Design, synthesis, and biological evaluation of (2R,alphaS)-3,4-dihydro-2-[3-(1,1,2,2-tetrafluoroethoxy)phenyl]-5-[3-(trifluoromethoxy)-phenyl]-alpha-(trifluoromethyl)-1(2H)-quinolineethanol as potent and orally active cholesteryl ester transfer protein inhibitor

Electrochemical heterodifunctionalization of α-CF3 alkenes to access α-trifluoromethyl-β-sulfonyl tertiary alcohols

An unprecedented electrochemical heterodifunctionalization of α-CF₃ alkenes with benzenesulfonyl hydrazides was accomplished in this work, wherein a β-sulfonyl and a α-hydroxyl group were simultaneously incorporated across the olefinic double bond in a single operation. Consequently, a series of potentially medicinally valuable and densely functionalized α-trifluoromethyl-β-sulfonyl tertiary alcohols were assembled under mild conditions. Electrochemically-driven oxidative 1,2-difunctionlization of electron-deficient alkenes well obviates the need for oxidizing reagents, thus rendering this protocol more eco-friendly.

Copper-catalysed enantioselective Michael addition of malonic esters to β-trifluoromethyl-α,β-unsaturated imines

A diastereo- and enantioselective Michael addition of methyl malonate to β-trifluoromethyl unsaturated imines is presented.

Discovery of Novel Indoline Cholesterol Ester Transfer Protein Inhibitors (CETP) through a Structure-Guided Approach

Using the collective body of known (CETP) inhibitors as inspiration for design, a structurally novel series of tetrahydroquinoxaline CETP inhibitors were discovered. An exemplar from this series, compound 5, displayed potent in vitro CETP inhibition and was efficacious in a transgenic cynomologus-CETP mouse HDL PD (pharmacodynamic) assay. However, an undesirable metabolic profile and chemical instability hampered further development of the series. A three-dimensional structure of tetrahydroquinoxaline inhibitor 6 was proposed from (1)H NMR structural studies, and this model was then used in silico for the design of a new class of compounds based upon an indoline scaffold. This work resulted in the discovery of compound 7, which displayed potent in vitro CETP inhibition, a favorable PK-PD profile relative to tetrahydroquinoxaline 5, and dose-dependent efficacy in the transgenic cynomologus-CETP mouse HDL PD assay.

An enantioselective approach to 2-alkyl substituted tetrahydroquinolines: total synthesis of (+)-angustureine

A simple and highly efficient synthetic approach to enantiopure 2-alkyl substituted tetrahydroquinoline 1 skeleton from aldehydes as starting materials and its application to the total synthesis of (+)-angustureine 2 is described.

Catalytic asymmetric conjugate addition of terminal alkynes to β-trifluoromethyl α,β-enones

The first enantioselective conjugate alkynylation of β-trifluoromethyl α,β-enones using terminal alkynes and a taniaphos–Cu(i) complex as catalyst is described.

Cardiovascular disease risk reduction by raising HDL cholesterol--current therapies and future opportunities

Since the first discovery of an inverse correlation between high-density lipoprotein-cholesterol (HDL-C) levels and coronary heart disease in the 1950s the life cycle of HDL, its role in atherosclerosis and the therapeutic modification of HDL-C levels have been major research topics. The Framingham study and others that followed could show that HDL-C is an independent cardiovascular risk factor and that the increase of HDL-C of only 10 mg·L(-1) leads to a risk reduction of 2-3%. While statin therapy and therefore low-density lipoprotein-cholesterol (LDL-C) reduction could lower coronary heart disease considerably; cardiovascular morbidity and mortality still occur in a significant portion of subjects already receiving therapy. Therefore, new strategies and therapies are needed to further reduce the risk. Raising HDL-C was thought to achieve this goal. However, established drug therapies resulting in substantial HDL-C increase are scarce and their effect is controversial. Furthermore, it is becoming increasingly evident that HDL particle functionality is at least as important as HDL-C levels since HDL particles not only promote reverse cholesterol transport from the periphery (mainly macrophages) to the liver but also exert pleiotropic effects on inflammation, haemostasis and apoptosis. This review deals with the biology of HDL particles, the established and future therapeutic options to increase HDL-C and discusses the results and conclusions of the most important studies published in the last years. Finally, an outlook on future diagnostic tools and therapeutic opportunities regarding coronary artery disease is given.

Prediction of a potentially effective dose in humans for BAY 60-5521, a potent inhibitor of cholesteryl ester transfer protein (CETP) by allometric species scaling and combined pharmacodynamic and physiologically-based pharmacokinetic modelling

AIMS

The purpose of this work was to support the prediction of a potentially effective dose for the CETP-inhibitor, BAY 60-5521, in humans.

METHODS

A combination of allometric scaling of the pharmacokinetics of the CETP-inhibitor BAY 60-5521 with pharmacodynamic studies in CETP-transgenic mice and in human plasma with physiologically-based pharmacokinetic (PBPK) modelling was used to support the selection of the first-in-man dose.

RESULTS

The PBPK approach predicts a greater extent of distribution for BAY 60-5521 in humans compared with the allometric scaling method as reflected by a larger predicted volume of distribution and longer elimination half-life. The combined approach led to an estimate of a potentially effective dose for BAY 60-5521 of 51 mg in humans.

CONCLUSION

The approach described in this paper supported the prediction of a potentially effective dose for the CETP-inhibitor BAY 60-5521 in humans. Confirmation of the dose estimate was obtained in a first-in-man study.

