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Versatile intramolecular Friedel–Crafts reaction of 1-(2-iso-cyanatoethyl)benzene derivatives was established by using trifluoromethanesulfonic acid as a catalyst and solvent. This methodology has been applied to the substrates with strong electron-withdrawing group. Furthermore, using the Friedel–Crafts product as a common synthetic intermediate, synthesis of several isoquinoline derivatives was also successful.

Versatile intramolecular Friedel–Crafts reaction of 1-(2-iso-cyanatoethyl)benzene derivatives was established by using trifluoromethanesulfonic acid as a catalyst and solvent. This methodology has been applied to the substrates with strong electron-withdrawing group. Furthermore, using the Friedel–Crafts product as a common synthetic intermediate, synthesis of several isoquinoline derivatives was also successful.

Chemical modification has been performed on an orally bioavailable and potent CCR5 antagonist, sulfoxide compound 4, mainly focusing on replacement of the [6,7]-fused 1-benzazepine nucleus. We designed, synthesized, and evaluated the biological activities of ring-expanded [6,8]-, [6,9]-, and [6,10]-fused compounds containing S-sulfoxide moieties, which led to the discovery of 1-benzazocine and 1-benzazonine compounds that exhibited potent inhibitory activities (equivalent to compound 4) in a binding assay. In addition, 1-benzazocine compounds possessing the S-sulfoxide moiety ((S)-(-)-5a,b,d,e) showed greater potency than compound 4 in a fusion assay. From further investigation in a multi-round infection assay, it was found that 1-isobutyl-1-benzazocine compound (S)-(-)-5b, containing the S-{[(1-propyl-1H-imidazol)-5-yl]methyl}sulfinyl group, showed the most potent anti-HIV-1 activity (IC90=0.81 nM, in MOLT4/CCR5 cells). Compound (S)-(-)-5b (TAK-652) also inhibited the replication of six macrophage-tropic (CCR5-using or R5) HIV-1 clinical isolates in peripheral blood mononuclear cells (PBMCs) (mean IC90=0.25 nM). It was also absorbed after oral administration in rats, dogs, and monkeys and was thus selected as a clinical candidate. The synthesis and biological activity of the 1-benzazocine compound (S)-(-)-5b and its related derivatives are described.

In order to develop orally active CCR5 antagonists, we investigated 1-benzoxepine derivatives containing new polar substituents, such as phosphonate, phosphine oxide or pyridine N-oxide moieties, as replacements for the previously reported quaternary ammonium moiety. Among these compounds, the 2-(alpha-hydroxybenzyl)pyridine N-oxide 5e exhibited moderate CCR5 antagonistic activity and had an acceptable pharmacokinetic profile in rats. Subsequent chemical modification was performed and compound (S)-5f possessing the (S)-configuration hydroxy group was found to be more active than the (R)-isomer. Replacement of the 1-benzoxepine ring with a 4-methylphenyl group by a 1-benzazepine ring with a 4-[2-(butoxy)ethoxy]phenyl group enhanced the activity in the binding assay. In addition, introduction of a 3-trifluoromethyl group on the phenyl group of the anilide moiety led to greatly increased activity in the HIV-1 envelope-mediated membrane fusion assay. In particular, compound (S)-5s showed the most potent CCR5 antagonistic activity (IC(50)=7.2 nM) and inhibitory effect (IC(50)=5.4 nM) in the fusion assay, together with good pharmacokinetic properties in rats.

We investigated the inhibitory effects of a non-acylguanidine Na+-H+ exchange (NHE) inhibitor, T-162559 ((5E,7S)-[7-(5-fluoro-2-methylphenyl)-4-methyl-7,8-dihydro-5(6H)-quinolinylideneamino] guanidine dimethanesulphonate), on NHE-1, and its cardioprotective effect against ischaemia and reperfusion injury in rats and rabbits. T-162559 inhibited human platelet NHE-1 in a concentration-dependent manner, with an IC50 value of 13±3 nmol l−1, making it 16 and three times more potent than cariporide IC50: 209±75 nmol l−1, P

