Design and synthesis of a new series of cyclopropylamino-linking diarylpyrimidines as HIV non-nucleoside reverse transcriptase inhibitors

Development of non-nucleoside reverse transcriptase inhibitors (NNRTIs): our past twenty years

Human immunodeficiency virus (HIV) is the primary infectious agent of acquired immunodeficiency syndrome (AIDS), and non-nucleoside reverse transcriptase inhibitors (NNRTIs) are the cornerstone of HIV treatment. In the last 20 years, our medicinal chemistry group has made great strides in developing several distinct novel NNRTIs, including 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), thio-dihydro-alkoxy-benzyl-oxopyrimidine (S-DABO), diaryltriazine (DATA), diarylpyrimidine (DAPY) analogues, and their hybrid derivatives. Application of integrated modern medicinal strategies, including structure-based drug design, fragment-based optimization, scaffold/fragment hopping, molecular/fragment hybridization, and bioisosterism, led to the development of several highly potent analogues for further evaluations. In this paper, we review the development of NNRTIs in the last two decades using the above optimization strategies, including their structure–activity relationships, molecular modeling, and their binding modes with HIV-1 reverse transcriptase (RT). Future directions and perspectives on the design and associated challenges are also discussed.

Synthesis and anti-human immunodeficiency virus activity of substituted ( o,o-difluorophenyl)-linked-pyrimidines as potent non-nucleoside reverse transcriptase inhibitors

With the worldwide number of human immunodeficiency virus positive patients stagnant and the increasing emergence of viral strains resistant to current treatment, the development of novel anti-human immunodeficiency virus drug candidates is a perpetual quest of medicinal chemists. Herein, we report a novel group of diarylpyrimidines, non-nucleoside reverse transcriptase inhibitors, which represents an important class of current anti-human immunodeficiency virus therapy. Series of diarylpyrimidines containing o,o-difluorophenyl (A-arm), 4-cyanophenylamino (B-arm), and a small substituent (e.g. NH₂, OMe) at positions 2, 4, and 6 of the pyrimidine ring were prepared. The A-arm was modified in the para position (F or OMe) and linked to the central pyrimidine core with a variable spacer (CO, O, NH). Antiviral activities of 20 compounds were measured against wild type human immunodeficiency virus-1 and mutant reverse transcriptase strains (K103N, Y181C) using a cytoprotection assay. To the most promising structural motives belong the o,o-difluoro-p-methoxy A-arm in position 4, and the amino group in position 6 of pyrimidine. Single digit nanomolar activities with no significant toxicity (CC₅₀ > 17,000 nM) were found for compounds 35 (EC₅₀ = 2 nM), 37 (EC₅₀ = 3 nM), and 13 (EC₅₀ = 4 nM) having O, NH, and CO linkers, respectively.

Discovery of biphenyl-substituted diarylpyrimidines as non-nucleoside reverse transcriptase inhibitors with high potency against wild-type and mutant HIV-1

A novel series of diarylpyrimidine (DAPY) derivatives bearing the biphenyl motif with multiple substituted groups was synthesized as human immunodeficiency virus (HIV)-1 non-nucleoside reverse transcriptase inhibitors. All of the target compounds were evaluated for their in vitro activity against HIV in MT-4 cells. Most of the compounds exhibited excellent activity with low nanomolar EC₅₀ values against wild-type, single and double mutant HIV-1 strains. Compound 4b displayed an EC₅₀ value of 1 nM against HIV-1 IIIB, 1.3 nM against L100I, 0.84 nM against K103 N, 1.5 nM against Y181C, 11 nM against Y188L, 2 nM against E138K, 10 nM against K103 N + Y181C, and almost 110 nM against F227L + V106. The improvement in the selectivity and potency of the target molecules against the wild-type and mutant HIV-1 strains validated our hypothesis. The biphenyl ring in the DAPY derivatives could strengthen the π-π stacking effect between the target molecule and the non-nucleoside inhibitor-binding pocket in the reverse transcriptase by extending the conjugating systems. This research represented a significant step toward the discovery of novel therapeutic DAPYs for treating acquired immunodeficiency syndrome in patients infected with HIV-1.