Access to Multifunctionalized Benzofurans by Aryl Nickelation of Alkynes: Efficient Synthesis of the Anti-Arrhythmic Drug Amiodarone.

An unconventional nickel-catalyzed reaction was developed for the synthesis of multifunctionalized benzofurans from alkyne-tethered phenolic esters. The transformation involves the generation of a nucleophilic vinyl NiII species by the regioselective syn-aryl nickelation of an alkyne, which then undergoes an intramolecular cyclization with phenol ester to yield highly functionalized 1,1-disubstituted alkenes with 3-benzofuranyl and (hetero)aryl substituents. The methodology can be used for the late-stage benzofuran incorporation of various drug molecules and natural products, such as 2-propylvaleric acid, gemfibrozil, biotin, and lithocholic acid. Furthermore, this arylative cyclization method was successfully applied for the efficient synthesis of the anti-arrhythmic drug amiodarone.

Synthesis and Structure-Activity Relationships of a Series of Aporphine Derivatives with Antiarrhythmic Activities and Acute Toxicity.

Some aporphine alkaloids, such as crebanine, were found to present arrhythmic activity and also higher toxicity. A series of derivatives were synthesized by using three kinds of aporphine alkaloids (crebanine, isocorydine, and stephanine) as lead compounds. Chemical methods, including ring-opening reaction, bromination, methylation, acetylation, quaternization, and dehydrogenation, were adopted. Nineteen target derivatives were evaluated for their antiarrhythmic potential in the mouse model of ventricular fibrillation (VF), induced by CHCl3, and five of the derivatives were investigated further in the rat model of arrhythmia, induced by BaCl2. Meanwhile, preliminary structure-activity/toxicity relationship analyses were carried out. Significantly, N-acetamidesecocrebanine (1d), three bromo-substituted products of crebanine (2a, 2b, 2c), N-methylcrebanine (2d), and dehydrostephanine (4a) displayed antiarrhythmic effects in the CHCl3-induced model. Among them, 7.5 mg/kg of 2b was able to significantly reduce the incidence of VF induced by CHCl3 (p < 0.05), increase the number of rats that resumed sinus rhythm from arrhythmia, induced by BaCl2 (p < 0.01), and the number of rats that maintained sinus rhythm for more than 20 min (p < 0.01). Therefore, 2b showed remarkably higher antiarrhythmic activity and a lower toxicity (LD50 = 59.62 mg/kg, mice), simultaneously, indicating that 2b could be considered as a promising candidate in the treatment of arrhythmia. Structural-activity analysis suggested that variationsin antiarrhythmic efficacy and toxicity of aporphines were related to the C-1,C-2-methylenedioxy group on ring A, restricted ring B structural conformation, N-quaternization of ring B, levoduction of 6a in ring C, and the 8-, 9-, 10-methoxy groups on ring D on the skeleton.

Molecular hybridization, synthesis, and biological evaluation of novel chroman I(Kr) and I(Ks) dual blockers.

The combination of I(Kr) and I(Ks) blockade could lead to synergistic and safe class III anti-arrhythmic effect with the enhanced efficacy and reduced risk. On the rationale of structural hybridization of azimilide and HMR-1556, a novel series of I(Kr) and I(Ks) dual blockers were designed, synthesized and evaluated in vitro. One compound, 3r (CPUY11018), deserves further evaluation for its potent anti-arrhythmic activity and favorable cardiovascular profile.

Design, synthesis and pharmacological screening of novel antihypertensive agents using hybrid approach.

Eight derivatives of general formula 2-(2-(4-(3-((5-substituted methylene)-4-oxo-2-(phenylimino)thiazolidin-3-yl)-2-hydroxypropylamino)benzoyl)hydrazinyl)-2-oxoethyl nitrate were synthesized and tested for electrocardiographic, antiarrhythmic, vasorelaxing and antihypertensive activity as well as for in-vitro nitric oxide (NO) releasing ability. Compound 8b 2-(2-(4-(3-(5-benzyliden-4-oxo-2-(phenylimino)thiazolidin-3-yl)-2-hydroxypropylamino)benzoyl)hydrazinyl)-2-oxoethyl nitrate, was the most potent in this series. The pharmacological results suggested that the antiarrhythmic effects of these compounds were related to their adrenolytic properties which are believed to be due to the presence of the 5-(substituted)methylen-2-(phenylimino)thiazolidin-4-one moiety with less bulky, electron donating substituent on the phenyl ring at 5th position of the thiazolidin-4-one. In conclusion, most of the synthesized compounds were significantly potent as antiarrhythmic and antihypertensive; this might be due to the presence of different pharmacopores which might act at different locations with different mode of action. Further insights of the same can be obtained by doing investigation at receptor level. The potency of compounds 8a-8h were promising enough to continue further experiments.

