Dihydropyridazinone cardiotonics: synthesis and inotropic activity of 5'-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)spiro[cycloalkane- 1,3'-[3H]indol]-2'(1'H)-ones

In the 1,3-dihydro-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)-2H-indol-2-one series of cardiotonics, we found that a spirocycloalkyl ring may be annealed to the 3-position of the indolone moiety while retaining inotropic activity. An inverse relationship was found between spirocyloalkyl ring size and inotropic potency. ED50 values of the spirocyclopropane 10, spirocyclobutane 12, and spirocyclopentane 13 were 2.7, 35, and 133 micrograms/kg, respectively, following iv administration to pentobarbital-anesthetized dogs. The most potent compound prepared was 11 (5'-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)spiro[cyclopropane- 1,3'-[3H]indol]-2'(1'H)-one), the 4-methyl analogue of 10. This compound had an iv ED50 of 1.5 microgram/kg. Oral activity was evaluated by administering 50 micrograms/kg of 10 to conscious, chronically instrumented dogs. A 39% increase in LV dP/dt60 was observed, and an inotropic effect was demonstrable in excess of 7 h. Thus, the spirocyclic dihydropyridazinone inotropes are potent, long-acting, orally effective cardiotonics. Compound 11 was a potent inhibitor (IC50 = 13 nM) of cAMP phosphodiesterase derived from canine cardiac sarcoplasmic reticulum (SR-PDE). Importantly, -log IC50 values for inhibition of SR-PDE for this entire series of compounds were highly correlated (r = 0.949, p less than 0.02) with their inotropic -log ED50 values, supporting the hypothesis that inhibition of this enzyme contributes to the mechanism of action of the spirocyclic dihydropyridazinones.     

Molecular structure of the dihydropyridazinone cardiotonic 1,3-dihydro-3,3-dimethyl-5-(1,4,5,6-tetrahydro-6-oxo-pyridazinyl)- 2H-indol-2-one, a potent inhibitor of cyclic AMP phosphodiesterase

The cardiotonic 1,3-dihydro-3,3-dimethyl-5-(1,4,5,6-tetrahydro-6-oxo-3- pyridazinyl)-2H-indol-2-one (1, LY195115) is a potent, competitive inhibitor (Ki = 80 nM) of sarcoplasmic reticulum derived phosphodiesterase (SR-PDE). Moreover, the compound is a potent positive inotrope both in vitro and in vivo. To assist further cardiotonic drug-design studies, we have mapped the three-dimensional structure of 1 using X-ray crystallography. From a global viewpoint, this drug was essentially planar, but two small regions of nonplanarity were apparent. These involved the geminal methyl substituents in the indol-2-one moiety and the C5' methylene unit of the dihydropyridazinone ring. Because of our previous studies involving the bipyridine cardiotonics amrinone and milrinone, the conformational relationship between the plane of the phenyl ring and the horizontal symmetry plane defined by N2', C3', and C4' of 1 was of particular interest. The C6-C5-C3'-C4' dihedral angle was -2.7 degrees, whereas the C6-C5-C3'-N2' dihedral angle was 174.6 degrees. Therefore the two rings maintain a high degree of coplanarity. Compound 4, the congener of 1 possessing a completely unsaturated pyridazinone ring was also studied. In terms of inotropic activity, this compound, devoid of any puckering in the pyridazinone moiety, was equipotent with 1. Methyl substitution at the 4-position of the dihydropyridazinone and pyridazinone rings provided disparate results. Compound 2, the 4-methyl analogue of 1, was 2-fold more potent than 1, and the methyl substituent probably caused only minor perturbations in overall molecular topology. However 5, the 4-methyl analogue of the pyridazinone 4, was 4.4-fold less active than 4, perhaps as a result of methyl-induced molecular nonplanarity.     

