To study the effect of β-substitution in 2'-alkyl derivatives of 9-(2-phosphonomethoxyethyl)adenine (Ia) on the antiviral activity or group specificity, these derivatives were synthesized. 9-(2-Hydroxyalkyl)adenines VIII were prepared by alkylation of adenine with suitably substituted oxiranes XIII or 2-hydroxyalkyl p-toluenesulfonates IV and VI. After protection of the adenine amino group by benzoylation (compounds IX) or amidine formation (compounds X), the intermediates were alkylated with diisopropyl p-toluenesulfonyloxymethanephosphonate (XI) in the presence of sodium hydride. After deprotection, the obtained phosphonate diesters XII were converted into phosphonic acids I by transsilylation and hydrolysis. This synthetic scheme was used for the preparation of ethyl (Ie), propyl (If), 2-propyl (Ig), 2-methylpropyl (Ih), cyclopropyl (Ii), cyclohexyl (Ij), benzyl (Ik) and phenyl (Il) derivatives. The 2'-trifluoromethyl derivative XXIIa was prepared analogously from 9-(2-hydroxy-3,3,3-trifluoropropyl)adenine (XXa), obtained by alkylation of adenine sodium salt with 2-hydroxy-3,3,3-trifluoropropyl bromide. 2'-Trimethylsilyl derivative XIXa was obtained by alkylation of adenine with 2-diisopropylphosphonomethoxy-3-(4-toluenesulfonyloxy)propyltrimethylsilane (XVII) followed by transsilylation and hydrolysis of diester XVIIIa. 2,6-Diaminopurine derivatives XVIIId and XXIIb were obtained analogously. 9-(3-Phosphonomethoxybutyl)adenine (XXVIII) and 9-(2-methyl-2-phosphonomethoxypropyl)adenine (XXXV) were prepared from the corresponding hydroxy derivatives XXVIb and XXXII, respectively, by the same reaction pathway as derivatives I.
为了研究9-(2-磷酸甲氧基乙基)腺嘌呤(Ia)的2'-烷基衍生物中β-取代对抗病毒活性或基团特异性的影响,合成了这些衍生物。通过将腺嘌呤与适当取代的环氧烷(XIII)或2-羟基烷基对甲苯磺酸酯(IV和VI)烷基化制备了9-(2-羟基烷基)腺嘌呤(VIII)。在通过苯甲酰化(化合物IX)或酰胺化(化合物X)保护腺嘌呤氨基后,中间体在氢化钠存在下与二异丙基对甲苯磺酸氧甲基膦酸酯(XI)烷基化。去保护后,得到的膦酸二酯(XII)通过转硅烷化和水解转化为膦酸(I)。这种合成方案用于制备乙基(Ie)、丙基(If)、2-丙基(Ig)、2-甲基丙基(Ih)、环丙基(Ii)、环己基(Ij)、苄基(Ik)和苯基(Il)衍生物。2'-三氟甲基衍生物(XXIIa)类似地从9-(2-羟基-3,3,3-三氟丙基)腺嘌呤(XXa)制备,后者通过腺嘌呤钠盐与2-羟基-3,3,3-三氟丙基溴化物烷基化获得。2'-三甲基硅基衍生物(XIXa)通过腺嘌呤与2-二异丙基膦酸甲氧基-3-(4-对甲苯磺酰氧基)丙基三甲基硅烷(XVII)烷基化后,转硅烷化和水解膦酸二酯(XVIIIa)获得。2,6-二氨基嘌呤衍生物(XVIIId和XXIIb)类似地获得。9-(3-磷酸甲氧基丁基)腺嘌呤(XXVIII)和9-(2-甲基-2-磷酸甲氧基丙基)腺嘌呤(XXXV)分别从相应的羟基衍生物(XXVIb和XXXII)通过与衍生物I相同的反应途径制备。