[Prodrug structural modifications of cyclovirobuxine D and their biological activity].

AIM: To search for compounds for the treatment of cardiovascular diseases through prodrug structural modifications of cyclovirobuxine D, a single efficient composition distilled from Box plant in China, which was used to treat angina and myocardial infarction. METHODS: According to prodrug design principle, a series of cyclovirobuxine D analogues were prepared, suc as succinate, phosphate and amino acid ester, and their biological activities were tested. RESULTS: Seven new compounds were obtained and confirmed with 1H NMR, MS, and element analysis. CONCLUSION: In pharmacology experiment, for treating arrhythmia induced by aconitine, succinate and amino acid ester of cyclovirobuxine D (I and VII) showed better activities than that of cyclovirobuxine D. The normal rhythm of the heart duration of I and VII were ( 11.53 +/- 7.62) min and (12.68 +/- 9.25) min, compared with 0.9% NaCl solution and cyclovirobuxine D, (2.36 +/- 1.68) min and (10.25 +/- 6.59) min (P < 0.01), respectively. Another pharmacology experiment, for treating arrhythmia induced by chloroform, the negative ratio of I and VII were 80% and 82%, compared with 0.9% NaCl solution and cyclovirobuxine D, 43% and 52% (P < 0.05), respectively. The difference between new compounds and cyclovirobuxine D was distinct.

Synthesis and biological evaluation of novel 6-nitro-5-substituted aminoquinolines as local anesthetic and anti-arrhythmic agents: molecular modeling study.

A series of 6-nitro-5-[1-oxo-2-(substituted amino)ethylamino and 2-(substituted amino)propylamino] quinoline was synthesized and evaluated for their local anesthetic and anti-arrhythmic activity. The detailed synthesis, spectroscopic, and biological data are reported. Molecular modeling methods are used to study the local anesthetic activity of lidocaine and the active compounds by means of the AM1 method. The superposition of the stable conformations of these compounds was studied using the HyperChem 5.11 program.

[Structural modification and bioactivity of cyclovirobuxine D].

AIM: To search for new compounds for the treatment of cardiovascular diseases by structural modification of cyclovirobuxine D. METHODS: According to rational drug design principle, a series of cyclovirobuxine D analogues were prepared, and their bioactivities were tested. RESULTS: Ten new compounds were syntheized and confirmed by spectra. CONCLUSION: Endurance lacking oxygen activity and antiarrhythmia effects of some analogues of cyclovirobuxine D were tested. Some compounds showed better activity than cyclovirobuxine D.

Tedisamil: a new novel antiarrhythmic.

Solvay Pharmaceuticals is currently developing tedisamil (KC-8857), a novel antiarrhythmic with additional anti-ischaemic properties, which acts via potassium channel blockade. This drug can be categorised as a class III antiarrhythmic agent due to its effects of action potential and QT interval prolongation in these patients. This agent was initially developed for its anti-ischaemic properties and Phase I trials have shown tedisamil to be an effective bradycardic agent, as well as causing a reverse rate-dependent QT interval prolongation. Subsequent Phase II results have confirmed that in patients with ischaemic heart disease, tedisamil had beneficial haemodynamic and anti-ischaemic effects. Phase III studies in patients with ischaemic heart disease indicated that tedisamil is an effective agent for the treatment of angina, resulting in a dose-dependent increase in anginal threshold (with a decrease in anginal attacks, increased exercise capacity during treadmill exercise and decreased electrocardiographic signs of exercise induced ischaemia) in comparison to placebo. Although tedisamil has been shown to be an effective anti-ischaemic agent, with Phase III trials for angina pectoris now completed, the company are now pursuing the use of tedisamil for the treatment of atrial fibrillation, for which tedisamil is still in Phase II/III clinical trials. Launch data are not yet known.

[Anti-arrhythmic action of N-(aminoalkylene) derivatives of indoline-2,3-diones and 1,2-benzene-dicarboxiamides]. / Indolin-2,3-dionu ir 1,2-benzendikarboksimidu N-aminoalkilintu dariniu sinteze ir antiaritminis poveikis.