Nonsteroidal cardiotonics. 3. New 4,5-dihydro-6-(1H-indol-5-yl)pyridazin-3(2H)-ones and related compounds with positive inotropic activities

A series of substituted indolyldihydropyridazinones and related compounds 1-18 were synthesized and evaluated for positive inotropic activity. In rats, most of these indole derivatives produced a dose-related increase in myocardial contractility with little effect on heart rate and blood pressure. Compound 13, 4,5-dihydro-5-methyl-6-(2-pyridin-4-yl-1H-indol-5-yl)pyrazin-3(2H) -one (BM 50.0430), was further investigated in cats. The increase in contractility in this animal model was not mediated via stimulation of beta-adrenergic receptors. After oral administration of 1 mg/kg to conscious dogs, compound 13 and pimobendan were still active after 6.5 h. However, the cardiotonic effect of 13 was at least 2-fold that of pimobendan after this period of time. The structural requirements necessary for optimal cardiotonic activity within this novel class of indole derivatives are a heterocyclic aromatic ring in position 2, a hydrogen or a methyl group in position 3, and a dihydropyridazinone ring system in position 5 of the indole.     

Nonsteroidal cardiotonics. 2. The inotropic activity of linear, tricyclic 5-6-5 fused heterocycles

We previously reported the structure-activity relationships (SAR) of adibendan (1), a potent and long-acting cardiotonic. This paper describes the synthesis of a novel series of linear, tricyclic fused heterocycles of the 5-6-5 type. The compounds were evaluated for positive inotropic activity in anesthetized rats, cats, and dogs. Changes in left ventricular dP/dt were measured as an index of cardiac contractility. The increase in contractility was not mediated via stimulation of beta-adrenergic receptors. The data revealed the intrinsic positive inotropic activity of the parent compound of this series, 5,7-dihydro-7,7-dimethylpyrrolo[2,3-f]benzimidazol-6(1H)-one (2). The structural features that impart optimal inotropic activity are presented and compared with those of the 4,5-dihydro-3(2H)-pyridazinone series. The most potent compounds were evaluated orally in conscious dogs with implanted Konigsberg pressure transducers to measure ventricular pressures, and their effect on left ventricular dP/dt was compared with that of 1, pimobendan, and indolidan. After administration of 1 mg/kg, 1, 3, 7, 19, 22, 24, 31, 54, pimobendan, and indolidan were equipotent, but only with 1, 31, pimobendan, and indolidan, durations of action exceeded 6 h.     

(9S)-9-(2-hydroxy-4,4-dimethyl-6-oxo-1-cyclohexen-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one, a selective and orally active neuropeptide Y Y5 receptor antagonist

(9S)-9-(2-Hydroxy-4,4-dimethyl-6-oxo-1-cyclohexen-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one ((S)-1) was identified as a selective and orally active neuropeptide Y Y5 receptor antagonist. The structure-activity relationship for this structural class was investigated and showed that limited substitution on the phenyl ring was tolerated and that modification of the 4,4-dimethyl group of the cyclohexenone and the 3,3-dimethyl group of the xanthenone parts slightly improved potency. The plasma concentration-time profile after oral administration of (S)-1 in Sprague-Dawley (SD) rats showed significant in vivo racemization of (S)-1 and that (S)-1 is cleared much more quickly than (R)-1. The duration of (S)-1 in SD rats after oral administration of (RS)-1 racemate was twice as long as that following oral administration of (S)-1. The C max values of (S)-1 after administration of (S)-1 and (RS)-1 were comparable, and the brain to plasma ratio for (S)-1 was 0.34 in SD rats. In our acute D-Trp (34)NPY-induced food intake model, both (S)-1 and (RS)-1 showed potent and dose-dependent efficacy. Therefore, the use of (RS)-1 is suitable for studies that require sustained plasma exposure of (S)-1.     

