L-Galactopyranose

Agarose is closely approximated as the alternating copolymer of (1 3)-/3-D-galactopyranose and (l- 4)-3,6-anhydro-a-L-galactopyranose (see formula 5). 

Fig. 3. The 13C NMR spectrum of a sulfated xylogalactan from the calcareous red alga Corallina pilulifera (X—signals of the corresponding carbon atoms of nonreducing unsubstituted /J-D-xylopyranosyl branches, L-6—signal of C-6 of 4-linked a-L-galactopyranose residues of the backbone, adapted from ref. 166).

M. Jaseja, A. S. Perlin, O. Dubinsky, D. Christiaen, S. S. (Malis) Arad, andR. Glaser, N.m.r. structure determination of 3-0-(a-D-glucopyranosyluronic acid)-L-galactopyranose, an aldobiuronic acid isolated from the unicellular red alga Rhodella reticulata, Carbohydr. Res., 186 (1989) 313-319. 

All substituents, except for the -OH at C4, are equatorial in the more stable conformation of p-L-galactopyranose. 

Alternating 1,3-linked jff-D-galactopyranose and 1, 4-linked 3,6-anhydro-of-L-galactopyranose... 

Hanaya, T, Yasuda, K, Yamamoto, H, Yamamoto, H, Stereoselectivity in the preparation of 5,6-dideoxy-5-dimethoxyphosphinyl-D- and -L-hexofuranoses, and an efficient synthesis of 5,6-dideoxy-5-hydroxyphosphinyl-L-galactopyranose (a P-in-the-ring L-fucose analogue). Bull. Chem. Soc. Jpn., 66, 2315-2322, 1993. 

Problem 25.13 Draw /8-L-galactopyranose in its more stable chair conformation, and label the substituents as either axial or equatorial. 

Porphyran 3,6-anhydro-a-L-galactopyranose and L-galactopyranose 6-sulfate /S-D-galactopyranose and its 6-methyl ether 40-42... 

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