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The cardiovascular side effects associated with COX-2 selective drugs were the worst for coxibs leading to their withdrawal from the market a few years after their discovery. Therefore, the design of new series of pyrazole (4a,b 5a,b, 7a,b, 9a,b, 10a-h, and 11a-f) substituted with a triazole moiety as selective COX-2 inhibitors with cardioprotective effect was aimed in this paper. The target compounds were prepared and evaluated in-vitro against COX-1 and COX-2 enzymes. Compound 5-(5-Methyl-1-phenyl-1H-pyrazol-4-yl)-4H-1,2,4-triazole-3-thiol (7a) showed the highest selectivity towards COX-2 enzyme (S.I. = 27.56) and was the most active anti-inflammatory agent. Interestingly, its cardiovascular profile showed the cardiac biomarkers (ALP, AST, CK-MB, and LDH), as well as inflammatory cytokines named (TNF-α and IL-6) nearly similar to the control. Besides, a histopathological study of the heart muscle and the stomach was also included. The results confirmed that compound 7a has a more favorable cardio profile than celecoxib. Moreover, docking simulation for the most selective compounds 4b, 7a, 10e, 11c, and 11e inside COX-2 active site was performed to explain their binding mode. Finally, an ADME study was applied and proved the promising activity of the new compounds as a new oral anti-inflammatory agent. In conclusion, the newly developed compound 7a represents a potential selective COX-2 NSAID candidate with minimum cardiovascular risks., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Mitochondria play a key role for deciding fate of cells and thus are considered an attractive target for pharmacological interventions focused on containment of myocardial ischemia/reperfusion (I/R) injury. Notably, the activation of mitochondrial potassium (mitoK) channels produces a mild depolarization of mitochondrial membrane, that contributes to reduce the driving force to calcium uptake and prevents the formation of mitochondrial transition membrane pore (MPTP); these events underlie anti-ischemic cardioprotection. However, an ideal mitoK channel opener should possess the fundamental requirement to be delivered at mitochondrial level; therefore, to improve the mitochondrial delivery of a previously characterized spirocyclic benzopyrane F81, new compounds have been developed. The three original triphenylphosphonium (TPP + )-derivatives of F81 (1-3), were evaluated for their cardioprotective activity on both isolated cardiac mitochondria and cardiac H9c2 cell line. Compound 1 was further investigated in an in vivo infarct model. This work confirms that the TPP + strategy applied to mitoKATP openers could foster mitochondrial delivery and enhance the cardioprotective effects of mitochondrial activators of potassium channels., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Atherogenesis has been recognized as a risk factor for lethal cardiovascular diseases. Plasma low-density lipoprotein levels are correlated to the occurrence of atherosclerosis, and their control is critical for both the prevention and treatment of these diseases. Phospholipid transfer protein (PLTP) is one of the key regulators of lipoprotein metabolism; PLTP-deficient mice exhibit decreased apolipoprotein B (apoB)-containing lipoprotein secretion and atherosclerosis, indicating the validity of PLTP as a promising therapeutic target. Here, we demonstrate a high-throughput screening (HTS) method to identify a novel chemotype of PLTP inhibitors. Instead of using recombinant proteins, we used human plasma as a source of enzymes in the first screening, so as to efficiently exclude promiscuous inhibitors. The selected compounds were further confirmed to target PLTP both biochemically and biophysically and were shown to inhibit apoB secretion from hepatic cells with no apparent toxicity. We believe that our approach is suitable for filtering out nonspecific inhibitors at an earlier stage of screening campaigns and that these compounds should have potential to be developed into drugs to treat dyslipidemia.

The information obtained from crystallized complexes of the Na + ,K + -ATPase with cardiotonic steroids (CTS) is not sufficient to explain differences in the inhibitory properties of CTS such as stereoselectivity of CTS binding or effect of glycosylation on the preference to enzyme isoforms. The uncertainty is related to the spatial organization of the hydrophilic cavity at the entrance of the CTS-binding site. Therefore, there is a need to supplement the crystallographic description with data obtained in aqueous solution, where molecules have significant degree of flexibility. This work addresses the applicability of the electron paramagnetic resonance (EPR) method for the purpose. We have designed and synthesized spin-labeled compounds based on the cinobufagin steroid core. The length of the spacer arms between the steroid core and the nitroxide group determines the position of the reporting group (N-O) confined to the binding site. High affinity to Na + ,K + -ATPase is inferred from their ability to inhibit enzymatic activity. The differences between the EPR spectra in the absence and presence of high ouabain concentrations identify the signature peaks originating from the fraction of the spin labels bound within the ouabain site. The degree of perturbations of the EPR spectra depends on the length of the spacer arm. Docking of the compounds into the CTS site suggests which elements of the protein structure might be responsible for interference with the spin label (e.g., steric clashes or immobilization). Thus, the method is suitable for gathering information on the cavity leading to the CTS-binding site in Na + ,K + -ATPase in all conformations with high affinity to CTS., (© 2018 Federation of European Biochemical Societies.)