1,3-二甲基-6-[2-(对甲苯磺酰氧基)乙基氨基]尿嘧啶的合成

目的:合成盐酸尼非卡兰中间体1,3-二甲基-6-[2-(对甲苯磺酰氧基)乙基氨基]尿嘧啶.方法:以二甲基脲和氰乙酸为原料经3步反应合成目标产物.结果:以氰乙酸计,总收率44.4%.目标产物的光谱数据与文献报道一致.结论:新的合成方法所用原料价廉易得,适合生产.     

6-(4-取代乙酰氨基苯基)-4,5-二氢-3(2H)-哒嗪酮衍生物的合成及其抗血小板凝集活性

目的研究引入仲胺类基团对6-（4-取代乙酰氨基苯基）-4，5-二氢-3（2H）-哒嗪酮类化合物抗血小板凝集活性的影响。方法设计合成未见报道的目标化合物13个，用。H—NMR、IR、MS确证结构，参考Bom方法进行体外药理实验。结果与结论所有化合物都具有抗血小板凝集的活性，其中化合物6b、6g的抗血小板凝集活性明显优于MCI-154。仲胺类基团的空间位阻和亲水性对化合物抗血小板凝集的活性有影响。     

Antihypertensive and antithrombotic activities of 6-(substituted phenyl)-5-hydroxymethyl-4,5-dihydro-3(2H)pyridazinones

The synthesis of a series of 6-(4R-phenyl)-5-hydroxymethyl-4,5-dihydro-3(2H)pyridazinones is reported. The compounds were evaluated for their oral antihypertensive activity in rats and some of them [(V b), R = NH2] and [(V c), R = NHCOCH3] were found to induce a high decrease in systolic blood pressure. Moreover all the compounds displayed an antithrombotic activity comparable to, or greater than, that of ASA.     

Synthesis and cardiovascular activity of new 8-alkylamino-1,3-dimethyl-7-(2-hydroxy-3- piperazinopropyl)-3,7-dihydro-1H-purine-2,6-diones

7-{2-Hydroxy-3-[4-(2-phenoxyethyl)-piperazinyl-1-yl]-propyl}-1,3-di-methyl-3,7-dihydro-1H-purine-2,6-dione dihydrochloride (2), and several of its 8-alkylamino substituted derivatives (11-17) were synthesized and tested for electrocardiographic, antiarrhythmic and hypotensive activity. Also their alpha(1)- and alpha(2)-adrenoreceptor affinities were determined. It was found that compound 2, and its analogue 15 with 8-(2-morpholin-4-yl-ethylamino) substituent displayed a strong prophylactic antiarrhythmic activity in experimentally induced arrhythmia (LD50/ED50 = 54.9 and 55.0, respectively). The hypotensive activity was observed for 8-benzylamino (11) or 8-(pyridin-2-yl-methylamino) (12) analogues. All the new derivatives (11-17) and 2 showed a weak affinity for alpha1-(Ki = 0.225-1.400 microM) and alpha2-(Ki = 0.152-4.299 microM) receptors.     

Structure-activity relationships of arylimidazopyridine cardiotonics: discovery and inotropic activity of 2-[2-methoxy-4-(methylsulfinyl)phenyl]-1H-imidazo[4,5-c]pyridine

Recently several noncatecholamine, nonglycoside cardiotonic drugs have been discovered that possess both inotropic and vasodilator activities in experimental animals and man. Prototypical compounds include amrinone, sulmazole, and fenoximone. We investigated the structural requirements necessary for optimal inotropic activity in a series of molecules containing a heterocyclic ring fused to 2-phenylimidazole and discovered that 2-phenylimidazo[4,5-c]pyridines were generally 5-10-fold more potent than analogous 2-phenylimidazo[4,5-b]pyridines (e.g., sulmazole) or 8-phenylpurines. Furthermore, all imidazo[4,5-c]pyridine analogues we tested were orally active; in contrast, only one of the imidazo[4,5-b]pyridine derivatives, sulmazole, was significantly active. One of several highly active compounds in the [4,5-c] series was 50 (LY175326, 2-[2-methoxy-4-(methylsulfinyl)phenyl]-1H-imidazo[4,5-c]pyridine hydrochloride). The structure-activity relationship of this series is presented and compared to that of the imidazo[4,5-b]pyridine and purine series.     

