title: Synthesis and antiviral activity of (Z)- and (E)-2,2-[bis(hydroxymethyl)cyclopropylidene]methylpurines and -pyrimidines: second-generation methylenecyclopropane analogues of nucleosides.
abstract: The second generation of methylenecyclopropane analogues of nucleosides 5a-5i and 6a-6i was synthesized and evaluated for antiviral activity. The 2,2-bis(hydroxymethyl)methylenecyclopropane (11) was converted to dibromo derivative 7 via acetate 12. Alkylation-elimination of adenine (16) with 7 afforded the Z/E mixture of acetates 17 + 18, which was deacetylated to give analogues 5a and 6a separated by chromatography. A similar reaction with 2-amino-6-chloropurine (19) afforded acetates 20 + 21 and, after deprotection and separation, isomers 5f and 6f. The latter served as starting materials for synthesis of analogues 5b, 5e, 5g-5i and 6b, 6e, 6g-6i. Alkylation-elimination of N(4)-acetylcytosine (22) with 7 afforded a mixture of isomers 5c + 6c which were separated via N(4)-benzoyl derivatives 23 and 24. Deprotection furnished analogues 5c and 6c. Alkylation of 2,4-bis(trimethylsilyloxy)-5-methylpyrimidine (25) with 7 led to bromo derivative 26. Elimination of HBr followed by deacetylation and separation gave thymine analogues 5d and 6d. The guanine Z-isomer 5b was the most effective against human and murine cytomegalovirus (HCMV and MCMV) with EC(50) = 0.27-0.49 microM and no cytotoxicity. The 6-methoxy analogue 5g was also active (EC(50) = 2.0-3.5 microM) whereas adenine Z-isomer 5a was less potent (EC(50) = 3.6-11.7 microM). Cytosine analogue 5c was moderately effective, but 2-amino-6-cyclopropylamino derivative 5e was inactive. All E-isomers were devoid of anti-CMV activity, and none of the analogues was significantly active against herpes simplex viruses (HSV-1 or HSV-2). The potency against Epstein-Barr virus (EBV) was assay-dependent. In Daudi cells, the E-isomers of 2-amino-6-cyclopropylamino- and 2,6-diaminopurine derivatives 6e and 6h were the most potent (EC(50) approximately 0.3 microM), whereas only the thymine Z-isomer 5d was active (EC(50) = 4.6 microM). Guanine Z-derivative 5b was the most effective compound in H-1 cells (EC(50) = 7 microM). In the Z-series, the 2-amino-6-methoxypurine analogue 5g was the most effective against varicella zoster virus (VZV, EC(50) = 3.3 microM) and 2,6-diaminopurine 5h against hepatitis B virus (HBV, EC(50) = 4 microM). Adenine analogues 5a and 6a were moderately active as substrates for adenosine deaminase.
authors.affiliation: Department of Chemistry, Developmental Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan 48201-1379, USA.
authors.forename: Shaoman
authors.initials: S
authors.lastname: Zhou
authors.forename: Julie M
authors.initials: JM
authors.lastname: Breitenbach
authors.forename: Katherine Z
authors.initials: KZ
authors.lastname: Borysko
authors.forename: John C
authors.initials: JC
authors.lastname: Drach
authors.forename: Earl R
authors.initials: ER
authors.lastname: Kern
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Gullen
authors.forename: Yung-Chi
authors.initials: YC
authors.lastname: Cheng
authors.forename: Jiri
authors.initials: J
authors.lastname: Zemlicka
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D003521:Cyclopropanes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D003587:Cytomegalovirus / Q000187:drug effects; D015497:HIV-1 / Q000187:drug effects; D006515:Hepatitis B virus / Q000187:drug effects; D014645:Herpesvirus 3, Human / Q000187:drug effects; D004854:Herpesvirus 4, Human / Q000187:drug effects; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D009705:Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011687:Purines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D018139:Simplexvirus / Q000187:drug effects; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D003521:Cyclopropanes; D009705:Nucleosides; D011687:Purines; D011743:Pyrimidines