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This study was designed to evaluate the effects of DS37001789, a novel and highly potent urotensin II (U-II) receptor (GPR14) antagonist, against mortality, hypertrophy, and cardiac dysfunction in pressure-overload hypertrophy by transverse aortic constriction (TAC) in mice. In addition, we analyzed the phenotype of GPR14 knockout (KO) mice after TAC induction to confirm the contribution of the U-II/GPR14 system. The oral administration of 0.2% DS37001789 to TAC mice for 12 weeks significantly ameliorated the mortality rate and 0.2% DS37001789 for 4 weeks significantly improved cardiac function by pressure-volume analysis. GPR14 expression was significantly upregulated in the left ventricle in the TAC mice treated with 0.2% DS37001789. Moreover, we confirmed that the significant amelioration of mortality was accomplished by the inhibition of cardiac enlargement and the improvement of cardiac function in GPR14 KO mice after TAC surgery. These results suggest that the U-II/GPR14 system contributes to the progression of heart failure and its blockade ameliorates the mortality via improved cardiac function. The U-II/GPR14 system may thus be an attractive target for treating heart failure with pathological cardiac hypertrophy and DS37001789 may be a novel therapeutic agent for heart failure in patients with pressure-overload conditions such as hypertension and aortic valve stenosis., Urotensin II; GPR14; Heart failure; Transverse aortic constriction; Biological sciences; Endocrinology; Diabetes; Health sciences; Cardiology; Cardiovascular system; Renal system; Pharmaceutical science; Biochemistry; Medicine; Physiology.

This study was designed to characterize the pharmacological profile of DS37001789, which is a structurally novel piperazine derivative that acts as urotensin II (U-II) receptor antagonist. DS37001789 inhibited [I]-U-II binding to human GPR14, U-II receptor, with an IC50 value 0.9 nM. Its potency was superior to that of ACT-058362, a nonpeptide U-II receptor antagonist whose IC50 was 120 nM. Human U-II-induced vascular contraction was blocked by DS37001789. The dose-response curve of DS37001789 in rats and monkeys did not show species differences, and it shifted to the right without any effects on the maximum vascular response. Moreover, orally administered DS37001789 dose-dependently prevented human U-II-induced blood pressure elevation in mice, and this effect was significant at dose and higher dose (30 and 100 mg/kg), and its potency was superior to that of ACT-058362 (100 mg/kg). These results suggest that DS37001789 is a highly potent U-II receptor antagonist both in vitro and in vivo, with no marked species difference. DS37001789 would be a useful tool to clarify the physiological roles of U-II/GPR14 system. In addition, it can serve as a novel therapeutic agent for diseases in which the U-II/GPR14 system is upregulated, such as hypertension, heart failure, renal dysfunction, and diabetes.

Urotensin II (U-II) has been found to be one of the most potent vasoconstrictor (Ames et al., 1999; Bohm et al., 2002) reported till date. U-II exerts its response via activation of a G-protein coupled receptor, Urotensin II receptor(UT). Binding of U-II to UT leads to an instant increase in the inositol phosphate turnover and intracellular Ca2+. Such an instant Ca2+ release and potent vasoconstriction exerted by U-II is expected to have an important role in the progression of cardiac diseases. We have previously shown that UT antagonist DS37001789 prevents U-II induced blood pressure elevation in mice (Nishi et al., 2019) in a dose dependent manner, with potent efficacy at 30 and 100 mg/kg. Further to this, we have also shown that DS37001789 ameliorates mortality in pressure-overload mice with heart failure (Nishi et al., 2020). We therefore conducted an extensive structure-activity relationship studies to identify molecules with superior efficacy. In the present manuscript, we report the identification of two potent, non-peptide small molecule antagonists of Urotensin II receptor (UT), RCI-0879 and RCI-0298 which blocked the action of U-II, both in vitro and in vivo. These molecules were found to be very potent in in vitro Ca2+ and radioligand binding assays using human and mouse UT over-expressing CHO cells. RCI-0879 and RCI-0298 also exhibited superior efficacy in in vivo mouse pressor response model using C57BL/6 mice, compared to our initial molecules (Nishi et al., 2019) and demonstrated ED50 values of 3.2 mg/kg and 6.8 mg/kg respectively. Our findings reported herewith, further strengthen our concept and belief in UT antagonization as a potential therapeutic approach for the management of chronic heart failure.

