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Computer-aided Design, Synthesis, and anti-HIV-1 Activity in Vitro of 2-alkylamino-6-[1-(2,6-difluorophenyl)alkyl]-3,4-dihydro-5-alkylpyrimidin-4(3H)-ones as Novel Potent Non-Nucleoside Reverse Transcriptase Inhibitors, Also Active Against the Y181C Variant

Rino Ragno, Antonello Mai, Gianluca Sbardella, Marino Artico, Silvio Massa, Chiara Musiu, Massimo Mura, Flavia Marturana, Alessandra Cadeddu, Paolo La Colla

J Med Chem. 2004 Feb 12;47(4):928-34.

PMID: 14761194

Abstract:

Dihydro-alkoxy-benzyl-oxopyrimidines (DABOs) are a family of potent NNRTIs developed in the past decade. Attempts to improve their potency and selectivity led to thio-DABOs (S-DABOs), DATNOs, and difluoro-thio-DABOs (F(2)-S-DABOs). More recently, we reported the synthesis and molecular modeling studies of a novel conformationally constrained subtype of the S-DABO series characterized by the presence of substituents on the methylene linkage connecting the pyrimidine ring to the aryl moiety (Mai, A., et al. J. Med. Chem. 2001, 44, 2544-2554). Now we report the computer-aided design, synthesis, and biological evaluation of four new DABO prototypes (5-alkyl-2-cyclopentylamino-6-[1-(2,6-difluorophenyl)alkyl]-3,4-dihydropyrimidin-4(3H)-ones, F(2)-NH-DABOs) in which the sulfur atom of the related F(2)-S-DABOs is replaced by an amino group. For these studies, we used as a reference model the cocrystallized MKC-442/RT complex. Docking studies with Autodock of the newly designed F(2)-NH-DABOs on the ligand-derived RT confirmed the findings previously described for the F(2)-S-DABOs. The F(2)-NH-DABO binding mode resembles that reported for F(2)-S-DABOs, with the difference that the NH moiety at the C-2 position represents a new anchor site for ligand/enzyme complexation. The predicted inhibition constant (K(i)) values by the internal scoring function of Autodock, and the predicted IC(50) values by the application of a VALIDATE II/HIV-RT model strongly suggested the synthesis of the designed amino-DABOs. F(2)-NH-DABOs were shown to be highly active in both anti-RT and anti-HIV biological assays with IC(50) and EC(50) comparable with that of the reference compound MKC-442. Interestingly, 2-cyclopentylamino-6-[1-(2,6-difluorophenyl)ethyl]-3,4-dihydro-5-methyl pyrimidin-4(3H)-one (9d) was active against the Y181C HIV-1 mutant strain at submicromolar concentration, with a resistance value similar to that of efavirenz, the last FDA-approved NNRTI for AIDS therapy, and 2-fold lower than that of its 2-cyclopentylthio counterpart 8d. The introduction in 9d of a new anchor point (pyrimidine C-2 NH group), with the formation of a new hydrogen bond with Lys101, could compensate for the lack of positive hydrophobic ligand/NNBP interactions due to the Tyr181 to Cys181 mutation.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP391860734 Efavirenz Related Compound C Efavirenz Related Compound C 391860-73-4 Price
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