The aim of study was to modify the structure of indoline-2,3-diones and 1,2-benzenedicarboximides using the pharmacophores of new generation antiarrhythmics and to assess the impact of their structure upon the acute toxicity and antiarrhythmic action. The quaternary derivatives of N-aminoalkylindoline-2,3-diones and N-aminoalkyl-1,2-benzenedicarboximides were synthesized. The acute toxicity of compounds for white mice was tested. Using the calcium chloride- and aconitine-induced arrhythmia models in rats the antiarrhythmic action of derivatives was assessed. It was shown, that the antiarrhythmic action of N-aminoalkyl-1,2-benzenedicarboximides increases by lengthening of alkylene chain from one methylene group to two or by the presence of methanesulfonamide group in benzene ring. These structural changes, especially the presence of methanesulfonamido group, cause the decrease of acute toxicity. Among the N-aminoalkylindoline-2,3-diones the most antiarrhythmic action and minimal toxicity demonstrates the compound containing the bromo-substituted benzene ring.

3,8-diazabicyclo--[3.2.1]-octane derivatives as analogues of ambasilide, a Class III antiarrhythmic agent.

Ambasilide, a representative of Class III antiarrhythmics, was reported to prolong the cardiac action potential duration in the dog, with little or no effect on Ca and Na currents. We synthesised a series of ambasilide analogues, having the 3,8-diazabicyclo-[3.2.1]-octane moiety instead of the 3,7-diazabicyclo-[3.3.1]-nonane present in ambasilide. The compounds were tested both in vitro extracellular electrophysiological assays and by the conventional microelectrode technique. Most of them lengthened the effective refractory period (ERP) with no change or slight increase on the impulse conduction time (ICT). Similarly some of the tested compounds lengthened the action potential duration (APD), a typical Class III feature, without exerting any significant effect on the maximal rate of depolarization, therefore apparently lacking Class I antiarrhythmic activity.

Synthesis and biological activity of KCB-328 and its analogues: novel class III antiarrhythmic agents with little reverse frequency dependence.

A series of 3,4-dimethoxyphenethylamine derivatives was prepared, and their prolongation effects on effective refractory period of contractile response (ERPc) and action potential duration (APD) in isolated guinea-pig papillary muscles at 1 Hz and 3 Hz were examined. SAR studies led to the identification of KCB-328 (51) which is a novel class III antiarrhythmic agent with little reverse frequency dependence.

Syntheses and cardiovascular effects of some S-substituted 4-chloro-2-mercapto-5-methyl-N-(4-alkyl-4H-1,2,4-triazol-3-yl) benzenesulfonamides.

Syntheses of N-(2-dialkylaminoethyl)-(5-chloro-4-methyl-2-[(4-butyl or isobutyl -4H-1,2,4-triazol-3-yl)aminosulfonyl]phenylthio) alkanecarboxyamides [VII-X] and hydrochlorides [VIIa-Xa, XI-XIII] are described. Results of preliminary pharmacological examination such as acute toxicity and influence on the circulatory system of compounds [VIIa, IXa, Xa, XIII, XIV] are presented. The antiarrhythmic effect of the most active [IXa] was comparable to the reference procainamide.

Certain norditerpenoid alkaloids and their cardiovascular action.

Thirteen new derivatives of norditerpenoid alkaloids, namely, 8-deacetyl-8-p-aminobenzoyldelphinine (1), 8-deacetyl-8-anthranoyldelphinine (2), 8-deacetyl-8-(4-hydroxy-3-methoxycinnamoyl)delphinine (3), 16-demethoxy-15,16-didehydro-8-p-anisoyl-14-benzoyldelpho nine (4), 6-acetylheteratisine N-oxide (6), 3,8-diacetylfalconerine (7), 8-stearoylfalconerine (8), 8-linolenylfalconerine (9), 13-acetylpyrodelphinine (11), 13-acetyldelphinine N-oxide (13), N-deacetyl-8,9-diacetyllappaconitine (14), 8, 9-(methylenedioxy)lappaconine (15), and 16-epipyroaconitine N-oxide (17), were prepared, and their structures were established by analysis of spectroscopic data (1D and 2D NMR, HRFABMS). The preliminary in vivo cardiovascular action (hypotensive, bradycardic, and ventricular arrhythmias) of these new compounds was tested in male Sprague-Dawley rats. The results are reported herein.

Derivatives of 2-mercaptobenzenesulphonamide. XVII. Synthesis and some pharmacological properties of 1-[4-R-5-cyano-2-dialkylaminoalkylthio)benzenesulphonyl]-2-imidiazolidi none hydrochlorides.

Syntheses of 1-[4-R-5-cyano-2-(dialkylaminoalkylthio)-benzenesulphonyl]- 2-imidiazolidinones [IIIa-h,IVa-m] and their hydrochlorides [Va-h, VIa-m] are described herein. The results of preliminary pharmacological examinations, such as acute toxicity and influence on the circulatory system are presented. Some structure-activity relationship are also discussed.