We previously identified AG-690/11026014 (6014) as a novel poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor that effectively prevented angiotensin II (Ang II)-induced cardiomyocyte hypertrophy. In the present study, we reported a new synthesis route for 6014, and investigated its protective effects on Ang II-induced cardiac remodeling and cardiac dysfunction and the underlying mechanisms in mice. We designed a new synthesis route to obtain a sufficient quantity of 6014 for this in vivo study. C57BL/6J mice were infused with Ang II and treated with 6014 (10, 30, 90 mg·kg -1 ·d -1 , ig) for 4 weeks. Then two-dimensional echocardiography was performed to assess the cardiac function and structure. Histological changes of the hearts were examined with HE staining and Masson's trichrome staining. The protein expression was evaluated by Western blot, immunohistochemistry and immunofluorescence assays. The activities of sirtuin-1 (SIRT-1) and the content of NAD+ were detected with the corresponding test kits. Treatment with 6014 dose-dependently improved cardiac function, including LVEF, CO and SV and reversed the changes of cardiac structure in Ang II-infused mice: it significantly ameliorated Ang II-induced cardiac hypertrophy evidenced by attenuating the enlargement of cardiomyocytes, decreased HW/BW and LVW/BW, and decreased expression of hypertrophic markers ANF, BNP and β-MHC; it also prevented Ang II-induced cardiac fibrosis, as implied by the decrease in excess accumulation of extracellular matrix (ECM) components collagen I, collagen III and FN. Further studies revealed that treatment with 6014 did not affect the expression levels of PARP-1, but dose-dependently inhibited the activity of PARP-1 and subsequently restored the activity of SIRT-1 in heart tissues due to the decreased consumption of NAD+ and attenuated Poly-ADP-ribosylation (PARylation) of SIRT-1. In conclusion, the novel PARP-1 inhibitor 6014 effectively protects mice against AngII-induced cardiac remodeling and improves cardiac function. Thus, 6014 might be a potential therapeutic agent for heart diseases..

Adenosine is an endogenous modulator exerting its functions through the activation of four adenosine receptor (AR) subtypes, termed A₁, A 2A , A 2B and A₃, which belong to the G protein-coupled receptor (GPCR) superfamily. The human A₃AR (hA₃AR) subtype is implicated in several cytoprotective functions. Therefore, hA₃AR modulators, and in particular agonists, are sought for their potential application as anti-inflammatory, anticancer, and cardioprotective agents. Structure-based molecular modeling techniques have been applied over the years to rationalize the structure-activity relationships (SARs) of newly emerged A₃AR ligands, guide the subsequent lead optimization, and interpret site-directed mutagenesis (SDM) data from a molecular perspective. In this review, we showcase selected modeling-based and guided strategies that were applied to elucidate the binding of agonists to the A₃AR and discuss the challenges associated with an accurate prediction of the receptor extracellular vestibule through homology modeling from the available X-ray templates.

In an attempt to search for more potent positive inotropic agents, two series of [1,2,4]triazolo[4,3- a ] quinoxaline derivatives bearing substituted benzylpiperazine and benzoylpiperazine moieties were synthesized and their positive inotropic activities evaluated by measuring left atrial stroke volume in isolated rabbit heart preparations. Several compounds showed favorable activities compared with the standard drug, milrinone. Compound 6c was the most potent agent, with an increased stroke volume of 12.53% ± 0.30% (milrinone: 2.46% ± 0.07%) at 3 × 10 -5 M. The chronotropic effects of compounds having considerable inotropic effects were also evaluated.

Myocardial ischemia is a primary cause of sudden death worldwide. Numerous active ingredients of traditional Chinese medicines including danshensu (DSS) and tetramethylpyrazine (TMP) have been widely used for the treatment of myocardial ischemia. To enhance their therapeutic efficacy and improve their drugability, in this work, we designed new DSS and TMP conjugates. Their water solubility and protective effects were studied in vitro and in experimental animal models. The new compounds demonstrated higher activities than the positive control agents acetylated danshensu and tetramethylpyrazine conjugate (ADTM) and salvianolic acid B (SAB) in preventing cells from oxidative insult. Among the new compounds, 14, bearing two glycine moieties, was more water soluble. In addition, compound 14 was much more potent in preventing cells from oxidative injury, at least 10- and 20-fold as potent as ADTM and SAB, respectively. The protective effects of compound 14 may be attributed to its anti-radical activity and anti-apoptotic activity. These results suggest that compound 14 is a promising candidate for the treatment of myocardial ischemia.

