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Y Isomura

Publications and source records attributed to Y Isomura.

At least 37 records · Page 2Linked to original sources
PubMed1998

Studies on novel bone resorption inhibitors. II. Synthesis and pharmacological activities of fused aza-heteroarylbisphosphonate derivatives.

Two new series of fused aza-heteroarylbisphosphonates (5, 8), which are structurally quite different from incadronate (YM175), and related compounds were synthesized and evaluated for antiresorptive activity using a parathyroid hormone(PTH)-induced hypercalcemia model in rats (PIH model). Among these compounds, several exhibited more potent antiresorptive activity than pamidronate. In particular, [1-hydroxy-2-(imidazo[1,2-a]pyridin-3-yl)ethylidene]bisphosphonic acid (5b, minodronate) was 100-fold more potent than pamidronate in not only the PIH model, but also in an immobilization bone atrophy model in rats (DA model), and was selected for clinical development. The structure-activity relationships in these new series of bisphosphonates are discussed.

Animals↗
PubMed1998

Spiro-substituted piperidines as neurokinin receptor antagonists. II. Syntheses and NK2 receptor-antagonistic activities of N-[2-aryl-4-(spiro-substituted piperidin-1'-yl)butyl]carboxamides.

In the course of our research on spiro-compounds as neurokinin receptor antagonists, N-[2-aryl-4-(spiro-substituted piperidin-1'-yl)butyl]carboxamides were designed, based on YM-35375 (3) as a lead compound, and evaluated for NK2 receptor-antagonistic activities. Some derivatives inhibited the binding of radio-labeled neurokinin A to the NK2 receptor with IC50 values at the level of 10(-9) M. Among these compounds, (+/-)-1'-[4-(N-benzoyl-N-methylamino)-3- (3,4-dichlorophenyl)butyl]spiro[benzo[c]thiophene-1(3H), 4'-piperidine] 2-oxide (58, YM-38336) showed 10 times more potent NK2 receptor binding affinity than compound 3 (IC50 values of 8.9 and 84 nM, respectively). It showed more potent inhibitory activity (ID50 20 micrograms/kg (i.v.)) against [beta-Ala8]-NKA(4-10)-induced bronchoconstriction in guinea pigs than compound 3 (ID50 41 micrograms/kg (i.v.)). This compound was also effective intraduodenally in the same model, exhibiting an ID50 value of 0.41 microgram/kg.

Amides↗
PubMed1998

Spiro-substituted piperidines as neurokinin receptor antagonists. I. Design and synthesis of (+/-)-N-[2-(3,4-dichlorophenyl)-4-(spiro [isobenzofuran-1(3H),4'piperidin]-1'-yl)butyl]-N-methylbenzamide, YM-35375, as a new lead compound for novel neurokinin receptor antagonists.

Analysis of the structural requirements of compound 1 (SR48968), a potent NK2 receptor antagonist, revealed that the 4-phenyl group of the piperidine is essential for binding with the NK2 receptor and occupies an equatorial position. Energy calculation of a variety of substituted 4-phenyl piperidines revealed that spiro[isobenzofuran-1(3H),4'-piperidine] possesses a conformationally restricted equatorial phenyl group. Our compound 12 (YM-35375) possessing this spiro-substituted piperidine bound to the NK2 receptor with an IC50 value of 84 nM and to the NK1 receptor with an IC50 value of 710 nM. It showed more potent inhibitory activity (ID50 41 micrograms/kg (i.v.)) against [beta-Ala8]-NKA(4-10)-induced bronchoconstriction in guinea pigs than (+/-)-SR48968 (ID50 68 micrograms/kg (i.v.)). YM-35375 may be a new lead compound for novel NK2 receptor antagonists or NK1-NK2 dual antagonists.

Animals↗
PubMed1997

Studies on aromatase inhibitors. IV. Synthesis and biological evaluation of N,N-disubstituted-5-aminopyrimidine derivatives.

