The Discovery of GS-9131, an Amidate Prodrug of a Novel Nucleoside Phosphonate HIV Reverse Transcriptase Inhibitor - Accounts in Drug Discovery Case Studies in Medicinal Chemistry - page 229

30a Phe-Bu i OCH 2 CF 3 119 4100 4.05 30 107 84 91 27 - - -
30b Phe-Bu i OPh 6.0 38 4.86 29 655 84 52 28 - 8.3 -
30c Phe-Et OPh 33 25 4.05 39 246 78 74 37 78 - -
30d Ala-Bu n OPh 92 91 3.47 6183 100 89 63 - - -
30e Ala-Bu i OPh 58 4100 3.25 7916 93 81 38 86 - -
30f Ala-Pr n OPh 52 31 2.96 19 103 100 96 88 - - -
30g Ala-Et OPh 96 74 2.45 7280 84 88 165 189 146 318
30h Ala-cBu OPh 36 57 3.05 18 150 87 84 100 98 25 122
30i Ala-Pr i OPh 728 - 2.98 216 78 97 88 127 - -
a Values for active compounds are results of at least two experiments in MT-2 cells; standard deviation is given in parentheses. b Activity is represented as pmol
compound cleaved min 1 mg 1 of enzyme or extract. c Disoproxil (POC), phenylalanine (Phe), alanine (Ala), n-butyl (Bu n ), n-propyl (Pr n ), ethyl (Et), isobutyl (Bu i ),
isopropyl (Pr i ), cyclobutyl (cBu), phenol (OPh).

d A ¼ first eluting isomer; B ¼ second eluting isomer from chiral chromatography. e clog D was calculated using

f % prodrug remaining after 60min incubation.

Pallas 3.0 from CompuDrug International, Sedona, AZ.