Nonpeptidic potent HIV-1 protease inhibitors: (4-hydroxy-6-phenyl-2-oxo-2H- pyran-3-yl)thiomethanes that span P1-P2' subsites in a unique mode of active site binding.
Using molecular modeling and the information derived from the X-ray crystal structure of HIV-1 protease (HIV PR) complexed with the pyran-2-one 1, a series of (4-hydroxy-6-phenyl-2-oxo-2H-pyran-3-yl)thiomethanes was designed and analyzed as novel, nonpeptidic inhibitors of HIV PR. Structure-activity studies led to the discovery of inhibitor 19 having (RS)-1-(cyclopentylthio)-3-methylbutyl functionalization at the C-3 position, which exhibited a Kc of 33 nM. A X-ray crystallographic structure of 19 bound to HIV PR showed that structural water-301 (inhibitor-flap-bridging water) was displaced by the inhibitor. Interestingly, the enol moiety of the pyran-2-one formed a hydrogen bond directly with Asp125 and with Asp25 via a bridging water molecule, thus illustrating a unique mode of active site binding by an HIV PR inhibitor. The pendant cyclopentyl and isobutyl groups of 19 occupied the S1' and S2' binding sites, respectively, whereas the 6-phenyl group occupied a region in between the S1 and S3 pockets of HIV PR. Selected compounds were tested for antiviral activity on H9 cells infected with HIV-1IIIb. A correlation between enzymatic activity and antiviral activity was not found in this series. The best antiviral compound in this series, 18, contained (RS)-3-[cyclopentyl(cyclopentylthio)methyl] functionalization at the C-3 position of the pyran-2-one ring and exhibited a CIC50 of 14 microM and TC50 of 70 microM. These studies demonstrate that potent enzyme inhibition can be achieved by inhibitors that span only three subsites.
Prasad
J V
JV
Department of Chemistry, Parke-Davis Pharmaceutical Research Division, Warner-Lambert Company, Ann Arbor, Michigan 48106, USA.
Para
K S
KS
Tummino
P J
PJ
Ferguson
D
D
McQuade
T J
TJ
Lunney
E A
EA
Rapundalo
S T
ST
Batley
B L
BL
Hingorani
G
G
Domagala
J M
JM
D000595:Amino Acid Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D002478:Cells, Cultured; D018360:Crystallography, X-Ray; D017320:HIV Protease Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011753:Pyrones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship
D017320:HIV Protease Inhibitors; D011753:Pyrones