We established a human immunodeficiency virus type 1 (HIV-1) envelope (Env)-mediated membrane fusion assay and examined the small-molecule CCR5 antagonist TAK-779 and its derivatives for their inhibitory effects on HIV-1 Env-mediated membrane fusion and viral replication. The membrane fusion assay is based on HIV-1 long terminal repeat-directed β- d -galactosidase reporter gene expression in CD4- and CCR5-expressed HeLa (MAGI-CCR5) cells after cocultivation with effector 293T cells expressing HIV-1 Env. Inhibition of HIV-1 replication was also determined in MAGI-CCR5 cells infected with the corresponding cell-free HIV-1. TAK-779 effectively suppressed R5 HIV-1 (strain JR-FL) Env-mediated membrane fusion as well as viral replication. Its 50% inhibitory concentrations (IC 50 s) for membrane fusion and viral replication were 0.87 ± 0.11 and 1.4 ± 0.1 nM, respectively. These values corresponded well to the IC 50 for 125 I-RANTES (regulated on activation, T cell expressed, and secreted) binding to CCR5 (1.4 nM). The inhibitory effects of 18 TAK-779 derivatives on membrane fusion differed from one compound to another. However, there was a close correlation among their inhibitory effects on membrane fusion, viral replication, and RANTES binding. The correlation coefficient between their IC 50 s for membrane fusion and viral replication was 0.881. Furthermore, since this assay depends on Env expressed in the effector cells, it is also applicable to the evaluation of CXCR4 antagonists. These results indicate that the HIV-1 Env-mediated membrane fusion assay is a useful tool for the evaluation of entry inhibitors.

Er: YAGレーザーを, エナメル小柱あるいは象牙細管の走行に対して平行および直角に照射し, 照射面の形態学的特徴と照射方向との関連性について検討した. 大阪歯科大学歯科保存学講座および口腔外科学講座にて採取した新鮮抜去臼歯を, 歯科用ディスクによって注水下で近遠心的に2分割し, 耐水ペーパー (#600番) で研磨仕上げを行った. Er: YAGレーザー機器としてはアーウィン (モリタ社・ホヤ社製) を用いた. 照射方向は, エナメル小柱あるいは象牙細管の走行に対して平行 (平行照射), および直角 (直角照射) とした. 照射条件は, 180mJ, 1ppsとし, エナメル質においては2秒間, 象牙質においては1秒の照射とした. レーザー照射したエナメル質面・象牙質面, および照射による切削片を通法によって金蒸着し, SEM観察した. エナメル質への直角照射においては花咲き状の像が観察され, 平行照射ではロッド状の像が認められた. 切削片は, 平行照射の方が垂直照射に比べて大きかった. この理由は, エナメル小柱および小柱間質よりも小柱鞘の方が水分含有量が多いため, 水に対する吸収率が高いEr: YAGレーザーの照射によって小柱鞘が選択的に破壊され, 直 角照射よりも平行照射の場合が, 破壊が大きくなったものと考えられた. 一方, 象牙質面においては, 照射方向の違いによる形態学的特徴の差はあまり見られなかった. これは, エナメル質に比べて象牙質の水の含有量が十数倍多いため, 照射方向による切削の異なりに差が現われなかったものと考えられた.

We were interested in RCS (rabbit aorta contracting substance) and SRS-A (slow reacting substance of anaphylaxis) and their involvement in human bronchial asthma. When we started our anti-asthmatic drug research in the 1970's. We synthesized a lot of chemical compounds and eventually discovered that AA-861 inhibited the generation of SRS-A from the lung tissue of actively sensitized guinea pigs. AA-861 was found to be a potent 5-lipoxygenase inhibitor. This compound reduced experimental allergic asthma in guinea pigs, but it is easily metabolized in the body. More recently, we found a novel compound, AA-2414 (seratrodast), which is not metabolized in the body. AA-2414 proved to be not a 5-lipoxygenase inhibitor, but a thromboxane A2 (TXA2) receptor antagonist. Seratrodast is the first receptor antagonist that is being developed as an anti-asthmatic drug. Seratrodast inhibits both immediate-, late asthmatic responses in guinea pigs, and also reduces airway hyperresponsiveness in dogs. The anti-asthmatic action of seratrodast in animal models indicates that the drug should be of use in the treatment of human asthmatics. In clinical studies, seratrodast showed a marked effect to improve clinical parameters in bronchial asthma. It is also reported that seratrodast is free from harmful aftereffects. Clinical trials are under way in the US.