Single dose pharmacokinetics, pharmacodynamics, tolerability and safety of BAY 60-5521, a potent inhibitor of cholesteryl ester transfer protein

AIMS

To determine pharmacokinetics (PK), pharmacodynamics (PD), tolerability and safety of BAY 60-5521, a potent inhibitor of cholesteryl ester transfer protein (CETP).

METHODS

The first in man (FIM) study investigated the safety, tolerability, pharmacodynamics and pharmacokinetics in healthy male subjects following administration of single oral doses. The study was performed using a randomized, single-blind, placebo-controlled, single dose-escalation design. Thirty-eight young healthy male subjects (aged 20-45 years) received an oral dose of 5, 12.5, 25 or 50 mg BAY 60-5521 (n= 28) or were treated with a placebo (n= 10).

RESULTS

In all four dose steps, only one adverse event (25 mg; mild skin rash) was considered drug related. Clinical laboratory parameters showed no clinically relevant changes. A clear dose-dependent CETP inhibition could be demonstrated starting at a dose of 5 mg. At a dose of 25 mg, a CETP inhibition >50% over 18 h was observed. After 50 mg, CETP inhibition >50% lasted more than 50 h. Twenty-four h after administration mean HDL-C-values showed a nearly dose-proportional increase. Following administration of 50 mg, a significant HDL-C increase of about 30% relative to baseline values was found. BAY 60-5521 was slowly absorbed reaching maximum concentrations in plasma after 4 to 6 h. The disposition in plasma was multi-exponential with an estimated mean terminal half-life of 76 to 144 h.

CONCLUSIONS

BAY 60-5521 was clinically safe and well tolerated. No effects on heart rate, blood pressure and ECG recordings were observed during the study. A clear pharmacodynamic effect on CETP inhibition and HDL could be demonstrated.

Design, synthesis and structure-activity-relationship of 1,5-tetrahydronaphthyridines as CETP inhibitors

This Letter describes the discovery and SAR optimization of 1,5-tetrahydronaphthyridines, a new class of potent CETP inhibitors. The effort led to the identification of 21b and 21d with in vitro human plasma CETP inhibitory activity in the nanomolar range (IC(50)=23 and 22nM, respectively). Both 21b and 21d exhibited robust HDL-c increase in hCETP/hApoA1 dual heterozygous mice model.

Torcetrapib produces endothelial dysfunction independent of cholesteryl ester transfer protein inhibition

OBJECTIVE

Torcetrapib, a prototype cholesteryl ester transfer protein (CETP) inhibitor with potential for decreasing atherosclerotic disease, increased cardiovascular events in clinical trials. The identified hypertensive and aldosterone-elevating actions of torcetrapib may not fully account for this elevated cardiovascular risk. Therefore, we evaluated the effects of torcetrapib on endothelial mediated vasodilation in vivo.

METHODS AND RESULTS

In vivo endothelial mediated vasodilation was assessed using ultrasound imaging of acetylcholine-induced changes in rabbit central ear artery diameter. Torcetrapib, in addition to producing hypertension and baseline vasoconstriction, markedly inhibited acetylcholine-induced vasodilation. A structurally distinct CETP inhibitor, JNJ-28545595, did not affect endothelial function despite producing similar degrees of CETP inhibition and high-density lipoprotein elevation. Nitroprusside normalized torcetrapib's basal vasoconstriction and elicited dose-dependent vasodilation of norepinephrine preconstricted arteries in torcetrapib-treated animals, indicating torcetrapib did not impair smooth muscle function.

CONCLUSIONS

Torcetrapib significantly impairs endothelial function in vivo, independent of CETP inhibition and high-density lipoprotein elevation. Given the well-documented association of endothelial dysfunction with cardiovascular disease and risk, this activity of torcetrapib may have contributed to increased cardiovascular risk in clinical trials.

Cholesteryl ester transfer protein and its inhibition

Cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that facilitates the transfer of cholesteryl esters from the atheroprotective high density lipoprotein (HDL) to the proatherogenic low density lipoprotein cholesterol (LDL) and very low density lipoprotein cholesterol (VLDL) leading to lower levels of HDL but raising the levels of proatherogenic LDL and VLDL. Inhibition of CETP is considered a potential approach to treat dyslipidemia. However, discussions regarding the role of CETP-mediated lipid transfer in the development of atherosclerosis and CETP inhibition as a potential strategy for prevention of atherosclerosis have been controversial. Although many animal studies support the hypothesis that inhibition of CETP activity may be beneficial, negative phase III studies on clinical endpoints with the CETP inhibitor torcetrapib challenged the future perspectives of CETP inhibitors as potential therapeutic agents. The review provides an update on current understanding of the molecular mechanisms involved in CETP activity and its inhibition.

Synthesis and discovery of 2,3-dihydro-3,8-diphenylbenzo[1,4]oxazines as a novel class of potent cholesteryl ester transfer protein inhibitors

2,3-Dihydro-3,8-diphenylbenzo[1,4]oxazines were identified as a new class of potent cholesteryl ester transfer protein inhibitors. The most potent compound 6a (IC50=26 nM) possessed a favorable pharmacokinetic profile with good oral bioavailability in rat (F=53%) and long human liver microsome stability (t(1/2)=62 min). It increased HDL-C in human CETP transgenic mice and high-fat fed hamsters. The structure and activity relationship of this series will be described in this Letter.