P[2,4,6-(OMe)3C6H2]3 in methanol T=20°C; 28 h;

1: 2,3,5-tri-O-acetyl-1-O-methyl-β-D-ribofuranose With water; acetic acid T=40°C; 2 h; 2: acetic anhydride With pyridine T=0 - 20°C;