[The anti-arrhythmic activity of the arylamides of alpha-hexamethyleneiminocarboxylic acids]. / Antiaritmicheskaia aktivnost' arilamidov al'fa-geksametileniminokarbonovykh kislot.

A high antiarrhythmic activity of arylamides of alpha-hexamethyleniminocarbonic acids was found on different experimental models of arrhythmias. It was shown that the lengthening of the carbonic chain in carbonic acids (R) as well as the change from ortho-toluidides to xylidides or mesidides in the aromatic fragment of the molecule increased the antiarrhythmic activity of the studied compounds, their toxicity also increased. The choice of compounds with optimal properties is determined by the combination of all investigated factors: intensity and duration and also the specific features of the spectrum of the antiarrhythmic effect, toxicity and therapeutic range.

[How to develop an anti-arrhythmia agent in 1990. The cardiologist's viewpoint]. / Comment développer un antiarythmique en 1990. Le point de vue du cardiologue.

The development of an antiarrhythmic drug in 1990 follows well established pathways. The first step is animal experimentation to establish the antiarrhythmic effect and to estimate the risk of toxicity, but clinical trial is the fundamental stage which confers on a product the title of antiarrhythmic. Several models may be used, one of which is ventricular extrasystoles. However, the data so obtained must not be extrapolated to a wider context. All methods for evaluating an antitachycardia effect have imperfections. Obviously, arrhythmias treated in hospital are privileged although they may only represent a special subgroup of more severe arrhythmias. Potential antiarrhythmics are more often assessed by their effects on tachycardias reproduced by programmed pacing, leaving other arrhythmias, including atrial fibrillation, to one side. In addition, long-term efficacy is more often suspected than demonstrated. The action on malignant ventricular tachyarrhythmias escapes all valid assessment mainly because of the difficulty of using a control group of patients with life-threatening arrhythmias. The use of automatic defibrillator devices could, in the near future, bring a more rigorous approach to this problem. One of the most important objectives of antiarrhythmic drugs is the prevention of sudden death. Results have been relatively disappointing until now. This may be due to deleterious, above all proarrhythmic, side-effects counterbalancing the benefits of the drug. The unwanted side-effects must be evaluated systematically in the future. The methodology needed is not yet established and requires further research.

Derivatives of (R,S)-1-N-(theophyllinyl-7'-ethyl)-amino-2-propanol with antiarrhythmic activity.

Three (R,S)-1-N-(theophyllinyl-7'-ethyl)-amino-2-propanol derivatives were obtained as soluble hydrochlorides and tested in four models of experimental arrhythmia. Two compounds 1a and 2 have shown antiarrhythmic properties and very low toxicity.

A search for new derivatives of chiral amino alcohols with an antiarrhythmic activity.

Twelve new (R) and (S) Schiff bases and twelve new (R) and (S) 2-benzylamino-1-butanols have been obtained. Pharmacological tests showed a weak antiarrhythmic and hypotensive activity of the screened chiral 2-benzylamino-1-butanols.

New antiarrhythmic agents. 2,2,5,5-Tetramethyl-3-pyrroline-3-carboxamides and 2,2,5,5-tetramethylpyrrolidine-3-carboxamindes.

N-(omega-Aminoalkyl)-2,2,5,5-tetramethyl-3-pyrroline- or -pyrrolidine-3-carboxamides were acylated on the primary amino group of the side chain by means of reactive acid derivatives (acid chlorides, activated esters, phthalic anhydrides, phthalimide, 2-alkyl-4H-3,1-benzoxazin-4-ones) or they were alkylated by forming the Schiff bases and subsequent sodium borohydride reduction. Other tetramethyl-3-pyrrolinecarboxamide compounds were synthesized by acylating the aminoalkyl compounds with 2,2,6,6-tetramethyl-3,5-dibromo-4-piperidinone in a reaction involving Favorskii rearrangement. Saturation of the double bond of some pyrroline derivatives furnished the pyrrolidinecarboxamides. The new compounds of each type were active against aconitine-induced arrhythmia and several of them had higher activity and better chemotherapeutic index than quinidine. A few selected examples from each type of the active new compounds showed strong activity against ouabain-induced arrhythmia; for comparison known drugs such as lidocaine, mexiletine, and tocainide were selected. The most potent compounds were oxidized to the paramagnetic nitroxides and the latter were reduced to the N-hydroxy derivatives; these products had no or only decreased antiarrhythmic effect.