Amyloid beta peptide in the senile plaques of patients with Alzheimer's disease is considered to be responsible for the pathology of Alzheimer's disease. We have previously reported that 6-ethyl-N,N'-bis(3-hydroxyphenyl)[1,3,5]triazine-2,4-diamine, RS-0466, is capable of significantly inhibiting amyloid beta-induced cytotoxicity in HeLa cells. To determine various profiles of RS-0466, we investigated whether RS-0466 would enhance the neuroprotective effect of brain-derived neurotrophic factor on amyloid beta(1-42)-induced cytotoxicity in rat cortical neurones. Consistent with previous observations, brain-derived neurotrophic factor ameliorated amyloid beta(1-42)-induced cytotoxicity. Furthermore, co-application of RS-0466 enhanced the neuroprotective effect of brain-derived neurotrophic factor. RS-0466 also reversed amyloid beta(1-42)-induced decrease of brain-derived neurotrophic factor-triggered phosphorylated Akt. These results raise the possibility that RS-0466 or one of its derivatives has potential to enhance the neuroprotective effect of brain-derived neurotrophic factor, and could serve as a therapeutic agent for patients with Alzheimer's disease.

Progressive deposition of amyloid beta peptide in the senile plaques is a principal event in the neurodegenerative process of Alzheimer's disease. Several reports have demonstrated that amyloid beta is cytotoxic using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) as an indicator of viability in cells. With the MTT assay, we screened an in-house library to find compounds which suppress amyloid beta-induced inhibition of MTT reduction. We have previously reported that 6-ethyl-N,N'-bis(3-hydroxyphenyl)[1,3,5]triazine-2,4-diamine (named RS-0466), found in an in-house library, was capable of significantly inhibiting amyloid beta-induced cytotoxicity in HeLa cells. From further screening hits, we newly focused on 4-(7-hydroxy-2,2,4-trimethyl-chroman-4-yl)benzene-1,3-diol (named RS-4252), which show comparable potency to RS-0466 to ameliorate amyloid beta-induced cytotoxicity. Furthermore, RS-4252 reversed the decrease in phosphorylated Akt by amyloid beta. These results imply that RS-4252 or one of its derivatives has the potential to be a therapeutic for Alzheimer's disease patients, and that activation of Akt is at least in part involved in the effect.

A dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT), RS-1259 (4-[1S)-methylamino-3-(4-nitrophenoxy)]propylphenyl N,N-dimethylcarbamate (fumaric acid)1/2salt), was newly synthesized. RS-1259 simultaneously inhibited AChE and SERT in the brain following an oral administration in mice and rats. Actual simultaneous elevation of extracellular levels of 5-HT and ACh in the rat hippocampus was confirmed by microdialysis. The compound was as effective as SERT inhibitors such as fluoxetine and fluvoxamine in a 5-hydroxytryptophan-enhancing test in mice. Spatial memory deficits in the two-platform task of a water maze in aged rats were ameliorated by RS-1259 as well as donepezil. Both RS-1259 and donepezil increased the awake episodes in the daytime electroencephalogram of rats. Although RS-1259 was weaker than donepezil in enhancing central cholinergic transmission, as observed by ACh elevation in the hippocampus and memory enhancement in aged rats, the efficacy of RS-1259 on the consciousness level, which reflects the whole activity in the brain, was almost the same as that of donepezil. These results suggest that both cholinergic and serotonergic systems are involved in maintaining brain arousal and that a dual inhibitor of AChE and SERT may be useful for the treatment of cognitive disorders associated with reduced brain activity such as in Alzheimers disease.

