RESUMO
Methyl-substituted cycloSal-pronucleotides of d4TMP were synthesized with high diastereoselectivities in satisfying chemical yields. The individual diastereomers were tested against HIV-1 and HIV-2 infected wild-type CEM/0 and HIV-2 infected thymidine kinase deficient CEM cells. All diastereomers tested showed significant antiviral activity in CEM/0 and strong activity in CEM/TK(-) cell cultures. The antiviral activities were strongly dependent on the chirality at the phosphate group and the position of the methyl-group(s) in the cycloSal moiety. In CEM/TK(-) cell cultures the difference in antiviral potency was found to be 7- to 20-fold. The stability of each diastereomer was studied in aqueous phosphate buffer and in CEM/0 cell extracts. Large differences in the half-lives were found. A comparison of the relative lipophilicity of the methyl-substituted cycloSal triesters was performed based on the retention times obtained by reversed phase HPLC. The results obtained clearly confirm the importance of a diastereoselective synthesis of cycloSal-pronucleotides.
Assuntos
Fármacos Anti-HIV/síntese química , Didesoxinucleotídeos/síntese química , Estavudina/análogos & derivados , Nucleotídeos de Timina/síntese química , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Linhagem Celular , Didesoxinucleotídeos/química , Didesoxinucleotídeos/farmacologia , Estabilidade de Medicamentos , HIV-1/efeitos dos fármacos , HIV-2/efeitos dos fármacos , Humanos , Hidrólise , Mutação , Solventes/química , Estavudina/síntese química , Estavudina/química , Estavudina/farmacologia , Estereoisomerismo , Relação Estrutura-Atividade , Timidina Quinase/genética , Nucleotídeos de Timina/química , Nucleotídeos de Timina/farmacologiaRESUMO
A diastereoselective synthesis of cycloSal-phosphotriesters (cycloSal=cycloSaligenyl) based on chiral auxiliaries has been developed that allows the synthesis of single diastereomers of the cycloSal-pronucleotides. In previously described synthesis routes, the cycloSal-compounds were always obtained as 1:1 diastereomeric mixtures that could be separated in only rare cases. However, it was shown that the diastereomers have different antiviral activity, toxicity, and hydrolysis stabilities. Here, first a chiral thiazoline derivative was used to prepare nonsubstituted and 5-methyl-cycloSal-phosphotriesters in 48 and ≥95% de (de=diastereomeric excess). However, this approach failed to give the important group of 3-substituted cycloSal-nucleotides. Therefore, two other chiral groups were discovered that allowed the synthesis of (R(P))- and (S(P))-3-methyl-cycloSal-phosphotriesters as well. The antiviral activity was found to be five- to 20-fold different between the two individual diastereomers, which proved the importance of this approach.