Galactose was acetylated to β-pentaacetyl-D-galactose which was brominated with glacial acetic acid saturated with hydrogen bromide at 0° to from α-acetobromo-D-galactose. Condensation of this brominated compound with fatty alcohols by the König-Knorr reaction, using silver oxide in chloroform, afforded alkyl 2, 3, 4, 6-tetra-O-acetyl-β-D-galactopyranosides, which was finally deacetylated with 0.01
N sodium methoxide, forming 10 kinds of alkyl β-D-galactopyranosides; viz. butyl compound, m.p. 101°; pentyl, m.p. 117°, hexyl, m.p. 118.5°; octyl, m.p. 109.5°; decyl, m.p. 152° (t.p. 103°); dodecyl, m.p. 159° (t.p. 101.5°); tetradecyl, m.p. 168° (t.p. 102°); hexadecyl, m.p. 161° (t.p. 102°); octadecyl, m.p. 154° (t.p. 103°); and
cis-9-octadecenyl, m.p. 138
(t.p. 56°).
Similarly, alkyl β-D-glucopyranosides and their acetyl derivatives were prepared; viz. tetradecyl compound, m.p. 150° (t.p. 83°); hexadecyl, m.p. 145° (t.p. 82.5°); octadecyl, m.p. 120° (t.p. 81.5°); and
cis-9-octadecenyl as a syrup. Their acetyl derivatives were: Tetradecyl, m.p. 69°; hexadecyl, m.p. 73.5°; octadecyl, m.p. 79.5°; and
cis-9-octadecenyl, b.p
0.05 252°. (t.p.: transition point).
Of these, alkyl galactosides with larger number of carbon than decyl, and alkyl glucosides are considered to form liquid crystals.
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