Fibril formation of amyloid beta peptide (Abeta) is considered to be responsible for the pathology of Alzheimer's disease (AD). The Abeta fibril is formed by a protein misfolding process in which intermolecular beta-sheet interactions become stabilized abnormally. Thus, to develop potential anti-AD drugs, we screened an in-house library to find compounds which have a profile as a beta-sheet breaker. We searched for a beta-sheet breaker profile in an in-house library of approximately 113,000 compounds. From among the screening hits, we focused on N,N'-bis(3-hydroxyphenyl)pyridazine-3,6-diamine (named RS-0406), which had been newly synthesized in our laboratory. This compound (10-100 microg ml(-1)) was found to be capable of significantly inhibiting 25 microM Abeta(1-42) fibrillogenesis and, furthermore, disassembling preformed Abeta(1-42) fibrils in vitro. 3 We then investigated the effect of RS-0406 on 111 nM Abeta(1-42)-induced cytotoxicity in primary hippocampal neurons, and found that 0.3-3 microg ml(-1) RS-0406 ameliorates the cytotoxicity. Moreover, 3 microg ml(-1) RS-0406 reversed 1 micro M Abeta(1-42)-induced impairment of long-term potentiation in hippocampal slices. 4 In this study, we have succeeded in identifying RS-0406 which has potential to inhibit Abeta(1-42) fibrillogenesis, and to protect neurons against Abeta(1-42)-induced biological toxicity in vitro. These results suggest that RS-0406 or one of the derivatives could become a therapeutic agent for AD patients.

[formula: see text] The segment-coupling Prins cyclization avoids two of the problems common to other Prins cyclization protocols: side-chain exchange and partial racemization by reversible 2-oxonia Cope rearrangement. Model studies demonstrate the stereochemical fidelity of Prins cyclizations using alpha-acetoxy ethers compared with direct aldehyde-alcohol Prins reactions. Furthermore, we propose a mechanism for the racemization observed in some intermolecular Prins cyclizations. Two straightforward syntheses of optically pure (-)-centrolobine highlight the utility of Prins cyclizations.

Highly efficient acetylcholinesterase (AChE) and serotonin transporter (SERT) dual inhibitors, (S)-4 and (R)-13 were designed and synthesized on the basis of the hypothetical model of AChE active site. Both compounds showed potent inhibitory activities against AChE and SERT. [structure: see text]

A total synthesis of the neuritegenic agent, epolactaene has been achieved via a convergent approach in 14 steps from optically active lactaldehyde derivatives. The key steps include (i) the stereoselective aldol reaction between malonate ester enolate and α-alkoxy aldehyde (ii) diastereospecific lactonization of malonate ester (iii) E-selective Wittig reaction. The optical rotation was identical with that of the natural (+) -epolactaene, which establishes that the absolute configuration of natural (+) -epolactaene is (13R, 14R) definitively. Other several epoxy-γ-lactam compounds also synthesized which suggest this method would be general for organic synthesis.

A total synthesis of the novel neuritogenic agent (+)-epolactaene ((+)- 1 ) has been achieved via a convergent route that utilized epoxyamide 8 , C7–C11 fragment 7 , and C1–C6 Wittig reagent derived from phosphonium salt 19 followed by cyclization to form the lactam. The absolute configuration of natural epolactaene is definitively established as (13 R , 14 R ). Synthesis of (−)- 1 , the enantiomer of this natural epolactaene, is also described.

Enantioselective construction of the epoxy-γ-lactam moiety of epolactaene (1) was completed in 11 steps from (R)-lactaldehyde derivatives. Key steps include: (i) the stereoselective aldol reaction between (R)-lactaldehyde and malonate ester; (ii) diastereospecific lactonization of malonate ester derivative 10; (iii) cyclization of 16 to epoxy-γ-lactam derivative 2. Both enantiomers, (R,R)- 2 and (S,S)- 2 , were synthesized, and their optical rotations were compared with that of (+)-epolactaene (1). The results suggest that the absolute configuration of 1 is (13R,14R).

The optically active epoxy-γ-lactam moiety (−)- 4 of the B 2 selective bradykinin inhibitor L-755,807 1 was prepared from ( S )-aldehyde 7 via an anti selective aldol reaction as the key step.

Allyl sulfides containing a siloxy or hydroxy group at appropriate positions were successfully converted by two methods into two types of allylsilanes with almost complete stereo- and regiocontrol. In one method, an allyllithium was generated from the siloxy compound after which the silyl group migrated from oxygen to the carbanionic site. The reaction of 4-[[(trimethylsilyl)oxy]methyl]-3-methyl-2-cyclohexenyl phenyl sulfide with lithium di-tert-butylbiphenylide (LDBB) led to an exclusive formation of (1R * ,2R * )-2-methyl-2-(trimethylsilyl)-3-cyclohexene-1-methanol. The second method involved the silylation of an oxyanion-carbanion