Apaf-1 is a central component in the apoptosis regulatory network for the treatment of apoptosis related diseases. Excessive Apaf-1 activity induced by myocardial ischemia causes cell injury. No drug targeted to Apaf-1 for treating myocardial ischemia has been reported to the best of our knowledge. In the present work, we synthesized a novel compound, ZYZ-488, which exhibited significant cardioprotective property in significantly increasing the viability of hypoxia-induced H9c2 cardiomyocytes and reducing CK and LDH leakage. Further study suggested the protective activity of ZYZ-488 dependent on its anti-apoptosis effect. This anti-apoptotic effect is most probably related to its disturbing the interaction between Apaf-1 and procaspase-9 as the target fishing and molecular docking indicated. The suppression on the activation of procaspase-9 and procaspase-3 with ZYZ-488 strongly suggested that compound ZYZ-488 could be a novel inhibitor of Apaf-1. In conclusion, ZYZ-488 as a novel small molecule competitive inhibitor of Apaf-1, with the great potential for treating cardiac ischemia.

Nowadays, there are some molecules that have shown over the years a high capacity to act against relevant pathologies such as cardiovascular disease, neurodegenerative disorders or cancer. This article provides a brief review about the origin, bioavailability and new research on curcumin and synthetized derivatives. It examines the beneficial effects on health, delving into aspects such as cancer, cardiovascular effects, metabolic syndrome, antioxidant capacity, anti-inflammatory properties, and neurological, liver and respiratory disorders. Thanks to all these activities, curcumin is positioned as an interesting nutraceutical. This is the reason why it has been subjected to several modifications in its structure and administration form that have permitted an increase in bioavailability and effectiveness against different diseases, decreasing the mortality and morbidity associated to these pathologies.

The potent positive inotropic effect, together with the relatively low safety risk of liguzinediol (LZDO), relative to currently available inotropic drugs, has prompted us to intensively research and develop LZDO as a potent positive inotropic agent. In this study, to obtain LZDO alternatives for oral chronic administration, a series of long-chain fatty carboxylic mono- and dual-esters of LZDO were synthesized, and preliminarily evaluated for physicochemical properties and bioconversion. Enhanced lipophilic properties and decreased solubility of the prodrugs were observed as the side chain length increased. All esters showed conspicuous chemical stability in phosphate buffer (pH 7.4). Moreover, the enzymatic hydrolysis of esters in human plasma and human liver microsomes confirmed that the majority of esters were converted to LZDO, with release profiles that varied due to the size and structure of the side chain. In vivo pharmacokinetic studies following oral administration of monopivaloyl (M5), monodecyl (M10) and monododecyl (M12) esters demonstrated the evidently extended half-lives relative to LZDO dosed alone. In particular the monopivaloyl ester M5 exhibited an optimal pharmacokinetic profile with appropriate physiochemical characteristics.

Objective: The biomechanical response to a myocardial infarction consists of ventricular remodeling that leads to dilatation, loss of contractile function, abnormal stress patterns, and ultimately heart failure. We hypothesized that intramyocardial injection of our previously designed pro-angiogenic chemokine, an engineered stromal cell-derived factor-1α analog (ESA), improves mechanical properties of the heart after infarction., Methods: Male rats (n = 54) underwent either sham surgery (n = 17) with no coronary artery ligation or ligation of the left anterior descending artery (n = 37). The rats in the myocardial infarction group were then randomized to receive either saline (0.1 mL, n = 18) or ESA (6 μg/kg, n = 19) injected into the myocardium at 4 predetermined spots around the border zone. Echocardiograms were performed preoperatively and before the terminal surgery. After 4 weeks, the hearts were explanted and longitudinally sectioned. Uniaxial tensile testing was completed using an Instron 5543 Microtester. Optical strain was evaluated using custom image acquisition software, Digi-Velpo, and analyzed in MATLAB., Results: Compared with the saline control group at 4 weeks, the ESA-injected hearts had a greater ejection fraction (71.8% ± 9.0% vs 55.3% ± 12.6%, P = .0004), smaller end-diastolic left ventricular internal dimension (0.686 ± 0.110 cm vs 0.763 ± 0.160 cm, P = .04), greater cardiac output (36 ± 11.6 mL/min vs 26.9 ± 7.3 mL/min, P = .05), and a lower tensile modulus (251 ± 56 kPa vs 301 ± 81 kPa, P = .04). The tensile modulus for the sham group was 195 ± 56 kPa, indicating ESA injection results in a less stiff ventricle., Conclusions: Direct injection of ESA alters the biomechanical response to myocardial infarction, improving the mechanical properties in the postinfarct heart., (Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