In order to study the potency of the 5-aminopyrimidine skeleton as an aromatase inhibitor, we synthesized various N,N-disubstituted-5-aminopyrimidine derivatives and evaluated their aromatase-inhibitory activity (in vitro) and their inhibitory activity on pregnant mare serum gonadotropin (PMSG)-induced estrogen synthesis (in vivo). Compounds with the fluoro-substituted benzyl group showed potent aromatase inhibition. Among them, 5-[(4-cyanophenyl)(3,5-difluorobenzyl)amino]pyrimidine (5w, YM553) was a highly potent compound with an IC50 value of 0.038 nM for aromatase from human placenta. Its inhibitory effect was approximately four times greater than that of YM511. In addition, YM553 was a weak inhibitor of other enzymes involved in steroid hormone synthesis. These results indicate that YM553, as well as YM511 (a 4-amino-4H-1,2,4-triazole derivative), is a promising agent for the treatment of estrogen-dependent diseases.

Animals↗
PubMed1997

Studies on aromatase inhibitors. II. Synthesis and biological evaluation of 1-amino-1H-1,2,4-triazole derivatives.

1-N,N-Disubstituted amino-1-H-1,2,4-triazole derivatives were prepared and evaluated for aromatase-inhibitory activity (in vitro) and for the inhibitory activity on pregnant mare serum gonadotropin (PMSG)-induced estrogen synthesis (in vivo). 1-N-para-Substituted benzylamino derivatives, having an electron-withdrawing group on the phenyl moiety, exhibited aromatase-inhibitory activity in vitro and in vivo. Among them, 1-[(4-nitrobenzyl)(4-nitrophenyl) amino]-1H,1,2,4-triazole (5b) was the most potent aromatase inhibitor. These 1-N-benzylamino derivatives also showed relatively strong inhibitory activity on aldosterone synthesis, indicating that the selectivity of these derivatives for aromatase inhibition was not sufficient in comparison with that of the 4-amino-4H-1,2,4-triazole derivatives.

Aldosterone↗
PubMed1997

Studies on aromatase inhibitors. III. Synthesis and biological evaluation of [(4-bromobenzyl)(4-cyanophenyl)amino]azoles and their azine analogs.

A series of [(4-bromobenzyl)(4-cyanophenyl)amino]azoles and their azine analogs, which have the side chain of the selective aromatase inhibitor YM511, were synthesized and evaluated for aromatase-inhibitory activity (in vitro) and for pregnant mare serum gonadotropin (PMSG)-induced estrogen synthesis inhibitory activity (in vivo). Among these aza-heterocycles, the pyrimidin-5-yl derivative (6a) was the most potent aromatase inhibitor and its in vitro inhibitory activity was comparable to that of YM511. Compound 6a also showed weak inhibitory activity on aldosterone synthesis. These data indicated that the pyrimidin-5-yl moiety is useful as a new azole fragment in place of the 4H-1,2,4-triazol-4-yl moiety of the aromatase inhibitor YM511.

Aldosterone↗
PubMed1996

Studies on aromatase inhibitors. I. Synthesis and biological evaluation of 4-amino-4H-1,2,4-triazole derivatives.

Various 4-N-substituted amino-4H-1,2,4-triazole derivatives were synthesized and evaluated for aromatase-inhibitory activity (in vitro) and for pregnant mare serum gonadotropin (PMSG)-induced estrogen synthesis-inhibitory activity (in vivo). The 4-(4-cyanophenyl) amino derivative and 4-(4-nitrophenyl)amino derivative, each possessing a strong electron-withdrawing group on the phenyl moiety, showed potent aromatase-inhibitory activity. Structure-activity relationship studies indicated that 4-[(4-bromobenzyl)(4-cyanophenyl)amino]-4H-1,2,4-triazole (5k, YM511) is a highly potent aromatase inhibitor with IC50 values of 0.4 and 0.12 nM in in vitro experiments using rat ovary and human placenta, respectively, and an in vivo ED50 of 0.002 mg/kg in rats on oral administration. YM511 was also a weak inhibitor of other steroid hormone synthesis enzymes. These data suggest that YM511 is a highly selective aromatase inhibitor and may be a useful agent for the treatment of estrogen-dependent diseases such as breast cancer.

Aldosterone↗
PubMed1995

The complete nucleotide sequence of odontoglossum ringspot virus (Cy-1 strain) genomic RNA.

