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With the aim to discover a gastric antisecretory agent more potent than the existing proton pump inhibitors, novel 3,4-dihydro-1H-spiro(naphthalene-2,2'-piperidin)-1-one derivatives, which could occupy two important lipophilic pockets (described as LP-1 and LP-2) of H+,K+-ATPase and can strongly bind to the K+-binding site, were designed based on a docking model. Among the compounds synthesized, compound 4d showed a strong H+,K+-ATPase-inhibitory activity and a high stomach concentration in rats, resulting in potent inhibitory action on histamine-stimulated gastric acid secretion in rats. Furthermore, 4d exerted significant inhibitory action on histamine-stimulated gastric-acid secretion in rats with a rapid onset and moderate duration of action after the administration. These findings may lead to a new insight into the drug design of potassium-competitive acid blockers.

With the aim to find a novel long-lasting potassium-competitive acid blocker (P-CAB) that would perfectly overcome the limitations of proton pump inhibitors (PPIs), we tried various approaches based on pyrrole derivative 1b as a lead compound. As part of a comprehensive approach to identification of a new drug, we explored excellent compounds that have low lipophilicity by introducing a polar hetero-aromatic group at position 5 of the pyrrole ring. Among the compounds synthesized, fluoropyrrole derivative 37c, which has a 2-F-3-Py group at the fifth position, lower pKa, and much lower ClogP and logD values than 1b dose, showed potent gastric-acid suppressive action resulting from gastric H+,K+-ATPase inhibition in animal models. Its maximum intragastric pH elevation effect was strong in rats, and its duration of action was much longer than that of either lansoprazole or lead compound 1b in dogs. Therefore, compound 37c can be considered a promising new P-CAB with long duration of action.

A series of 1H-pyrrolo[2,3-c]pyridine-7-amine derivatives were designed and synthesized based on our docking model as potassium-competitive acid blockers (P-CABs). Molecular modeling of these derivatives led us to introduce a substituent at the 1-position to access two lipophilic sites and polar residues. We identified potent P-CABs that exhibit excellent inhibitory activity in vitro and in vivo. These results indicate that the 1H-pyrrolo[2,3-c]pyridine-7-amine derivatives are promising lead compounds as P-CABs.

To discover a gastric antisecretory agent more potent than existing proton pump inhibitors, novel pyrrole derivatives were synthesized, and their H(+),K(+)-ATPase inhibitory activities and inhibitory action on histamine-stimulated gastric acid secretion in rats were evaluated. Among the compounds synthesized, compound 17a exhibited selective and potent H(+),K(+)-ATPase inhibitory activity through reversible and K(+)-competitive ionic binding; furthermore, compound 17c exhibited potent inhibitory action on histamine-stimulated gastric acid secretion in rats and Heidenhain pouch dogs.

In our pursuit of developing a novel and potent potassium-competitive acid blocker (P-CAB), we synthesized pyrrole derivatives focusing on compounds with low log D and high ligand-lipophilicity efficiency (LLE) values. Among the compounds synthesized, the compound 13e exhibited potent H(+),K(+)-ATPase inhibitory activity and potent gastric acid secretion inhibitory action in vivo. Its maximum efficacy was more potent and its duration of action was much longer than those of proton pump inhibitors (PPIs). Therefore, compound 13e (1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methylmethanamine fumarate, TAK-438) was selected as a drug candidate for the treatment of gastroesophageal reflux disease (GERD), peptic ulcer, and other acid-related diseases.

3-Metoxycarbonyl isoquinolone derivative 1 has been identified as a potent JNK inhibitor and significantly inhibited cardiac hypertrophy in a rat pressure-overload model. Herein, a series of isoquinolones with an imidazolylmethyl or a pyrazolylmethyl group at the 2-position were designed based on X-ray crystallographic analysis of the complex between the isoquinolone compound and JNK3, as wells as the relationship between compound lipophilicity (log D) and activity in a cell-based assay. The compounds prepared showed potent JNK1 inhibitory activities in a cell-based assay. Among them the isoquinolone derivative possessing 5-[(cyclopropylamino)carbonyl]-1-methyl-1H-pyrazole (16e) exhibited significant anti-hypertrophic activity at doses of more than 1 mg/kg (po) in a pressure-overload model.

On the basis of a series of novel and potent potassium-competitive acid blockers represented by 1-sulfonylpyrrole derivative 7 , we prepared several five-membered heterocyclic analogues ( 8 ) and evaluated their H + ,K + -ATPase activities in vitro. We also assessed the role of the methylaminomethyl side chain by comparison with methylamino and ethylamino derivatives. We observed that the five-membered core ring and its orientation affect inhibitory activity and that the methylaminomethyl moiety is the best side chain. On the basis of potency and ligand-lipophilicity efficiency, compound 7 remains the most drug-like of the compounds studied to date. This study revealed the factors necessary for potent H + ,K + -ATPase inhibition, such as differences in electron density, the properties of the lone pair at each apical position of the heteroaromatic ring, and the geometry of the substituents.