CGEN-856S is a novel Mas agonist. Herein, we examined the effects of this peptide on isoproterenol (ISO)-induced cardiac remodeling and myocardial infarction (MI) injury. We also sought to determine whether CGEN-856S activates the underlying mechanisms related to Mas receptor activation. Heart hypertrophy and fibrosis were induced by ISO (2 mg·kg(-1)·day(-1)) in Wistar rats. After a 7-day treatment period with CGEN-856S (90 µg·kg(-1)·day(-1)) or vehicle, the cardiomyocyte diameter was evaluated in left ventricular sections stained with hematoxylin and eosin, and immunofluorescence labeling and quantitative confocal microscopy were used to quantify the deposition of type I and III collagen and fibronectin in the left ventricles. MI was induced by coronary artery ligation, and CGEN-856S (90 µg·kg(-1)·day(-1)) or saline was administered for 14 days. The Langendorff technique was used to evaluate cardiac function, and left ventricular sections were stained with Masson's trichrome dye to quantify the infarct area. Using Chinese hamster ovary cells stably transfected with Mas cDNA, we evaluated whether CGEN-856S alters AKT and endothelial nitric oxide synthase (eNOS) phosphorylation. CGEN-856S reduced the degree of ISO-induced hypertrophy (13.91±0.17 µm vs. 12.41±0.16 µm in the ISO+CGEN-856S group). In addition, the Mas agonist attenuated the ISO-induced increase in collagen I, collagen III, and fibronectin deposition. CGEN-856S markedly attenuated the MI-induced decrease in systolic tension, as well as in +dT/dt and -dT/dt. Furthermore, CGEN-856S administration significantly decreased the infarct area (23.68±2.78% vs. 13.95±4.37% in the MI+CGEN-856S group). These effects likely involved the participation of AKT and NO, as CGEN-856S administration increased the levels of p-AKT and p-eNOS. Thus, our results indicate that CGEN-856S exerts cardioprotective effects on ISO-induced cardiac remodeling and MI-mediated heart failure in rats through a mechanism likely involving the eNOS/AKT pathway.

Aims: Inflammation and Toll-like receptor (TLR) signalling have been linked to the development of cardiac hypertrophy following transverse aortic constriction (TAC). In the present study, we investigated whether pre-treatment with the synthetic TLR9 ligands 1668-thioate or 1612-thioate modulates the progression of TAC-induced cardiac inflammation and hypertrophy., Methods and Results: C57BL/6N-mice were pre-treated with 1668-thioate, 1612-thioate (0.25 nmol/g, i.p.), or phosphate-buffered saline 16 h prior to TAC or sham surgery. Heart-weight/body-weight ratio (HW/BW), cardiomyocyte cell size, cellular macrophage accumulation, myofibroblast differentiation, and collagen deposition were investigated for up to 28 days. Cardiac function was monitored using a pressure-volume catheter and M-mode echocardiography. Inflammatory gene expression in the heart was analysed via gene array, while the time course of mRNA expression of key inflammatory mediators was assessed via RT-qPCR. TAC increased the HW/BW ratio and cardiomyocyte cell size and induced macrophage accumulation, myofibroblast differentiation, and collagen deposition. These changes were accompanied by cardiac inflammation and a significant loss of left ventricular function. Pre-treatment with cytosine-phosphate-guanine (CpG)-containing 1668-thioate attenuated the inflammatory response, the progression of cardiac hypertrophy, and cardiac remodelling, which resulted in a prolonged preservation of left ventricular function. These changes were induced to a smaller extent by the use of the non-CG-containing oligodeoxynucleotide 1612-thioate., Conclusion: Pre-treatment with 1668-thioate attenuated cardiac hypertrophy following pressure overload, possibly by modifying the hypertrophy-induced inflammatory response, thereby reducing cardiac growth and fibrosis as well as delaying loss of cardiac function.

Among the cardiotonics (agents against congestive heart failure), the most important group is of the digitalis cardiac glycosides, but since these compounds suffer from a low therapeutic index, attention has been paid to investigating safer cardiotonic agents through the inhibition of Na+,K(+)-ATPase, the mechanism by which the digitalis cardiac glycosides elicit their action. Recently, a series of perhydroindenes were studied for their Na+,K(+)-ATPase inhibition activity. We report here a QSAR study on them to investigate the physicochemical and structural properties of the molecules that govern their activity in order to rationalize the structural modification to have more potent drugs. A multiple regression analysis reveals a significant correlation between the Na+,K(+)-ATPase inhibition activity of the compounds and Kier's first order valence molecular connectivity index of their R5-substituents and some indicator parameters, suggesting that the R5-substituents of the compounds containing atoms with low valence and high saturation and the R1-substituents having =N-O- moiety will be conducive to the activity.

