Publications

These data indicate that ST-246 is a potent anti-orthopoxvirus compound; the mode of inhibition is dependent on the virus and cell type.

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The synthesis of phenyl-substituted and benzoannulated cycloSal phosphate triesters of the nucleoside analogue 2',3'-dideoxy-2',3'-didehydrothymidine (d4T, Zerit) as lipophilic, membrane-soluble pronucleotides is described. The cycloSal moiety was introduced by using cyclic chlorophosphite agents prepared from phenyl-substituted saligenin derivatives and ortho-hydroxymethylated naphthols, respectively. Hydrolysis studies (HPLC analysis) of the triesters 2, 3 showed a range of hydrolytic stability from 1.4 h up to 5.1 h and the stability could be correlated with the substitution pattern in the cycloSal moiety. A slight decrease of their stability was observed, if phenyl-substituted derivatives were hydrolyzed in human CEM/O cell extracts. D4T and thymine, possible products of enzymatic cleavage of the pronucleotides, were not detected in the cell extracts. A further investigation of the hydrolysis process was performed by 31P-NMR spectroscopy. This technique allowed a precise monitoring of the degradation products and the exact determination of the product ratio. Finally, the newly synthesized compounds were tested concerning their antiviral activity against HIV in vitro. A strong correlation of the hydrolysis properties and the antiviral activity was found. 3-phenyl-cycloSal-d4TMP showed a threefold increase in its anti-HIV-1 activity and retained full activity in thymidine kinase (TK) deficient cells, indicative of a successful TK-bypass.

The potencies of several alkoxyalkyl esters of acyclic nucleoside phosphonates against vaccinia virus and cowpox virus were evaluated in cell monolayers and three-dimensional epithelial raft cultures. Prodrugs were at least 20-fold more active than their parent compounds. Octadecycloxyethyl-(S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine emerged as the most potent derivative.

Various acyclic, i.e., (2-hydroxyethoxy)methyl and (2-acetoxyethoxy)methyl, analogues of pyrimidine and purine nucleosides have been prepared and evaluated for their antiviral, antimetabolic, and cytotoxic properties. All of the pyrimidine analogues, including (E)-5-(2-bromovinyl)-1-[(2-hydroxyethoxy)methyl]uracil (12) and its O-acetyl derivative (13), were virtually devoid of antiviral, cytotoxic, and antimetabolic activities. However, several of the 8-substituted derivatives of 9-[(2-hydroxyethoxy)methyl]guanine (acyclovir) had higher antiviral specificity in vitro than the parent drug. The 8-methyl-, 8-amino-, 8-bromo-, and 8-iodoacyclovir derivatives have activities worthy of further investigation.

Abstract Self-complementary dodecanucleotides containing BVDU (1) have been prepared by solid-phase synthesis employing the phosphoramidite technique. The phosphoramidite of BVDU was obtained after 4, 4′-dimethoxytritylation and subsequent phosphitylation of the nucleoside 1. Melting experiments of the dodecamers containing one BVDU residue showed that the stability of such duplexes is only slightly affected by the bulky bromovinyl residue. The dodecamers d(GTAGAAbv5UTCTAC) (9) and d(GTAGAATbv5UCTAC) (10) were subject to hydrolysis experiments with the endodeoxyribonuclease Eco RI under star activity conditions. Whereas regioselective hydrolysis was decreased in case of the oligomer 10, compared to the non-modified oligomer 8, the oligomer 9-was not hydrolyzed at all under these conditions. This can be explained by a steric interference of the bulky bromovinyl substituent with the nitrogen-7 of the adjacent adenine moiety being a proton acceptor site during endonuclease binding. A complete assignment of 1H and 13C NMR spectra of BVDU (1) is also reported.

As a continuation of previous studies on the synthesis and antitumor activity of geiparvarin analogues bearing a carbamate moiety in the alkyl side chain, a series of N-substituted [(E)-3-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)-2- butenyl]carbamates (15a-f) were synthesized and tested with the objective to investigate the reason for the marked difference of cytostatic activity found between alkyl and phenyl derivatives. A series of compounds, characterized by different physicochemical properties, were designed in order to study this hypothesis. Moreover, to further investigate the modification of the alkenyl side chain, (E)- and (Z)-[2-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)propenyl]-7H-furo[3,2- g][1]benzopyran-7-one (11a,b) were synthesized, the latter compounds being the combination of two units, namely, the 3(2H)-furanone ring system endowed with potent alkylating properties and the furocoumarin portion which binds to DNA resulting in potential DNA-targeted alkylating agents. The compounds were tested for their cytostatic activity against proliferation of murine (L1210) and human (Molt/4, CEM, or MT-4) tumor cells. The highest cytostatic activity found within both series of carbamic derivatives (15a-d,k and 15e,g-j) was associated with the highest global lipophilicity. With regard to compounds 11a,b, the cytostatic activity of (Z)-furocoumarin 11b might be related to a specific interaction with DNA (i.e., intercalation).