The complete nucleotide sequence of the genomic RNA of odontoglossum ringspot virus Cy-1 strain (ORSV Cy-1) was determined using cloned cDNA. This sequence is 6611 nucleotides long containing four open reading frames, which correspond to 126 K, 183 K, 31 K, and 18 K proteins. Its genomic organization is similar to other tobamoviruses, TMV-V(vulgare), TMV-L (tomato strain), tobacco mild green mosaic virus (TMGMV) and cucumber green mottle mosaic virus (CGMMV). The 5' non-coding regions of ORSV Cy-1 is 62 nucleotides. The ORFs encoded a 126 K polypeptide and a 183 K read-through product in which helicase-sequence and polymerase-sequence motifs are found. The ORFs encoding the 126 K and 183 K proteins have 61% and 63% identities with those of TMV-V. The third ORF encoded a 31 K protein homologous to TMV cell-to-cell movement protein. It has 63% identities with that of TMV-V. The fourth ORF encoded an 18 K coat protein. The 5' non-coding region, which extends from base 1 to 62 has 2 G residues and a ribosome binding site (AUU). The 3' non-coding region, 414 nucleotides in length, is entirely different from that of other tobamoviruses.

Amino Acid Sequence↗
PubMed1993

Studies on novel bone resorption inhibitors. I. Synthesis and pharmacological activities of aminomethylenebisphosphonate derivatives.

A series of aminomethylenebisphosphonate derivatives was synthesized and evaluated for their antiresorptive activities using a parathyroid hormone (PTH)-induced hypercalcemia model in rats (PIH model). Among these compounds, (cycloheptylamino)methylenebis(phosphonic acid) (3j) was finally selected for further investigation, proving 10-fold as potent as pamidronate in the PIH model and an immobilization bone atrophy model in rats (DA model). The structure-activity relationships of this series of bisphosphonates are discussed.

Animals↗
PubMed1991

Molecular cloning, sequencing and expression in Escherichia coli of the odontoglossum ringspot virus coat protein gene.

The sequence of the 3'-terminal 1865 nucleotides of the genome of the tobamovirus odontoglossum ringspot virus (ORSV) was determined. This sequence contained two open reading frames (ORFs), 912 and 477 nucleotides long. The 912 nucleotide ORF has been identified as the cell-to-cell transport protein gene. The 477 nucleotide ORF was expressed in Escherichia coli, and the product was detected by antibodies specific for the coat protein of ORSV. The amino acid sequence of protein encoded by this ORF shares 84% similarity with the tobacco mosaic virus (TMV) (vulgare) coat protein. The 3'-terminal untranslated region of ORSV comprises 414 nucleotides, 210 nucleotides more than that of TMV (vulgare) RNA.

Amino Acid Sequence↗
PubMed1986

Stereoselectivity of a potent calcium antagonist, 1-benzyl-3-pyrrolidinyl methyl 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate.

Four enantiomers (3a-d) of the title compound, YM-09730 (3), were synthesized by the reaction of (-)- or (+)-5-(methoxycarbonyl)-2, 6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid (1a or 1b) with (S)- or (R)-1-benzyl-3-pyrrolidinol (2a or 2b). [3H]Nitrendipine binding affinity and coronary vasodilating activity of these compounds were evaluated. The absolute configuration of the most potent enantiomer (3a) with the longest duration was unequivocally determined to be (S)-1,4-dihydropyridine-C4 and (S)-pyrrolidine-C3 (S,S) by X-ray crystallographic study on 3a X HBr as well as 3a X HCl. The configuration of 1a corresponds to R, and the other enantiomers of 3 were respectively determined by chemical correlation. The potency order of the four enantiomers was (S,S)-3a greater than (S,R)-3b greater than (R,R)-3d greater than (R,S)-3c. Latent chiral characters of nifedipine derivatives with the identical ester groups were assigned by comparison of their puckering modes of 1,4-dihydropyridine (DHP) rings with those found in 3a X HCl or 3a X HBr. On the basis of the assignment, it has been revealed that the (S)-DHP nifedipine derivatives possess the synperiplanar carbonyl group at C5. The conformational restriction may be a factor causing stereoselectivity of antagonism.

Animals↗