Objectives: Stromal cell-derived factor (SDF)-1α is a potent endogenous endothelial progenitor cell (EPC) chemokine and key angiogenic precursor. Recombinant SDF-1α has been demonstrated to improve neovasculogenesis and cardiac function after myocardial infarction (MI) but SDF-1α is a bulky protein with a short half-life. Small peptide analogs might provide translational advantages, including ease of synthesis, low manufacturing costs, and the potential to control delivery within tissues using engineered biomaterials. We hypothesized that a minimized peptide analog of SDF-1α, designed by splicing the N-terminus (activation and binding) and C-terminus (extracellular stabilization) with a truncated amino acid linker, would induce EPC migration and preserve ventricular function after MI., Methods: EPC migration was first determined in vitro using a Boyden chamber assay. For in vivo analysis, male rats (n = 48) underwent left anterior descending coronary artery ligation. At infarction, the rats were randomized into 4 groups and received peri-infarct intramyocardial injections of saline, 3 μg/kg of SDF-1α, 3 μg/kg of spliced SDF analog, or 6 μg/kg spliced SDF analog. After 4 weeks, the rats underwent closed chest pressure volume conductance catheter analysis., Results: EPCs showed significantly increased migration when placed in both a recombinant SDF-1α and spliced SDF analog gradient. The rats treated with spliced SDF analog at MI demonstrated a significant dose-dependent improvement in end-diastolic pressure, stroke volume, ejection fraction, cardiac output, and stroke work compared with the control rats., Conclusions: A spliced peptide analog of SDF-1α containing both the N- and C- termini of the native protein induced EPC migration, improved ventricular function after acute MI, and provided translational advantages compared with recombinant human SDF-1α., (Copyright © 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Selective PDE3 inhibitors improve cardiac contractility and may be used in congestive heart failure. However, their proarrhythmic potential is the most important side effect. In this research we designed, synthesized and evaluated the potential cardiotonic activity of thirteen PDE3 inhibitors (4-[(4-methyl-2-oxo-1,2-dihydro-6-quinolinyl)oxy]butanamide analogs) using the spontaneously beating atria model. The design strategy was based on the structure of cilostamide, a selective PDE3 inhibitor. In each experiment, atrium of reserpine-treated rat was isolated and the contractile and chronotropic effects of a synthetic compounds were assessed. All experiments were carried out in comparison with IBMX, amrinone and cilostamide as standard compounds. The results showed that, among the new compounds, the best pharmacological profile was obtained with the compound 6-[4-(4-methylpiperazine-1-yl)-4-oxobutoxy]-4-methylquinolin-2(1H)-one, 4j, which displayed selectivity for increasing the force of contraction (165 +/- 4% change over the control) rather than the frequency rate (115 +/- 7% change over the control) at 100 microM and potent inhibitory activity of PDE3 with IC(50) = 0.20 microM.

The use of anionic polycyclization was investigated in an effort to develop a versatile and convergent synthesis of advanced tetracyclic intermediates of batrachotoxin and ouabain analogues. Two new 5-(trialkylsilyl)-2-cyclohexenones as A ring precursors and a new Nazarov intermediate (D ring precursor) were prepared for this purpose. The reaction of the unsaturated beta-keto aldehyde A ring precursor with the enolate of the Nazarov intermediate afforded, after subsequent transformations, a 14-beta-hydroxysteroid with complete control of stereochemistry.

Aim: To study the effects of N-n-butyl haloperidol iodide (F2) on rat heart ischemia/reperfusion (I/R) injury and L-type calcium current (ICa) in rat ventricular myocytes., Methods: Rat heart I/R injury was induced by occluding the left anterior descending coronary artery for 30 min and restoring perfusion for 30 min. F2 (1, 2, and 4 mg/kg) were i.v. injected before ischemia. Plasma creatine kinase (CK), creatine kinase isoenzyme MB (CK-MB), lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (HBDH), glutamic-oxaloacetic transaminase (GOT), malondialdehyde (MDA) concentrations, and superoxide dismutase (SOD) activity were measured. The pathologic changes of I/R myocardium were assessed by the transmission electron microscopy. Single rat ventricular myocyte was obtained by enzymatic dissociation method. The currents were recorded with the whole-cell configuration of the patch-clamp technique., Results: F2 reduced the release of CK, CK-MB, LDH, HBDH and GOT, preserved the activity of SOD, and decreased the MDA contents dose-dependently. For morphology, F2 mollified the pathologic changes of myocardium induced by I/R injury. F2 1 micromol/L decreased ICa from (1775+/-360) pA to (464+/-129) pA (n=8, P<0.01) and shifted the current-voltage of ICa upward, without affecting the voltage-depend-ent properties of ICa., Conclusion: F2 played a protective role against rat heart I/R injury in a dose-dependent manner, and inhibited ICa in rat ventricular myocytes. The cardioprotective and vasodilatory mechanisms of F2 may be related to its inhibitory effect on L-type calcium channel.