Enantiomers of four potent nonprostanoid thromboxane A2 (TXA2) receptor antagonists, (+/-)-7-(4-fluorophenyl)-7-(2-hydroxyphenyl)heptanoic acids (1-4), were synthesized stereoselectively by direct ortho-alkylation of phenols under modified Mitsunobu conditions. The reaction of 5 eq of phenols (6a-c) with 1 eq of (S)- or (R)-methyl 7-(4-fluorophenyl)-7-hydroxyheptanoate ((S)- or (R)-7) afforded ortho-alkylated phenol derivatives (6a-c) enantioselectively in 33 to 42% chemical yield and 90 to 93% ee. In these compounds, the (R)-enantiomers (1-4) exhibited potent TXA2 receptor antagonistic activity and the (S)-isomer (3) was much less active. In particular, compound (R)-3 strongly inhibited U-46619-induced human platelet aggregation (IC50 = 48 nM), and also showed a very potent inhibitory effect with a minimum effective dose (MED) of 0.3 mg/kg (p.o.) on U-46619-induced bronchoconstriction in guinea pigs.

Vinyl vicinal tricarbonyls undergo tandem addition of Wittig reagents or compounds containing activated methylene groups to form highly functionalized derivatives of cyclopentenones or cyclopentanones.

The antihypertensive and cardiovascular properties of a new potassium channel opener, TCV-295, were studied in rats and dogs. In conscious, spontaneously hypertensive rats (SHR), TCV-295 (0.03-1 mg/kg orally, p.o.) reduced blood pressure (BP) dose dependently with slow onset of action. The antihypertensive effects induced by TCV-295 lasted much longer than those of levcromakalim and nisoldipine, and the reflex tachycardia it evoked was less marked than that evoked by these drugs as compared at doses showing similar maximal hypotensive effects. Glibenclamide (30 mg/kg intravenously, i.v.) inhibited the TCV-295-induced BP decrease in anesthetized rats. In a 4-week chronic dosing study in SHR, TCV-295 (0.3 mg/kg/day p.o.) produced neither potentiation nor tolerance to its antihypertensive action and no rebound hypertension occurred when drug treatment was discontinued. In anesthetized normotensive dogs, TCV-295 (4.5 micrograms/kg/min i.v.) induced BP reductions accompanied by reductions in systemic vascular resistance. TCV-295 also reduced resistances of the coronary, vertebral, mesenteric, and renal vascular beds, and the most marked effect was observed in the coronary vasculature. Myocardial O2 consumption was reduced by TCV-295, possibly owing to afterload decrease. These results suggest that TCV-295 has a desirable profile for an antihypertensive agent.

Vinyl vicinal tricarbonyls undergo tandem addition of Wittig reagents or compounds containing activated methylene groups to form highly functionalized derivatives of cyclopentenones or cyclopentanones.

ortho-Substituted phenol derivatives with high optical purity have been obtained directly by Mitsunobu reaction between an appropriate phenol and an optically active benzyl alcohol. In this reaction, the chemical yield was well balanced with the optical purity of the ortho-substituted compound when 5 equiv. of phenol was allowed to react with 1 equiv. of alcohol in a solvent such as dichloroethane or toluene. In addition, it was confirmed by an X-ray analysis of the product that stereochemical inversion of the asymmetric centre took place in this reaction, as well as the usual Mitsunobu reaction. This reaction is useful in the preparation of optically active phenol derivatives possessing a diarylmethane moiety.

A new series of 1, 3-benzoxazine derivatives with a 2-pyridine 1-oxide group at C4 was designed to explore novel K+ channel openers. Synthesis swas carried out by using a palladium(0)-catalyzed carbon-carbon bond formation reaction of imino-triflates with organozinc reagents and via a new one-pot 1, 3-benzoxazine skeleton formation reaction of benzoylpyridines. The compounds were tested for vasorelaxant activity in tetrathylammonium choloride (TEA) and BaCl2-induced and high KCl-induced contraction of rat aorta to identify potential K+ channel openers, and also for oral hypotensive effects in spontaneously htypertensive rats. An electron-withdrawing group with the proper shape at C6 and a methyl or halogeno group at C7 of the 1, 3-benzoxazine nucleus were required for the development of opticmal vasorelaxant and hypotensive activity. In particular, 2-(6-bromo-7-chloro-2, 2-dimethyl-2H-1, 3-benzoxazin-4-yl)pyridine 1-oxide (71) showed more potent vasorelatzant activity (EC50=0.14 μM) against TEA and BaCl2-induced contraction and longer-lasting hypotensive effects than cromakalim (1).