Allyl sulfides containing a siloxy or hydroxy group at appropriate positions were successfully converted by two methods into two types of allylsilanes with almost complete stereo- and regiocontrol. In one method, an allyllithium was generated from the siloxy compound after which the silyl group migrated from oxygen to the carbanionic site. The reaction of 4-[[(trimethylsilyl)oxy]methyl]-3-methyl-2-cyclohexenyl phenyl sulfide with lithium di-tert-butylbiphenylide (LDBB) led to an exclusive formation of (1R * ,2R * )-2-methyl-2-(trimethylsilyl)-3-cyclohexene-1-methanol. The second method involved the silylation of an oxyanion-carbanion

Stereoselective aldol reactions between the lithium enolate of tert-butyl malonate and various α-alkoxy aldehydes in the presence of zinc chloride gave anti-1,2-diols in high yields; 2-trityloxypropanal yielded the syn-1,2-diol under the same conditions.

A total synthesis of the novel neuritogenic agent (+)-epolactaene ((+)- 1 ) has been achieved via a convergent route that utilized epoxyamide 8 , C7–C11 fragment 7 , and C1–C6 Wittig reagent derived from phosphonium salt 19 followed by cyclization to form the lactam. The absolute configuration of natural epolactaene is definitively established as (13 R , 14 R ). Synthesis of (−)- 1 , the enantiomer of this natural epolactaene, is also described.

Enantioselective construction of the epoxy-γ-lactam moiety of epolactaene (1) was completed in 11 steps from (R)-lactaldehyde derivatives. Key steps include: (i) the stereoselective aldol reaction between (R)-lactaldehyde and malonate ester; (ii) diastereospecific lactonization of malonate ester derivative 10; (iii) cyclization of 16 to epoxy-γ-lactam derivative 2. Both enantiomers, (R,R)- 2 and (S,S)- 2 , were synthesized, and their optical rotations were compared with that of (+)-epolactaene (1). The results suggest that the absolute configuration of 1 is (13R,14R).

On treating with LDBB, 2-substituted 3-phenylthioalkyl silyl ethers were converted to the corresponding 3-silylated alkanols with high anti selectivity. Application to silyl ethers containing allylic sulfide moieties provided a useful methodology for the regio- and stereo-defined synthesis of allylsilanes.

The synthesis and absolute configuration of SCH 351448, an interesting ionophoric natural product, are reported herein. Mukaiyama aldol-Prins and segment-coupling Prins reactions were employed to construct the constituent tetrahydropyrans of SCH 351448. Efforts to assemble the C2-symmetric core of the natural product by a templated olefin metathesis strategy are described, however, a stepwise fragment assembly was ultimately utilized to complete the target molecule.

Alzheimer's disease (AD) has been treated with acetylcholinesterase (AChE) inhibitors such as donepezil. However, the clinical usefulness of AChE inhibitors is limited mainly due to their adverse peripheral effects. Depression seen in AD patients has been treated with serotonin transporter (SERT) inhibitors. We considered that combining SERT and AChE inhibition could improve the clinical usefulness of AChE inhibitors. In a previous paper, we found a potential dual inhibitor, 1, of AChE (IC50=101 nM) and SERT (IC50=42 nM), but its AChE inhibition activity was less than donepezil (IC50=10 nM). Here, we report the conformationally restricted (R)-18a considerably enhanced inhibitory activity against AChE (IC50=14 nM) and SERT (IC50=6 nM).

[reaction: see text] A new version of the Mukaiyama aldol-Prins (MAP) cyclization has been developed. Unsaturated enol ethers such as 3 were found to couple with aldehydes in the presence of TiBr(4) to give 4-bromotetrahydropyran products. This cascade reaction sequence leads to the formation of two new carbon-carbon bonds, a ring, and three new stereogenic centers. We expect this reaction to be a powerful new tool in synthesis.

Progressive deposition of amyloid beta peptide in the senile plaques is a principal event in the neurodegenerative process of Alzheimer's disease. Several reports have demonstrated that amyloid beta is cytotoxic using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) as an indicator of viability in cells. With the MTT assay, we screened an in-house library to find compounds which suppress amyloid beta-induced inhibition of MTT reduction. We have previously reported that 6-ethyl-N,N'-bis(3-hydroxyphenyl)[1,3,5]triazine-2,4-diamine (named RS-0466), found in an in-house library, was capable of significantly inhibiting amyloid beta-induced cytotoxicity in HeLa cells. From further screening hits, we newly focused on 4-(7-hydroxy-2,2,4-trimethyl-chroman-4-yl)benzene-1,3-diol (named RS-4252), which show comparable potency to RS-0466 to ameliorate amyloid beta-induced cytotoxicity. Furthermore, RS-4252 reversed the decrease in phosphorylated Akt by amyloid beta. These results imply that RS-4252 or one of its derivatives has the potential to be a therapeutic for Alzheimer's disease patients, and that activation of Akt is at least in part involved in the effect.