Digitalis compounds are used in the treatment of congestive heart failure as positive inotropic agents; their action is mainly due to the inhibition of Na(+),K(+)-ATPase. A well-known drawback is their arrhythmogenic potential. Attempts to find safer digitalis-like compounds by means of molecular simplifications of the typical 5beta,14beta-steroidal skeleton, which appeared in the medicinal chemistry literature from 1990 until 2002, are briefly reviewed. Several novel achievements were obtained in order to better understand the requisites of the digitalis binding site on Na(+), K(+)-ATPase. Only minor simplification, such as cleavage of the D ring of the digitalis skeleton, could preserve the desired inotropic activity, while highly simplified digitalis-like compounds failed to give sufficiently high inotropic potency, even in the presence of a powerful pharmacophore, such as the O-aminoalkyloxime group.

Several novel hydroxylated cis-decalin derivatives, potential intermediates for the synthesis of the AB ring system of the important cardiotonic steroid ouabain, have been synthesized from commercially available starting materials. The first step in the preparation of these highly functionalized intermediates is a Robinson annulation of the beta-keto ester 6 and the 4-silyl-3-buten-2-one 5 to furnish the octalone 4 with good diastereoselectivity in fair yield (due to competition with a novel silicon-to-carbon phenyl migration). Reduction of the epoxy alcohol 3 (derived from 4 in two high-yielding steps) with LiAlH(4) gave a mixture of the desired triol 11 along with the product of an unusual reductive opening at the tertiary carbon, namely the triol 12. A plausible mechanism for this unusual reduction is presented as are possible methods for avoiding it. In particular, reduction of the corrresponding epoxy ketone 15 with aluminum amalgam proceeded in good yield to give the hydroxy ketone 16. Also reduction of the epoxide ester having the inverted stereochemistry at C3 afforded the desired tertiary alcohol 33 in good yield. Another approach using the beta,gamma-unsaturated ketal 38 permitted the formation of the tertiary alcohol 40. Fleming oxidation of the related, very functionalized silane 39 afforded the desired 1beta-alcohol 41 in fair yield. Finally a novel rearrangement was observed when the epoxy alcohol 24 was treated with DIBAL to effect loss of the angular hydroxymethyl group to produce the tetrasubstitued alkene 29 in high yield.

Novel 1,2,3,4-tetrahydroisoquinoline derivatives bearing directly a cyclic amine at the 2-position were prepared and examined for their bradycardic activities in isolated right atria and in anesthetized rats. The structure-activity relationships (SAR) study revealed that the 2-(3-piperidyl)-1,2,3,4-tetrahydroisoquinoline skeleton is essential for the appearance of potent in vitro activity, and that the presence of at least one methoxy group at the 6- or 7-position of the 1,2,3,4-tetrahydroisoquinoline ring is important to exert potent in vitro activity. In vivo tests of selected compounds demonstrated that 2-(1-benzyl-3-piperidyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (6c) exhibited potent bradycardic activity with negligible influence on mean blood pressure in rats, although its potency is a half of that of Zatebradine.

A series of 6-cyclic aliphatic amino-7-nitro-3,4-dihydroquinoline-2(1H)-ones were prepared and tested for platelet aggregation inhibitory effect, cardiotonic activity and chronotropic activity. These compounds appeared to show selective inhibitory activity against platelet aggregation. Among them, 6-(4-ethoxycarbonylpiperidino)-7-nitro-3,4-dihydroquinoline-2(1H)-one (22f) showed the most potent inhibitory activity and high selectivity. A divergent synthetic route to 6-cyclic aliphatic amino-7-nitro-3,4-dihydroquinoline-2(1H)-one derivatives has also been investigated.

