of carba- -D-glucopyranose (99) and its l antipode (104) was accomplished by means of resolution of the starting compound DL-( 1,3,5/2,4)-2,3-diacetoxy-4,5-dibromocyclohexane-1 -carboxylic... 

Debenzylation of 122 and 123, followed by acetylation, afforded the pentaacetates 98 and 124, which were respectively converted into carba-a-D-glucopyranose (99) and carba-/ -L-altropyranose (125) on hydrolysis. ... 

Similarly, 180 was transformed into 5a-carba-a-D-glucopyranose penta-acetate (98) and 5a-carba- 8-L-idopyranose pentaacetate (183). 

Sharpless reaction of the enantiomeric alkenes (47) produced the precursors for 2-amino-2-deoxy-o -D and -L-carba-glucopyranoses. These compounds were converted into the penta-7V,0-acetates by the following sequence. Replacement of the bromo group with an acetate ion, treatment with sodium in liquid ammonia, and peracetylation. 

Trideoxy-2,3,4-trifluoro-D-galacto- and -gluco-pyranosyl derivatives 391 and 392 have been prepared from l,6-anhydro-4-(9-benzyl-2-deoxy-2-fluoro-/ -D-glucopyranose (385) by use of DAST, through several intermediates, as shown [385 386,10% 387- 388,72% 389 390,90% refl. toluene (for 385) or dichloromethane (for 387 and 389), 24 h]. 

---