A series of 1H-pyrrolo[2,3-c]pyridine-7-amine derivatives were designed and synthesized based on our docking model as potassium-competitive acid blockers (P-CABs). Molecular modeling of these derivatives led us to introduce a substituent at the 1-position to access two lipophilic sites and polar residues. We identified potent P-CABs that exhibit excellent inhibitory activity in vitro and in vivo. These results indicate that the 1H-pyrrolo[2,3-c]pyridine-7-amine derivatives are promising lead compounds as P-CABs.

A series of 3-quinolylurea derivatives (1) was synthesized and evaluated for acyl-CoA:cholesterol acyltransferase (ACAT) inhibitory activity. For in vitro studies, the most potent inhibitory activity was found in derivatives having substituents at the 6,7- or 6,8-positions and an ortho-substituted phenyl group at the 4-position of quinoline ring. The 2,4-difluorophenyl group appeared to be the optimum N'-substituent of the urea moiety. The IC 50 values of compounds 52-54 and 80 were in the nanomolar order. Plasma cholesterol-lowering activity of compounds 50, 52, and 54 was observed at less than 1 mg/kg/day in cholesterol-fed rats. Compound 52 was also hypocholesterolemic in hamsters fed a diet without loading cholesterol

H(+),K(+)-ATPase is a key enzyme in the process of gastric acid secretion, and proton pump inhibitors (PPIs) have been accepted as one of the most effective treatments for peptic ulcer and gastroesophageal reflux disease. To discover a novel class of PPIs, the authors screened a low-molecular-weight compound library and identified two prospective acid blockers that were pyrrole derivatives. Both compounds inhibited H(+),K(+)-ATPase in a reversible and potassium-competitive manner. These compounds led to the development of TAK-438 (1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methylmethanamine monofumarate), which is currently undergoing clinical trials as a novel potassium-competitive acid blocker for the treatment of acid-related diseases.

Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related diseases. However, several medical needs such as suppression of night-time acid secretion and rapid symptom relief remain unmet. In this study, we investigated the effects of 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methylmethanamine monofumarate (TAK-438), a novel potassium-competitive acid blocker, on acid secretion in rats and dogs under various conditions, in comparison with the PPI lansoprazole [2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl] methyl]sulfinyl]-1H-benzimidazole], to characterize the antisecretory action of TAK-438. TAK-438 showed a more potent and longer-lasting inhibitory effect than lansoprazole on the histamine-stimulated gastric acid secretion in rats and dogs. A pharmacokinetic study in rats showed that TAK-438 accumulated and was retained in the gastric tissue for more than 24 h, unlike that in the plasma. TAK-438 showed significant antisecretory activity with or without cimetidine pretreatment, in contrast to lansoprazole, which did not show antisecretory activity after cimetidine pretreatment in rats. TAK-438 increased the pH of the gastric perfusate to 5.7 in an unstimulated condition, and this effect was maintained in the presence of subsequent histamine stimulation. On the other hand, lansoprazole also increased the pH in an unstimulated condition, but this effect diminished after histamine stimulation. These results indicated that TAK-438 exerted a more potent and longer-lasting antisecretory effect than lansoprazole through high accumulation and slow clearance from the gastric tissue. In addition, TAK-438 was unaffected by the gastric secretory state, unlike PPIs. Therefore, TAK-438 can provide a novel mechanism of action to improve the present PPI-based treatment of acid-related diseases.

Inflammatory bowel disease (IBD) is a group of chronic inflammatory disorders that are primarily represented by ulcerative colitis and Crohn's disease. The etiology of IBD is not well understood; however, oxidative stress is considered a potential etiological and/or triggering factor for IBD. We have recently reported the identification of BTZO-1, an activator of antioxidant response element (ARE)-mediated gene expression, which protects cardiomyocytes from oxidative stress-induced insults. Here we describe the potential of BTZO-15, an active BTZO-1 derivative for ARE-activation with a favorable ADME-Tox profile, for the treatment of IBD. BTZO-15 induced expression of heme oxygenase-1 (HO-1), an ARE-regulated cytoprotective protein, and inhibited NO-induced cell death in IEC-18 cells. Large intestine shortening, rectum weight gain, diarrhea, intestinal bleeding, and an increase in rectal myeloperoxidase (MPO) activity were observed in a dextran sulfate sodium (DSS)-induced colitis rat model. Oral administration of BTZO-15 induced HO-1 expression in the rectum and attenuated DSS-induced changes. Furthermore BTZO-15 reduced the ulcerated area and rectal MPO activity in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rats without affecting rectal TNF-α levels. These results suggest that BTZO-15 is a promising compound for a novel IBD therapeutic drug with ARE activation properties.