Brief periods of cardiac ischemia trigger protection from subsequent prolonged ischemia (preconditioning). epsilon Protein kinase C (epsilonPKC) has been suggested to mediate preconditioning. Here, we describe an epsilonPKC-selective agonist octapeptide, psiepsilon receptor for activated C-kinase (psiepsilonRACK), derived from an epsilonPKC sequence homologous to its anchoring protein, epsilonRACK. Introduction of psiepsilonRACK into isolated cardiomyocytes, or its postnatal expression as a transgene in mouse hearts, increased epsilonPKC translocation and caused cardio-protection from ischemia without any deleterious effects. Our data demonstrate that epsilonPKC activation is required for protection from ischemic insult and suggest that small molecules that mimic this epsilonPKC agonist octapeptide provide a powerful therapeutic approach to protect hearts at risk for ischemia.

The enantiomers of 6-[3-(3,4-dimethoxybenzylamino)-2-hydroxypropoxy]-2(1H)-quinolinon e (OPC-18790), a novel cardiotonic agent, were synthesized and evaluated for positive inotropic activity. The key intermediates, 2,3-epoxypropoxy derivatives, were obtained by the alkylation of 6-hydroxy-2(1H)-quinolinone with optically active epichlorohydrin and subsequent ring closure. In an in vitro study, the (R)-(+)-isomer was about 10-fold more potent than the (S)-(-)-isomer.

Structure 1 is proposed for the Inagami-Tamura endogenous digitalis-like factor (EDLF), and (14 beta,17 alpha)-14-hydroxy- and (14 beta,17 alpha)-2,14-dihydroxyestradiols (2 and 3) were synthesized as models for studies on 1. The latter compound was remarkably potent in inducing a contractile response in isolated rat aorta and guinea pig left atrium.

Structures are proposed for the Inagami-Tamura endogenous digitalis-like factor (EDLF), and two possible candidates, (14 beta,15 beta,16 beta,17 alpha)- and (14 beta,15 alpha,16 alpha,17 alpha)-2,3,14,15,16,17-hexahydroxy-1,3,5(10)-estratrienes, were synthesized. Both compounds were potent in inducing a contractile response in isolated rat aorta and guinea pig left atrium.

A series of acyclic amide derivatives of N-(omega-aminoalkyl)-N-methylhomoveratrylamine was synthesized and evaluated for their bradycardic activity in isolated guinea pig right atria. Among these compounds, (E)-N-[3-[N'-[2-(3,4-dimethoxyphenyl)ethyl]-N'-methylamino]propyl]- 4-[3,4-(methylenedioxy)phenyl]-3-butenamide (35) was the most potent in vitro and was also found to show dose-dependent bradycardia without remarkable reduction of left ventricular dp/dtmax or mean aortic pressure in anesthetized dogs.

A series of 1,2-dihydro-5-imidazo[1,2-a]pyridinyl-2(1H)-pyridonones was synthesized and evaluated for positive inotropic activity, 1,2-Dihydro-5-imidazo[1,2-a]pyridin-6-yl-6-methyl-2- oxo-3-pyridinecarbonitrile (11a) hydrochloride monohydrate (E-1020) was found to be a potent and selective inhibitor of phosphodiesterase III and a long-acting, potent, orally active positive inotropic agent. Additional imidazo[1,2-a]pyridin-2-yl (3a), -3-yl (16), -7-yl (20) and -8-yl (24a) compounds were also prepared. Altering the pyridine substitution from the 2-position to the 6-position produced a 2-fold increase in the i.v. cardiotonic potency (ED50) from 52 to 23 micrograms/kg, while substitution at the 3-, 7- or 8-position reduced potency. In the 2-positional isomers, introduction of halogen groups enhanced the activity and 3-chloro-1,2-dihydro-5-(6-fluoroimidazo[1,2-a] pyridin-2-yl)-6-methyl-2(1H)-pyridinone (3u) was the most potent (i.v. ED50 11 micrograms/kg) in this series. E-1020 is presently under development for the treatment of congestive heart failure.

A series of novel 4,5-dihydro-5-methyl-6-(2 or 4-substituted 7-quinazolinyl)-3(2H)-pyridazinones was synthesized and examined for cardiotonic activity in anesthetized dogs. The 4-substituted aminoquinazolines generally showed potent and long-lasting inotropic activity. Fall in the activity was observed on the introduction of substituent at the 2-position of the quinazoline ring. The 3-substituted 4 (3H)-quinazolinimines generally exhibited weak activity. Ca2+ sensitizing effect of the 4-substituted amino derivatives was also examined in chemically skinned fiber from papillary muscle of guinea pig. The alkylamino derivatives exhibited small sensitizing effect, while the benzylamino derivatives exhibited large effect. Among them, KF15232 (Ix) was found to have the most potent cardiotonic and Ca2+ sensitizing activities.