Enantiomers of four potent nonprostanoid thromboxane A2 (TXA2) receptor antagonists, (+/-)-7-(4-fluorophenyl)-7-(2-hydroxyphenyl)heptanoic acids (1-4), were synthesized stereoselectively by direct ortho-alkylation of phenols under modified Mitsunobu conditions. The reaction of 5 eq of phenols (6a-c) with 1 eq of (S)- or (R)-methyl 7-(4-fluorophenyl)-7-hydroxyheptanoate ((S)- or (R)-7) afforded ortho-alkylated phenol derivatives (6a-c) enantioselectively in 33 to 42% chemical yield and 90 to 93% ee. In these compounds, the (R)-enantiomers (1-4) exhibited potent TXA2 receptor antagonistic activity and the (S)-isomer (3) was much less active. In particular, compound (R)-3 strongly inhibited U-46619-induced human platelet aggregation (IC50 = 48 nM), and also showed a very potent inhibitory effect with a minimum effective dose (MED) of 0.3 mg/kg (p.o.) on U-46619-induced bronchoconstriction in guinea pigs.

We were interested in RCS (rabbit aorta contracting substance) and SRS-A (slow reacting substance of anaphylaxis) and their involvement in human bronchial asthma. When we started our anti-asthmatic drug research in the 1970's. We synthesized a lot of chemical compounds and eventually discovered that AA-861 inhibited the generation of SRS-A from the lung tissue of actively sensitized guinea pigs. AA-861 was found to be a potent 5-lipoxygenase inhibitor. This compound reduced experimental allergic asthma in guinea pigs, but it is easily metabolized in the body. More recently, we found a novel compound, AA-2414 (seratrodast), which is not metabolized in the body. AA-2414 proved to be not a 5-lipoxygenase inhibitor, but a thromboxane A2 (TXA2) receptor antagonist. Seratrodast is the first receptor antagonist that is being developed as an anti-asthmatic drug. Seratrodast inhibits both immediate-, late asthmatic responses in guinea pigs, and also reduces airway hyperresponsiveness in dogs. The anti-asthmatic action of seratrodast in animal models indicates that the drug should be of use in the treatment of human asthmatics. In clinical studies, seratrodast showed a marked effect to improve clinical parameters in bronchial asthma. It is also reported that seratrodast is free from harmful aftereffects. Clinical trials are under way in the US.

The first small-molecule CCR5 antagonist, TAK-779, could not be developed as an anti-human immunodeficiency virus type (anti-HIV-1) agent because of its poor oral bioavailability. TAK-652 is an orally bioavailable TAK-779 derivative with potent anti-HIV-1 activity. TAK-652 inhibited the binding of RANTES (regulated on activation, normal T-cell expressed and secreted), macrophage inflammatory protein 1α (MIP-1α), and MIP-1β to CCR5-expressing cells at nanomolar concentrations. TAK-652 could also suppress the binding of monocyte chemotactic protein 1 (MCP-1) to CCR2b-expressing cells. However, its inhibitory effect on ligand binding to other chemokine receptors was limited. TAK-652 was active against CCR5-using (R5) HIV-1 but totally inactive against CXCR4-using (X4) HIV-1. The compound was active against R5 HIV-1 clinical isolates containing reverse transcriptase and protease inhibitor-resistant mutations, with a mean 50% effective concentration (EC 50 ) and EC 90 of 0.061 and 0.25 nM, respectively. In addition, recombinant R5 viruses carrying different subtype (A to G) envelope proteins were equally susceptible to TAK-652. A single oral administration of TAK-652 up to 100 mg was safe and well tolerated in humans. The compound displayed favorable pharmacokinetics, and its plasma concentration was 7.2 ng/ml (9.1 nM) even 24 h after the administration of 25 mg. Thus, TAK-652 is a promising candidate as a novel entry inhibitor of HIV-1.

In order to develop orally active CCR5 antagonists, 1-propyl- or 1-isobutyl-1-benzazepine derivatives containing a sulfoxide moiety have been designed, synthesized, and evaluated for their biological activities. Sulfoxide compounds containing a 2-pyridyl group were first investigated, which led to discovering that the presence of a methylene group between the sulfoxide moiety and 2-pyridyl group was necessary for increased inhibitory activity in a binding assay. After further chemical modification, it was found that replacement of the pyridyl group with an imidazolyl or 1,2,4-triazolyl group enhanced activity in the binding assay and that S-sulfoxide compounds were more active than R-isomers. Particularly, compounds (S)-4r, (S)-4s, and (S)-4w exhibited highly potent CCR5 antagonistic activities (IC50=1.9, 1.7, 1.6 nM, respectively) and inhibitory effects (IC50=1.0, 2.8, 7.7 nM, respectively) in the HIV-1 envelope mediated membrane fusion assay, together with good pharmacokinetic properties in rats. In addition, we established the synthesis of (S)-4r and (S)-4w by asymmetric oxidation with titanium-(S)-(-)-1,1'-bi-2-naphthol complex.

