[d4U]-Spacer-[HI-236] double-drug inhibitors of HIV-1 reverse-transcriptase Original Research Article

[d4U]-Spacer-[HI-236] double-drug inhibitors of HIV-1 reverse-transcriptase Original Research Article Pages 4661-4673 Yassir Younis, Roger Hunter, Clare I. Muhanji, Ian Hale, Rajinder Singh, Christopher M. Bailey, Todd J. Sullivan, Karen S. Anderson Close preview | | Supplementary content Related articles | Related reference work articles Abstract | Figures/Tables | References Abstract Four double-drug HIV NRTI/NNRTI inhibitors 15a–d of the type [d4U]-spacer-[HI-236] in which the spacer is varied as 1-butynyl (15a), propargyl-1-PEG (15b), propargyl-2-PEG (15c) and propargyl-4-PEG (15d) have been synthesized and biologically evaluated as RT inhibitors against HIV-1. The key step in their synthesis involved a Sonogashira coupling of 5-iodo d4U’s benzoate with an alkynylated tethered HI-236 precursor followed by introduction of the HI-236 thiourea functionality. Biological evaluation in both cell-culture (MT-2 cells) as well as using an in vitro RT assay revealed 15a–c to be all more active than d4T. However, overall the results indicate the derivatives are acting as chain-extended NNRTIs in which for 15b–d the nucleoside component is likely situated outside of the pocket but with no evidence for any synergistic double binding between the NRTI and NNRTI sites. This is attributed, in part, to the lack of phosphorylation of the nucleoside component of the double-drug as a result of kinase recognition failure, which is not improved upon with the phosphoramidate of 15d incorporating a 4-PEG spacer. Article Outline 1. Introduction 2. Double-drug design aspects 3. Chemistry 4. Biological results and discussion 5. Experimental 5.1. General procedures for synthesis 5.2. Synthesis of intermediates for the coupling partners 7 and 11 5.2.1. N-[2-(2-Benzyloxy-5-methoxyphenyl)ethyl]-tert-butylcarbamate 3 5.2.2. N-[2-(2-Hydroxy-5-methoxyphenyl)ethyl]-tert-butylcarbamate 4 5.2.3. N-[2-(2-(5-Benzyloxy-3-oxapent-1-yloxy)-5-methoxyphenyl)ethyl]-tert-butylcarbamate 5b 5.2.4. N-[2-(2-(11-Benzyloxy-3,6.9-trioxaundec-1-yloxy)-5-methoxyphenyl)ethyl]-tert-butylcarbamate 5c 5.2.5. N-[2-(2-(11-p-Toluenesulphonyloxy-3,6.9-trioxaundec-1-yloxy)-5-methoxyphenyl)ethyl]-tert-butylcarbamate 6c 5.2.6. N-[2-(2-(3-Butynyl-1-oxy)-5-methoxyphenyl)ethyl]-tert-butylcarbamate 7a16 5.2.7. N-[2-(2-(11-Propargyloxy-3,6.9-trioxaundec-1-yloxy)-5-methoxyphenyl)ethyl]-tert-butylcarbamate 7d 5.2.8. 5′-Benzoyl-5-iodo-d4U 11 5.3. General procedure for Sonogashira coupling for compounds 7a–c to afford 12a–c 5.3.1. 5-{4-[2-(2-tert-Butoxycarbonylaminoethyl)-4-methoxyphenoxy]but-1-ynyl}-5′-O-benzoyl-2′,3′-didehydro-2′,3′-dideoxyuridine 12a 5.3.2. 5-{6-[2-(2-tert-Butoxycarbonylaminoethyl)-4-methoxyphenoxy]hexa-4-oxa-1-ynyl}-5′-O-benzoyl-2′, 3′-didehydro-2′, 3′-dideoxyuridine 12b 5.3.3. 5-{9-[2-(2-tert-Butoxycarbonylaminoethyl)-4-methoxyphenoxy]nona-4,7-dioxa-1-ynyl}-5′-O-benzoyl-2′, 3′-didehydro-2′, 3′-dideoxyuridine 12c 5.4. General procedure for the synthesis of thioureas 14a–d 5.4.1. 5-{4-[2-(2-(5-Bromo-2-pyridinyl)aminothiocarbonylamino)ethyl)-4-methoxyphenoxy]but-1-ynyl}-5′-O-benzoyl-2′,3′-didehydro-2′,3′-dideoxyuridine 14a 5.4.2. 5-{6-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]hexa-4-oxa-1-ynyl}-5′-O-benzoyl-2′,3′-didehydro-2′,3′-dideoxyuridine 14b 5.4.3. 5-{9-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]nona-4,7-dioxa-1-ynyl}-5′-O-benzoyl-2′,3′-didehydro-2′,3′-dideoxyuridine 14c 5.4.4. 5-{15-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]pentadeca-4,7,10,13-tetraoxa-1-ynyl}-5′-O-benzoyl-2′,3′-didehydro-2′,3′-dideoxyuridine 14d 5.5. General procedure for benzoate deprotection of 14a–d to afford 15a–d 5.5.1. 5-{4-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]but-1-ynyl}-2′,3′-didehydro-2′,3′-dideoxyuridine 15a16 5.5.2. 5-{6-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]hexa-4-oxa-1-ynyl}-2′,3′-didehydro-2′,3′-dideoxyuridine 15b 5.5.3. 5-{9-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]nona-4,7-dioxa-1-ynyl}-2′,3′-didehydro-2′,3′-dideoxyuridine 15c 5.5.4. 5-{15-[2-(2-(5-Bromo-2-pyridinylamino thiocarbonylamino)ethyl)-4-methoxyphenoxy]pentadeca-4,7,10,13-tetraoxa-1-ynyl}-2′,3′-didehydro-2′,3′-dideoxyuridine 15d 5.6. 2′,3′-Didehydro-2′,3′-dideoxy-5-iodouridine (5-iodo-d4U) 5.7. 2′,3′-Didehydro-2′,3′-dideoxy-5-iodouridine-5′-[p-tolylmethoxyalaninyl phosphate] 16 5.8. 5-{15-[2-(2-(5-Bromo-2-pyridinylaminothiocarbonylamino)ethyl)-4-methoxyphenoxy]pentadeca-4,7,10,13-tetraoxa-1-ynyl}-2′,3-didehydro-2′,3′-dideoxy-5-iodouridine-5′-5′-(p-methylphenyl methoxyalaninyl phosphate)-2′,3′-didehydro-2′,3′-dideoxyuridine 17 5.9. Anti-HIV evaluation 5.9.1. Steady-state IC50 determination Acknowledgments . Supplementary data References and notes