反应详情

As shown in Scheme 4, alkylation of adenine 10 with 3-bromopropionitrile in the presence of NaH in DMF gave N9-(cyanoethyl)adenine 15 in 75% yield. Reaction of 15 with methyl iodoacetate and lithium 2,2,6,6-tetramethylpiperidine (Li TMP) in THF afforded a mixture of N7-alkylated product 16 (60% yield) and N9-isomer 17 (20% yield). Reduction of the ester group in 16 with NaBH4 in wet THF13 gave N7-(hydroxyethyl)adenine 18 in 55% yield. Conversion of 18 to phosphonate 19 (60% yield) was accomplished by use of diethyl (p-toluenesulfonyloxymethane)phosphonate and sodium tert-butoxide in DMF.14 Treatment of compound 19 with Me3SiBr15 then afforded phosphonic acid 20 in 45% yield.