The search for orally active CCR5 antagonists was performed by chemical modification of the 1-benzothiepine 1,1-dioxide 3 and 1-benzazepine 4 lead compounds containing a tertiary amine moiety. Replacement of methyl group with a 2-(C 2 - 4 alkoxy)ethoxy group at the 4-position on the 7-phenyl group of the 1-benzothiepine ring resulted in both enhanced activity and significant improvement in the pharmacokinetic properties upon oral administration in rats. Introduction of C 2 - 4 alkyl, phenyl or (hetero)arylmethyl groups as the 1-substituent on the 1-benzazepine ring together with the 2-(butoxy)ethoxy group led to further increase of activity. Among the 1-benzazepine derivatives, the isobutyl (6i), benzyl (60) or 1-methylpyrazol-4-ylmethyl (6s) compounds were found to exhibit highly potent inhibitory effects, equivalent to the injectable CCR5 antagonist 1, in the HIV-1 envelopemediated membrane fusion assay. In particular, compound 6s showed the most potent CCR5 antagonistic activity (IC 5 0 =2.7 nM) and inhibitory effect (IC 5 0 =1.2 nM) on membrane fusion, together with good pharmacokinetic properties in rats. The synthesis of 1-benzothiepine 1,1-dioxide and 1-benzazepine derivatives and their biological activity are described.

Quaternary ammonium benzocycloheptene compound 1 has previously been reported as a clinical candidate for an injectable CCR5 antagonist. In order to develop an orally active CCR5 antagonist, derivatives of tertiary amine benzocycloheptene 2, the chemical precursor to 1, were investigated. The benzocycloheptene ring was converted to benzothiepine and benzazepine rings and it was found that these changes could enhance the potency of tertiary amine derivatives. In particular, the 1-benzothiepine-1,1-dioxide 11b and the N-methyl-1-benzazepine 18 showed increased activity and good preliminary pharmacokinetic properties. The synthesis of 1-benzothiepine and 1-benzazepine derivatives and their activity are described.

In the course of our research into new types of non-acylguanidine Na(+)/H(+) exchanger (NHE) inhibitors, we designed and synthesized aryl-fused tetrahydropyranylidene and cyclohexylidene aminoguanidine derivatives I (X = O, CH(2)), which were tested for their inhibitory effects on rat platelet NHEs. After optimization, we found that the S isomer of tetrahydroquinoline derivatives that possess a methyl group in the 4-position and a halogen or methyl group in the o-position of Ar(2) exhibited high inhibitory activity. In these compounds, (5E,7S)-[[7-(5-fluoro-2-methylphenyl)-4-methyl-7,8-dihydro-5(6H)-quinolinylidene]amino]guanidine dimethanesulfonate (18, T-162559) was found to be a potent inhibitor of both rat and human platelet NHEs, with IC(50) values of 14 and 13 nM, respectively. Furthermore, in a rat myocardial infarction model in vivo (1 h ischemia-24 h reperfusion), 18 (0.1 mg/kg, intravenously administered 5 min or 2 h before coronary occlusion) showed significant activity (33% or 23% inhibition, respectively). These results suggested that 18 may exhibit a potent and long-lasting protective activity against cardiac injuries induced by ischemia-reperfusion.

We isolated Na+/H+ exchanger (NHE)-deficient Chinese hamster ovary (CHO-K1) cells stably expressing human NHE isoforms (hNHE1, hNHE2 and hNHE3) and established an assay system for measuring their Na+/H+ exchange activity by monitoring intracellular pH alterations. Using this assay system, we demonstrated that the acylguanidine derivatives, cariporide and eniporide, cause selective inhibition of hNHE1 (IC50 value of 30 nM for cariporide, IC50 value of 4.5 nM for eniporide). Furthermore, we found that a novel synthetic aminoguanidine derivative, T-162559 ((5E,7S)-[7-(5-fluoro-2-methylphenyl)-4-methyl-7,8-dihydro-5(6H)-quinolinylideneamino] guanidine dimethanesulfonate), causes a selective inhibition of hNHE1 with more potent activity than cariporide and eniporide (IC50 value of 0.96 nM). This compound did not affect Na+/HCO3- cotransport and Na+/Ca2+ exchange.