TAK-438 is a novel potassium-competitive acid blocker (P-CAB) type antisecretory agent that reversibly inhibits gastric H + , K + -ATPase. Previously, we showed that TAK-438 has superior efficacy compared to lansoprazole, a proton pump inhibitor, in the inhibition of acid secretion in vivo . In this study, we investigated the differences in the mode of actions of the two drugs using primary cultured rabbit gastric glands. TAK-438 and lansoprazole inhibited gastric acid formation in acutely isolated gastric glands (IC 50 values, 0.30 and 0.76 μM, respectively). In cultured gastric glands that were preincubated with TAK-438, the inhibitory effect on forskolin-stimulated acid formation was augmented over the incubation period, whereas the inhibitory effect of lansoprazole was not affected by time of incubation. Next, we evaluated the durations of the actions of TAK-438 and lansoprazole after gastric glands were incubated with either drug for 2 h followed by washout. Even 8 h after the drug washout, TAK-438 at higher concentrations inhibited acid formation, but the inhibitory effect of lansoprazole disappeared immediately after washout. Additionally, only a small amount of [ 14 C] lansoprazole accumulated in resting glands, and this accumulation was enhanced by treatment with 1 μM of forskolin. In contrast, high levels of [ 14 C] TAK-438 accumulated in both resting and forskolin-treated glands. Furthermore, a 2-h preincubation followed by washout demonstrated a slow clearance of [ 14 C] TAK-438 from the glands. These findings suggest that TAK-438 exerts a longer and more potent antisecretory effect than lansoprazole as a result of its high accumulation and slow clearance from the gastric glands.

A series of new 1,4-benzoxazine derivatives (XI, XII) possessing (4-phenyl-1-piperazinyl)alkyl moieties at the 2-position and related compounds (XIII) were synthesized and tested for calcium antagonistic, calmodulin antagonistic and antihypertensive activities. Various compounds had in vitro calmodulin antagonistic activity superior or comparable to that of trifluoperazine. Among these compounds, tetrahydronaphtho[2,3-b] [1,4]oxazine derivatives such as 51, 53, 54, 58, 59, 60, 73 and 75 showed potent antihypertensive effects in spontaneously hypertensive rats. Optical isomers of 51 were also synthesized and evaluated biologically. No differences in biological activities were seen between the enantiomers.

A one-step synthesis of new pyrido [2,3-d] pyrimidine derivatives (III) was achieved through the Hantzsch synthesis using 6-aminouracils (I) as enamine nucleophiles

New 2H-1,4-benzothiazin-3(4H)-one derivatives possessing (4-phenyl-1-piperazinyl)alkyl moieties at the 2-position were synthesized and tested for calcium antagonistic and calmodulin antagonistic activities. Antihypertensive effects in spontaneously hypertensive rats were also evaluated. In general, these compounds were rather weak calcium channel blockers, although, in contrast, many of them had moderate to potent calmodulin antagonistic activity, and 2-[3-(4-(4-fluorophenyl)-1-piperazinyl]propyl]-2H-1,4-benzothiazin -3 (4H)-one derivatives 45, 74 and 75 showed potent antihypertensive effects.

Proton pump inhibitors (PPIs) are widely used in the treatment of acid-related diseases. However, several unmet medical needs, such as suppression of night-time acid secretion and rapid symptom relief, remain. In this study, we investigated the pharmacological effects of 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1 H -pyrrol-3-yl]- N -methylmethanamine monofumarate (TAK-438), a novel potassium-competitive acid blocker (P-CAB), on gastric acid secretion in comparison with lansoprazole, a typical PPI, and SCH28080 [3-(cyanomethyl)-2-methyl,8-(phenylmethoxy)imidazo(1,2- a )pyridine], a prototype of P-CAB. TAK-438, SCH28080, and lansoprazole inhibited H + ,K + -ATPase activity in porcine gastric microsomes with IC 50 values of 0.019, 0.14, and 7.6 μM, respectively, at pH 6.5. The inhibitory activity of TAK-438 was unaffected by ambient pH, whereas the inhibitory activities of SCH28080 and lansoprazole were weaker at pH 7.5. The inhibition by TAK-438 and SCH28080 was reversible and achieved in a K + -competitive manner, quite different from that by lansoprazole. TAK-438, at a dose of 4 mg/kg (as the free base) orally, completely inhibited basal and 2-deoxy-d-glucose-stimulated gastric acid secretion in rats, and its effect on both was stronger than that of lansoprazole. TAK-438 increased the pH of gastric perfusate to a higher value than did lansoprazole or SCH28080, and the effect of TAK-438 was sustained longer than that of lansoprazole or SCH28080. These results indicate that TAK-438 exerts a more potent and longer-lasting inhibitory action on gastric acid secretion than either lansoprazole or SCH28080. TAK-438 is a novel antisecretory drug that may provide a new option for the patients with acid-related disease that is refractory to, or inadequately controlled by, treatment with PPIs.

