(1R*,4R*,7S*)-7-Aminobicyclo[2.2.1]hept-5-ene-2,2-dimethanol (15) was prepared in four easy steps from bicyclo[2.2.1]hept-5-ene-2,2-dimethanol (10). Reaction of amine 15 with ethyl N-((E)-3-ethoxymethacryloyl)carbamate afforded thymine derivatives 17a. The amine 15 was used to construct 6-chloro-9H-purine derivative 19a, 2-amino-6-chloro-9H-purine derivative 22a. Ammonolysis of 19a led to the adenine derivative 20a. Treatment of 22a with trifluoroacetic acid afforded guanine nucleoside 23a. (1R*,4R*,7S*)-7-[6-(Cyclopropylamino)-9H-purin-9-yl]bicyclo[2.2.1]hept-5-ene-2,2-dimethanol (21a) and (1R*,4R*,7S*)-7-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]bicyclo[2.2.1]hept-5-ene-2,2-dimethanol (24a) were prepared by aminolysis of 19a and 22a. Saturated nucleosides 17b, 20b, 21b, 23b, 24b were obtained by hydrogenation on palladium catalyst.
(1R*,4R*,7S*)-7-氨基双环[2.2.1]庚-5-烯-2,2-二甲醇(15)通过四个简单步骤从双环[2.2.1]庚-5-烯-2,2-二甲醇(10)制备而成。氨基15与乙基N-((E)-3-乙氧甲基丙烯酰)氨基甲酸酯反应生成胸腺嘧啶衍生物17a。氨基15用于构建6-氯-9H-嘌呤衍生物19a、2-氨基-6-氯-9H-嘌呤衍生物22a。氨解19a导致腺嘌呤衍生物20a。用三氟乙酸处理22a得到鸟嘌呤核苷23a。(1R*,4R*,7S*)-7-[6-(环丙基氨基)-9H-嘌呤-9-yl]双环[2.2.1]庚-5-烯-2,2-二甲醇(21a)和(1R*,4R*,7S*)-7-[2-氨基-6-(环丙基氨基)-9H-嘌呤-9-yl]双环[2.2.1]庚-5-烯-2,2-二甲醇(24a)通过氨解19a和22a制备。在钯催化剂上氢化得到饱和核苷17b、20b、21b、23b、24b。