The search for new small-molecule CCR5 antagonists by high-throughput screening (HTS) of the Takeda chemical library using [(125)I]RANTES and CHO/CCR5 cells led to the discovery of lead compounds (A, B) with a quaternary ammonium or phosphonium moiety, which were synthesized to investigate new MCP-1 receptor antagonists. A series of novel anilide derivatives 1 with a quaternary ammonium moiety were designed, synthesized, and tested for their CCR5 antagonistic activity. Through the optimization of lead compounds, we have found N,N-dimethyl-N-[4-[[[2-(4-methylphenyl)-6, 7-dihydro-5H-benzocyclohepten-8-yl]carbonyl]amino]benzyl]tetrahydr o-2 H-pyran-4-aminium chloride (1r, TAK-779) as a highly potent and selective nonpeptide CCR5 antagonist with a IC(50) value of 1.4 nM in the binding assay. Compound 1r also inhibited the replication of macrophage (M)-tropic HIV-1 (Ba-L strain) in both MAGI-CCR5 cells and PBMCs with EC(50) values of 1.2 and 3.7 nM, respectively. The synthesis and structure-activity relationships of 1r and its related compounds are detailed.

The β-chemokine receptor CCR5 is considered to be an attractive target for inhibition of macrophage-tropic (CCR5-using or R5) HIV-1 replication because individuals having a nonfunctional receptor (a homozygous 32-bp deletion in the CCR5 coding region) are apparently normal but resistant to infection with R5 HIV-1. In this study, we found that TAK-779, a nonpeptide compound with a small molecular weight (Mr531.13), antagonized the binding of RANTES (regulated on activation, normal T cell expressed and secreted) to CCR5-expressing Chinese hamster ovary cells and blocked CCR5-mediated Ca2+signaling at nanomolar concentrations. The inhibition of β-chemokine receptors by TAK-779 appeared to be specific to CCR5 because the compound antagonized CCR2b to a lesser extent but did not affect CCR1, CCR3, or CCR4. Consequently, TAK-779 displayed highly potent and selective inhibition of R5 HIV-1 replication without showing any cytotoxicity to the host cells. The compound inhibited the replication of R5 HIV-1 clinical isolates as well as a laboratory strain at a concentration of 1.6–3.7 nM in peripheral blood mononuclear cells, though it was totally inactive against T-cell line-tropic (CXCR4-using or X4) HIV-1.

The search for novel K+ channel openers with a non-benzopyran skeleton, unlike cromakalim, led to the discovery of a new series of (Z)-2-(alpha-alkoxyimino)benzylpryridine derivatives. Synthesis was achieved by using a (Z)-dominant condensation reaction of benzoylpyridines with O-alkylhydroxylamines, followed by m-chloroperbenzoic acid (m-CPBA) oxidation. The compounds were tested for their vasorelaxant activity in tetraethylammonium chloride (TEA) and BaCl2- and high KCl-induced contraction of rat aorta to identify potential K+ channel openers, and also for their effects on the coronary blood flow (CBF) after intracoronary injection in anesthetized dogs. A large number of the 2-(alpha-alkoxyimino)benzylpyridines strongly inhibited TEA and BaCl2-induced contraction, had no effect on 80 nM KCl-induced contraction, and increased the CBF to more than 200% of the basal flow at 10-30 micrograms/dog. In particular, (Z)-2-[5-bromo-alpha-(tert-butoxyimino)-4-fluoro-2-hydroxybenzyl]- 3- hydroxypyridine 1-oxide (7d) showed highly potent vasorelaxant activity (EC50 = 0.28 microM) comparable to that of levcromakalim (EC50 = 0.17 microM), and gave a significantly longer-lasting increase (T1/2 = 30 min) in the CBF compared to levcromakalim, nicorandil, nitroglycerin, or diltiazem (T1/2 = 5.2, 0.9, 0.4, and 2.2 min, respectively). It also exhibited a stable and long-lasting hypotensive effect (over 7 h) upon oral administration of 1 mg/kg in spontaneously hypertensive rats (SHRs).