6-(4-取代乙酰氨基苯基)-4，5-二氢-3(2H)哒嗪酮衍生物的合成及其抑制血小板聚集活性

目的:研究引入杂环类基团对6-(4-取代乙酰氨基苯基)-4,5-二氢-3(2H)哒嗪酮类化合物抗血小板凝集活性的影响.方法:设计合成未见报道的目标化合物10个,所有化合物均经过1H-NMR谱等确证;参考Born方法进行体外药理实验.结果:所有化合物都具有抗血小板凝集的活性,其中化合物(5),(9)和(10)的抗血小板凝集活性明显优于MCI-154.结论:杂环基团的空问位阻和亲水性对化合物抗血小板凝集的活性有影响.     

Design, synthesis, and SAR of new pyrrole-oxindole progesterone receptor modulators leading to 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-1-methyl-1H-pyrrole-2-carbonitrile (WAY-255348)

We have continued to explore the 3,3-dialkyl-5-aryloxindole series of progesterone receptor (PR) modulators looking for new agents to be used in female healthcare: contraception, fibroids, endometriosis, and certain breast cancers. Previously we reported that subtle structural changes with this and related templates produced functional switches between agonist and antagonist properties ( Fensome et al. Biorg. Med. Chem. Lett. 2002, 12, 3487; 2003, 13, 1317 ). We herein report a new functional switch within the 5-(2-oxoindolin-5-yl)-1 H-pyrrole-2-carbonitrile class of compounds. We found that the size of the 3,3-dialkyl substituent is important for controlling the functional response; thus small groups (dimethyl) afford potent PR antagonists, whereas larger groups (spirocyclohexyl) are PR agonists. The product from our optimization activities in cell-based systems and also for kinetic properties in rodents and nonhuman primates was 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1 H-indol-5-yl)-1-methyl-1 H-pyrrole-2-carbonitrile 27 (WAY-255348), which demonstrated potent and robust activity on PR antagonist and contraceptive end points in the rat and also in cynomolgus and rhesus monkeys including ovulation inhibition, menses induction, and reproductive tract morphology.     

Synthesis and beta-adrenergic blocking activity of oxipropanolamines of 3,4-dihydro-3-oxo-2H(1,4)benzothiazine

The synthesis of a series of oxypropanolamines of 3,4-dihydro-3-oxo-2H(1,4)benzothiazine is reported. Some of these compounds proved more potent than propranolol and carteolol as beta-adrenergic blocking agents in in vitro tests. The 8-(3-tert-butylamino-2-hydroxy)propoxy-3,4-dihydro-3-oxo-2H(1,4) benzothiazine fumarate (XVI a), which gave better results, confirmed its remarkable activity in in vivo tests.     

The disposition of 2-cyano-1-methyl 3-(4-(4-methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)phenyl)guanidine in animals

2-Cyano-1-methyl 3-(4-(4-methyl-6-oxo-1,4,5,6-tetrahydro-pyridazin-3-yl)phenyl)guan idine (SK&F 94836), a new positive inotrope/vasodilator, is being evaluated for the treatment of congestive heart failure. The absorption, metabolism, and disposition of the compound have been investigated in the rat, mouse, and dog. SK&F 94836 was rapidly absorbed, widely distributed, and rapidly and completely excreted primarily via the urine. There was no evidence of metabolism of the compound in any of the species studied. The compound showed minimal interaction with cytochrome P-450. The compound contains a chiral center. The enantiomers have been shown not to interconvert in either rat or dog. The serum protein binding was low in all species, including humans, and exhibited no stereoselectivity. Studies conducted in rat and dog using constant rate co-infusion of racemic SK&F 94836 and radiolabeled inulin have demonstrated that SK&F 94836 is eliminated by active tubular secretion.