3.6- anhydro-L-galactose

For the properties of the methyl derivatives of 3,6-anhydro-L-galactose see Advances in Carbohydrate Chemistry, 2, 77 (1946).)... 

L-Gulose readily forms an anhydride, and in a study on alginic acid, methylated L-guloses were isolated as their anhydrides.88 Other anhydro sugars, such as 3,6-anhydro-L-galactose and its 2-methyl ether, may be found in algae (see, for example, Ref. 412), and, under certain circumstances, 2,3,6-tri-O-methyl-D-galactose may form an anhydride.571... 

Hands and Peat,8 and Percival, Somerville and Forbes9 isolated from methylated agar a compound which was found to be a derivative of 3,6-anhydro-L-galactose. The components of agar and their relative amounts will be described in some detail in the following sections. 

Y. Hama, H. Nakagawa, T. Sumi, X. Xia, and K. Yamaguchi, Anhydrous mercaptolysis of agar an efficient preparation of 3,6-anhydro-L-galactose diethyl dithioacetal, Carbohydr. Res., 318 (1999) 154-156. 

SCHEME 4. Total reductive hydrolysis of a galactan of the agar group containing 3,6-anhydro-L-galactose and its 2-methyl ether (borane-4-methylmorpholine complex in 2 M CF3C02H, 8 h at 100 °C, according to refs.213 214... 

D. A. Rees, Enzymic synthesis of 3 6-anhydro-L-galactose within porphyran from L-galactose 6-sulphate units, Biochem. J., 81 (1961) 347-352. 

None of the enzymes in this system are difficult to obtain. However, it is advantageous to immobilize them on an insoluble support. For this purpose, agarose, a natural polysaccharide from D-galactose and 3,6-anhydro-L-galactose, is particularly well suited to this work on a laboratory scale. The support is first activated with cyanogen bromide. Figure 10.5 shows the activation mechanism of a cjj-diol system and its coupling with the enzyme symbolized by E-NH2 via... 

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