Consideration of possible structural similarities between thromboxane A2 and the hydroquinone form of (R)-(+)-7-(3,5,6-trimethyl-1,4-benzoquinon-2-yl)-7- phenylheptanoic acid (R-(+)-AA-2414) led to the development of a new series of thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptor antagonists, namely 7-(4-fluorophenyl)-7-(2-hydroxyphenyl)heptanoic acids (I). These compounds were found to be potent TXA2/PGH2 receptor antagonists. Compounds having either a carbonyl or a hydroxymethyl group at the para-position of the phenolic hydroxy group exhibited most potent activities in this series. Compounds 14, 15, 18, and 26 inhibited the specific binding of [3H]U-46619 to guinea pig platelet membranes (IC50 = 4.4, 80, 32, and 13 nM, respectively), and also inhibited U-46619-induced human platelet aggregation (IC50 = 310, 69, 79, and 78 nM, respectively). Comparison of the UV spectra of the compounds with a carbonyl group at the para-position of phenolic hydroxy group revealed that the activity tended to increase in accordance with a decrease in the torsional angle between the carbonyl group and the phenol ring. These results suggested that the spacial location of the carbonyl and hydroxymethyl oxygen are important for significant increase in activity and that the carbonyl and hydroxymethyl oxygen at the para-position of the phenolic hydroxy group might interact with one of the TXA2/PGH2 receptor sites.

ortho-Substituted phenol derivatives with high optical purity have been obtained directly by Mitsunobu reaction between an appropriate phenol and an optically active benzyl alcohol. In this reaction, the chemical yield was well balanced with the optical purity of the ortho-substituted compound when 5 equiv. of phenol was allowed to react with 1 equiv. of alcohol in a solvent such as dichloroethane or toluene. In addition, it was confirmed by an X-ray analysis of the product that stereochemical inversion of the asymmetric centre took place in this reaction, as well as the usual Mitsunobu reaction. This reaction is useful in the preparation of optically active phenol derivatives possessing a diarylmethane moiety.

New cephalosporins modified in the acyl part of 7-(3'-oxobutyrylamino)cephalosporins (1), which have been described in the preceding paper, were synthesized by thiolation at the 2'- or the 4'-position, or by transforming the 3'-oxo group into a 3'-imino group. The most active compound in vitro was 3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-7-(4-methylthio-3-oxobutyrylamino)ceph-3-em-4-carboxylic acid (7c), which showed superior in vitro activity against Gram-positive and Gram-negative bacteria compared to the parent cephalosporin (1b) with the same 3-substituent. The ED50 value for 7c, however, was essentially equal to that of 1b in mice infected with Escherichia coli O-111.

A new series of omega-phenyl-omega-quinonylalkanoic acids and related compounds was synthesized. The compounds were tested for their inhibitory effects on U-44069-induced contraction of the rabbit aorta. (+/- )-7-(3,5,6-Trimethyl-1,4-benzoquinon-2-yl)-7-phenylheptanoic acid (4d) (AA-2414) with pA2 value of 8.28 was one of the most potent compounds. Compound 4d inhibited U-46619-induced contraction of the guinea pig lung (pA2 = 8.29) and U-44069-induced aggregation of the guinea pig platelet (IC50 = 3.5 x 10(-7) M). Compound 4d displaced the binding of [3H]U-46619 to guinea pig platelets (IC50 = 7.4 x 10(-9) M). Compound 4d also showed very potent inhibitory effects with an MED of 0.3 mg/kg (po) on U-46619-, LTD4-, PAF-, or IgG1-induced bronchoconstriction in guinea pigs. The enantiomers of 4d were prepared. The R-(+) isomer 8a was active in both in vitro and in vivo tests, but the S-(-) isomer 8b was much less active. We concluded that the antiasthmatic effects of 4d were based mainly on the TXA2 receptor antagonistic action. In addition, compound 4d showed potent inhibitory effects on PGD2-, PGF2 alpha-, and 11-epi-PGF2 alpha-induced contraction of the guinea pig tracheal strips. The diverse inhibitory effects might be expressed in terms of eicosanoid-antagonistic activity.

The anti-asthmatic activity of AA-2414 [(±)-7-(3,5,6-trimethyl-1,4-benzoquinon-2-yl-7-phenylheptanoic acid)] has been studied in vivo and in vitro . Experimental allergic asthma was inhibited by orally administered AA-2414 in a dose-dependent manner. AA-2414, 0.08∼1.25 mg/kg (p.o.), inhibited the bronchoconstriction in guinea pigs induced by a prostaglandin endoperoxide analogue (U-46619), leukotriene D 4 (LTD 4 ), and platelet activitating factor (PAF) with a long duration of action. The compound did not inhibit histamine-induced bronchoconstriction. AA-2414 reduced the induction of pulmonary inflation caused by LTD 4 aerosol inhalation. AA-2414 competitively inhibited the contractile response to U-46619 in guinea pig tracheal and parenchymal strips and dog saphenous vein strips with pA2 values of 7.69, 8.29 and 6.79, respectively. Furthermore, the contractile responses of guinea pig tracheal strip to PGD 2 , 9 a , 11s-PGF 2 and PGF 2 a were inhibited with pA2 values of 7.20, 7.79 and 5.71, respectively. These results suggest that AA-2414, a quinone derivative, is a novel, potent and orally active antagonist of a variety of spasmogenic prostanoids.