Several benzothiazolyl, imidazobenzothiazolyl, benzothienyl, benzothienopyrimidinyl and quinazolinyl 4,5-dihydro-3(2H)-pyridazinones were synthesized and examined for cardiotonic activity in anesthetized dogs after i.v. administration. Among them, 4-methylamino-7-(2,3,4,5-tetrahydro-5-methyl-3-oxo-6- pyridazinyl)quinazoline (36) showed potent and long-lasting inotropic activity (relative potency = 2.11, milrinone = 1). The activity of 36 was more potent than indolidan (2) (relative potency = 1.53) which is one of the most potent inotropic agents to date.

A series of 1-(6,7-dimethoxy-4-quinazolinyl)piperidines carrying various 5-membered heterocycles at the 4-position was synthesized and examined for cardiotonic activity in anesthesized dogs. The (4-oxo-2-thioxo-3-imidazolindinyl)amino derivatives showed the most potent inotropic activity. Marked loss of activity was observed in the 2,4-dihydro-3-thioxo-3H-1,2,4-triazolyl, the 2,4-dihydro-3-oxo-3H-pyrazolyl and the (2,3-dihydro-2-thioxo-3H-1,3,4-thiadiazol-5-yl)amino derivatives. The synthesis and structure-activity relationships are discussed.

A series of novel N6,N6-dialkyl adenosine 3',5'-cyclic phosphates N6,N6-dialkyl cAMPs) was synthesized from 2'-O-p-toluenesulfonyl cAMP (2'-O-tosyl cAMP, 2) and tested for inotropic and chronotropic activities in vitro. Treatment of 2 with excess alkyl halides and sodium hydride followed by detosylation with aqueous NaOH readily gave N6,N6-dialkyl cAMPs (3) in good yields. Various N6,N6-dialkyl cAMPs having different alkyl groups at the N6-position (9-12) were prepared by alkylation followed by detosylation of N6-alkyl-2'-O-tosyl cAMPs (4) which were obtained by the reductive alkylation of 2 with aldehydes in the presence of sodium cyanoborohydride in acetic acid or tosylation of N6-methyl cAMP. The mechanism of the detosylation is briefly discussed. Among the N6,N6-dialkylated derivatives, N6,N6-dipentyl (3f) and N6-ethyl-N6-heptyl (10e) derivatives were found to exhibit a potent positive inotropic effect and a weak positive chronotropic effect. The structure-activity relationships for the position and the length of alkyl residue are discussed.

A series of novel 1-(6,7-dimethoxy-4-quinazolinyl)piperidines carrying substituted hydantoin and 2-thiohydantoin rings was synthesized and examined for cardiotonic activity in anesthetized dogs. Introduction of isopropyl and sec-butyl group at the 5-position of the hydantoin and thiohydantoin rings led to potent inotropic activity. Effects of insertion of an alkyl chain between the piperidine and the hydantoin rings were also examined. The structural requirements necessary for optimal cardiotonic activity within the series were investigated.

A series of 1-[1-(6,7-dimethoxy-4-quinazolinyl)-4-piperidinyl]-3-substituted 2-imidazolidinone and 2-imidazolidinethione derivatives was synthesized and examined for cardiotonic activity in anesthetized dogs. Alkylation of the 2-imidazolidinone (1) afforded the N-alkylated products, while alkylation of the 2-imidazolidinethione (12) afforded the S-alkylated derivatives accompanied with a small quantity of the N-alkylated products. The N-alkylated derivatives showed generally potent activity, and the S-alkylated ones exhibited weak activity. Insertion of an alkyl group between the piperidine and the imidazolidinone moiety generally resulted in a fall in activity.

A series of phthalazine and 1,2,3-benzotriazine derivatives which have heterocyclylpiperidino groups was synthesized and tested for cardiotonic activity in anesthetized dogs. Several 6,7-dimethoxyphthalazine derivatives showed relatively potent cardiotonic activity comparable to that of amrinone.

A series of quinazoline derivatives with various 4-heterocyclylpiperidino groups at the 4-position was synthesized and tested for cardiotonic activity in anesthetized dogs. Among them, several 6,7-dimethoxyquinazoline derivatives showed potent cardiotonic activity.

Reactions of 4-methyl-2(3H)-thiazolones (5) with various N-alkoxycarbonyl pyridinium salts (6a--f) led to (N-alkoxycarbonyl dihydropyridyl)thiazolones (7a--f), oxidation of which yielded a new class of 5-pyridylthiazolones (8a--f). These reactions were applied to the synthesis of other azaarylthiazolones. Some of these azaarylthiazolones, particularly 5-(4-pyridyl)thiazolones (8b, c) and 5-(4-quinolyl)thiazolones (14a,b), showed positive inotropic activity with little chronotropic effect on guinea pig left atria.