Summary In a screening program to discover therapeutic drugs for heart diseases, we identified BTZO-1, a 1,3-benzothiazin-4-one derivative, which activated antioxidant response element (ARE)-mediated gene expression and suppressed oxidative stress-induced cardiomyocyte apoptosis in vitro. An active BTZO-1 derivative for ARE-activation protected heart tissue during ischemia/reperfusion injury in rats. Macrophage migration inhibitory factor (MIF), which is known to protect cells from oxidative insult, was identified as a specific BTZO-1-binding protein. BTZO-1 binds to MIF with a K d of 68.6 nM, and its binding required the intact N-terminal Pro1. MIF, in the presence of BTZO-1, activated the glutathione S-transferase Ya subunit (GST Ya) gene ARE, whereas reduction of cellular MIF protein levels by siRNA suppressed BTZO-1-induced GST Ya expression. These results suggest that BTZO-1 activates the GST Ya gene ARE by interacting with MIF.

New 2H-1,4-benzothiazin-3(4H)-one derivatives possessing (4-phenyl-1-piperazinyl)alkyl moieties at the 2-position were synthesized and tested for calcium antagonistic and calmodulin antagonistic activities. Antihypertensive effects in spontaneously hypertensive rats were also evaluated. In general, these compounds were rather weak calcium channel blockers, although, in contrast, many of them had moderate to potent calmodulin antagonistic activity, and 2-[3-(4-(4-fluorophenyl)-1-piperazinyl]propyl]-2H-1,4-benzothiazin -3 (4H)-one derivatives 45, 74 and 75 showed potent antihypertensive effects.

A series of novel ([1,2,4]triazolo[1,5-b]pyridazin-6-yl) oxyalkylsulfonamides was synthesized and evaluated for the ability to inhibit platelet activating factor (PAF)-induced bronchoconstriction in guinea pigs. The compounds bearing a gem-dialkyl or a cycloalkylidene group at the 2 position of the sulfamoylpropyloxy group in the side chain and a methyl group at the 7 position were found to have potent activity. Among them, 2,2-diethyl-3-(7-methyl[1,2,4]- triazolo[1,5-b]pyridazin-6-yl)oxypropanesulfonamide (13) showed excellent anti-asthmatic activity. Compounds 13 may be of significant value in the treatment of asthma and other respiratory diseases. The structure-activity relationships in this series of compounds are discussed.

A series of new 1,4-benzoxazine derivatives (XI, XII) possessing (4-phenyl-1-piperazinyl)alkyl moieties at the 2-position and related compounds (XIII) were synthesized and tested for calcium antagonistic, calmodulin antagonistic and antihypertensive activities. Various compounds had in vitro calmodulin antagonistic activity superior or comparable to that of trifluoperazine. Among these compounds, tetrahydronaphtho[2,3-b] [1,4]oxazine derivatives such as 51, 53, 54, 58, 59, 60, 73 and 75 showed potent antihypertensive effects in spontaneously hypertensive rats. Optical isomers of 51 were also synthesized and evaluated biologically. No differences in biological activities were seen between the enantiomers.

A one-step synthesis of new pyrido [2,3-d] pyrimidine derivatives (III) was achieved through the Hantzsch synthesis using 6-aminouracils (I) as enamine nucleophiles

The carbon-14 labelled compound (5) of 2-[4-(diphenylmethyl)-1-piperazinyl]ethyl methyl (±)-1,4-dihydro-2,6-dimethyl-4-(m-nitrophenyl)-3,5-pyridinedicarboxylate dihydrochloride (CV-4093 (2HCl)) was synthesized for the study of its metabolism and distribution in test animals. Starting from the commercially available ethyl[3-14C]acetoacetate (1), 5 was prepared by a modified Hantzsch synthesis, in an overall radiochemical yield of 23.7%.

Enantiomeric (+)- and (-)-manidipine (1) dihydrochlorides were synthesized by the esterification of the optically active monocarboxylic acids (-)-6 and (+)-6, respectively. The absolute configurations, (S)-(+)-1 and (R)-(-)-1, were unambiguously determined by X-ray crystallographic analysis of (+)-7 derived from (-)-6. The (S)-(+)-1 was about 30 and 80 times as potent as the (R)-(-)-isomer in antihypertensive activity in spontaneously hypertensive rats (SHR), and in the radioligand binding assay using [3H]nitrendipine, respectively.