D-Eritadenine (Ia) and L-eritadenine (IIa) were prepared from 5-(adenin-9-yl)-5-deoxyaldofuranoses or enantiomeric 2,3-disubstituted erythronolactones (VIIIb, c, XIV). Oxidation of methyl 2,3-O-isopropylidene-D-ribofuranoside (IX) with periodate in the presence of ruthenium, followed by acid hydrolysis and reduction with sodium borohydride, afforded L-ribonolactone (XI). Its 2,3-O-isopropylidene derivative was subjected to alkaline hydrolysis, followed by oxidation with periodate, reduction with sodium borohydride and reaction with cyclohexanone to give 2,3-O-cyclohexylidene-L-erythronolactone (XIV). Condensation of [U-14C]-adenine with VIIIb, followed by acid hydrolysis, afforded [U-14C-adenine]-D-eritadenine. The threo-eritadenines III and IV were prepared by oxidation of 1-(adenin-9-yl)-1-deoxy-2,3-O-isopropylidenethreitols XVI and XVII with sodium periodate in the presence of ruthenium, followed by acid hydrolysis. Reaction of 9-(2,2-diethoxyethyl)adenine (XIX) with malonic acid gave 4-(adenin-9-yl)-3-butenoic acid (XXI); its methyl ester XXII, prepared by treatment with methanol, was isomerized with triethylamine to give methyl 4-(adenin-9-yl)-2-butenoate (XXIII). Hydroxylation of XXIII with osmium tetroxide afforded the racemic mixture of D- and L-threo-eritadenine (III+ IV). Eritadenines Ia and IIa were active against vaccinia, measles and vesicular stomatitis virus. Eritadenine Ia was also effective against reo- and parainfluenza virus. In general, the antiviral activity of the eritadenines decreased in the order D-erythro (Ia) > L-erythro (IIa) > D- and L-threo (III, IV).
D-厄利他呋喃核苷(Ia)和L-厄利他呋喃核苷(IIa)是从5-(腺嘌呤-9-基)-5-脱氧醛糖或对映异构的2,3-二取代的赤霉糖内酯(VIIIb, c, XIV)制备而成。使用高碘酸盐在钌的存在下氧化甲基2,3-O-异丙基-D-核糖呋喃苷(IX),随后进行酸水解和硼氢化钠还原,得到L-核糖内酮(XI)。将其2,3-O-异丙基衍生物经过碱水解,随后经过高碘酸盐氧化、硼氢化钠还原和与环己酮反应,得到2,3-O-环己基-L-赤霉糖内酯(XIV)。[U-14C]-腺嘌呤与VIIIb缩合,经过酸水解,得到[U-14C-腺嘌呤]-D-厄利他呋喃核苷。通过高碘酸盐在钌的存在下氧化1-(腺嘌呤-9-基)-1-脱氧-2,3-O-异丙基脱氢醇(XVI)和(XVII),得到threo-厄利他呋喃核苷III和IV。9-(2,2-二乙氧基乙基)腺嘌呤(XIX)与丙二酸反应,得到4-(腺嘌呤-9-基)-3-丁烯酸(XXI);经过甲醇处理制备其甲酯(XXII),再与三乙胺异构化,得到甲基4-(腺嘌呤-9-基)-2-丁烯酸酯(XXIII)。XXIII的羟化反应得到D-和L-厄利他呋喃核苷的外消旋混合物(III+IV)。厄利他呋喃核苷Ia和IIa对牛痘病毒、麻疹病毒和水疱性口炎病毒具有活性。厄利他呋喃核苷Ia也对副流感病毒和副流感病毒有效。总体而言,厄利他呋喃核苷的抗病毒活性按照D-赤霉糖(Ia) > L-赤霉糖(IIa) > D-和L-threo(III, IV)的顺序递减。