New compounds 3-acetoacetoxymethyl-7β-acylaminoceph-3-em-4-carboxylic acids (4) were synthesized from deacetylcephalosporin C (3a), after N-protection of the amino-adipoyl group followed by acetoacetylation of the 3'-hydroxyl with diketene and acyl exchange at the 7-position. They underwent a facile nucleophilic displacement of the 3'-acetoacetoxy group with heterocyclic thiols to afford 7β-acylamino-3-heterocyclicthio-methylceph-3-em-4-carboxylic acids (6) including SCE-963 (6e) in good yields.

The synthesis and the in vitro and in vivo antimicrobial activities of a series of 7-[2-(2-aminothiazol-4-yl)acetamido]cephalosporins (1) having varied 3-substituents, such as methyl, hydroxymethyl, acetoxymethyl, pyridiniomethyl and heterocyclicthiomethyls, are described. The derivatives having five membered heterocyclicthiomethyls exhibited strong inhibitory activities against Gram-negative organisms including some strains of Escherichia coli and Proteus morganii which are insensitive to cefazolin and cephaloridine. Pronounced activities were noted with 7-[2-(2-aminothiazol-4-yl)-acetamido]-3-[[[1-(2-dimethylaminoethyl)-1H-tetrazol-5-yl]thio]methyl]ceph-3-em-4-carboxylic acid (1y; SCE-963).

New compounds 3-acetoacetoxymethyl-7β-acylaminoceph-3-em-4-carboxylic acids (4) were synthesized from deacetylcephalosporin C (3a), after N-protection of the amino-adipoyl group followed by acetoacetylation of the 3'-hydroxyl with diketene and acyl exchange at the 7-position. They underwent a facile nucleophilic displacement of the 3'-acetoacetoxy group with heterocyclic thiols to afford 7β-acylamino-3-heterocyclicthio-methylceph-3-em-4-carboxylic acids (6) including SCE-963 (6e) in good yields.

General synthetic routes to quinone acids (8), quinone amides (9), quinone alcohols (10), and quinone methylketones (11) with polyprenyl side chains, in which allylic alcohols (3) are employed as the key intermediates, are described. The Claisen rearrangements and the Carrot reactions of the allylic alcohols (3) with ethyl orthoacetate and diketen produced the ethyl esters (4) and the methylketones (5), respectively. Quinone products (8), (10), and (11) were recovered by oxidative demethylation of hydroquinone dimethyl ethers (4), (5), and (7) or by acid hydrolysis of hydroquinone bis(methoxymethyl) ethers (4) and (5) followed by ferric chloride oxidation. Amidation of quinone acids (8) led to the formation of quinone amides (9). Inhibitory effects of these quinone derivatives on the generation of the slow reacting substance of anaphylaxis (SRS-A) in the lungs of sensitised guinea pigs are evaluated.

A new series of quinone derivatives with alkenyl and alkynyl groups in the side chain has been synthesised. A ready and novel synthetic method for the preparation of quinone derivatives via application of a 4-hydroxybutylation reaction discovered in our laboratory has been developed. Oxidative demethylation of the hydroquinone dimethyl ethers (5), (9), and (10) with cerium (IV) ammonium nitrate selectively leads to the formation of the desired quinone derivatives (11)–(13) in good yield, in spite of the presence of double or triple bonds, hydroxy groups in the side chains, and/or four methoxy groups on the same phenyl ring. Inhibitory effects of these quinone derivatives on the formation of leukotrienes [LTC4, LTD4, LTB4, and (5S,12S)- and (5S,12R)-6-trans-LTB4] and 5-hydroxyicosa-6,8,11,14-tetraenoic acid (5-HETE) in rat basophilic leukaemia (RBL-1) cells were evaluated. It was found that quinone derivatives such as 2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-1,4-benzoquinone (AA-861)(12d) proved to be potent and specific inhibitors of leukotrienes and 5-HETE formation from arachidonic acid.