We have designed and synthesized a dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT) as a novel class of treatment drugs for Alzheimer's disease on the basis of a hypothetical model of the AChE active site. Dual inhibitions of AChE and SERT would bring about greater therapeutic effects than AChE inhibition alone and avoid adverse peripheral effects caused by excessive AChE inhibition. Compound ( S )- 6j exhibited potent inhibitory activities against AChE (IC 50 =101 nM) and SERT (IC 50 =42 nM). Furthermore, ( S )- 6j showed inhibitory activities of both AChE and SERT in mice brain following oral administration.

beta-Amyloid peptide is the principal protein in the senile plaques of Alzheimer's disease and is considered to be responsible for the pathology of Alzheimer's disease. Several studies have shown that beta-amyloid is cytotoxic, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) as an indicator of viability in cells. Utilizing the MTT assay, we screened an in-house library to find compounds that suppress beta-amyloid-induced inhibition of MTT reduction. From among the screening hits, we focused on 6-ethyl-N,N'-bis(3-hydroxyphenyl)[1,3,5]triazine-2,4-diamine (named RS-0466), which had been newly synthesized in our laboratory. This compound was found to be capable of significantly inhibiting beta-amyloid-induced cytotoxicity in HeLa cells and of reversing the decrease of phosphorylated Akt induced by beta-amyloid. Furthermore, RS-0466 reversed the beta-amyloid-induced impairment of long-term potentiation in rat hippocampal slices. These results raise the possibility that RS-0466 or its derivatives have potential as a therapeutic agent for Alzheimer's disease patients, and its effect is at least in part mediated by activation of Akt.

Fibril formation of amyloid beta peptide (Abeta) is considered to be responsible for the pathology of Alzheimer's disease (AD). The Abeta fibril is formed by a protein misfolding process in which intermolecular beta-sheet interactions become stabilized abnormally. Thus, to develop potential anti-AD drugs, we screened an in-house library to find compounds which have a profile as a beta-sheet breaker. We searched for a beta-sheet breaker profile in an in-house library of approximately 113,000 compounds. From among the screening hits, we focused on N,N'-bis(3-hydroxyphenyl)pyridazine-3,6-diamine (named RS-0406), which had been newly synthesized in our laboratory. This compound (10-100 microg ml(-1)) was found to be capable of significantly inhibiting 25 microM Abeta(1-42) fibrillogenesis and, furthermore, disassembling preformed Abeta(1-42) fibrils in vitro. 3 We then investigated the effect of RS-0406 on 111 nM Abeta(1-42)-induced cytotoxicity in primary hippocampal neurons, and found that 0.3-3 microg ml(-1) RS-0406 ameliorates the cytotoxicity. Moreover, 3 microg ml(-1) RS-0406 reversed 1 micro M Abeta(1-42)-induced impairment of long-term potentiation in hippocampal slices. 4 In this study, we have succeeded in identifying RS-0406 which has potential to inhibit Abeta(1-42) fibrillogenesis, and to protect neurons against Abeta(1-42)-induced biological toxicity in vitro. These results suggest that RS-0406 or one of the derivatives could become a therapeutic agent for AD patients.

[reaction--see text] The 2-oxonia Cope rearrangement is undetectable in typical Prins cyclization reactions. We have investigated the Cope rearrangement in a Prins cyclization reaction using a competitive reduction of the oxocarbenium ion intermediate, and a racemization reaction mediated by the rearrangement. In our unactivated substrate, the 2-oxonia Cope rearrangement was much faster than Prins cyclization. An enantioselective allyl transfer reaction also was developed using a 2-oxonia Cope rearrangement.

Stereoselective aldol reactions between the lithium enolate of tert-butyl malonate and various α-alkoxy aldehydes in the presence of zinc chloride gave anti-1,2-diols in high yields; 2-trityloxypropanal yielded the syn-1,2-diol under the same conditions.