| 摘要 |
21,31-O-Alkylidene ribonucleosides are prepared by reacting a ribonucleoside with a ketone in the presence of hydrogen chloride at a temperature of from 5 DEG to 25 DEG C., the concentration of hydrogen chloride based on said ketone being from 10 to 20% by weight. A portion of the hydrogen chloride may be formed in situ by carrying out the reaction in the presence of phosphorus trichloride, phosphorus pentachloride or phosphorus oxychloride dehydrating agents. Examples describe the preparation of 21,31-O-isopropylidene - inosine, 21,31 - O - isopropylidene - adenosine, 21,31 - O - isopropylidene - guanosine, 21,31 - O - isobutylidene - inosine, 21,31 - O - isobutylidene - adenosine and 21,31-O - (1,3 - dimethyl - butylidene) - inosine. |
