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Three-dimensional models for the catalytic domain of gelatinases (MMP-9 and -2) have been constructed based on the X-ray crystal structure of MMP-3. Conformations of the loop segment which forms the bottom half of the S1' subsite but shows conformational diversity among the crystal structures of other MMPs have been explored by simulated annealing of each gelatinase model complexed with two highly potent "probe" inhibitors. Representative catalytic domain models have been selected for each gelatinase from the set of generated conformations based on shape complementarity of the loop to the probe inhibitors. The single model selected for MMP-9 was utilized to explain the structure-activity relationship of our novel sulfonamide inhibitors. Molecular dynamics (MD) simulations of the complex models revealed important features of the binding mechanism of our inhibitors: (i) the ligand carboxylate group coordinating to the catalytic zinc ion and hydrogen bonding to the Glu219 side chain, (ii) one of the sulfonyl oxygens forming hydrogen bonds with the main chain NHs (Leu181 and Ala182), (iii) the sulfonyl substituent making extensive hydrophobic contact with the S1' subsite. The gauche conformation exclusively adopted by the sulfonamide C-N-S-C torsion plays an important role in achieving the third binding feature by properly directing the substituent into the S1' subsite. Improvement of the inhibitory activity according to straight elongation of the sulfonyl substituent was attributed to an increase of the hydrophobic contact between the substituent and the S1' subsite. Structural modifications which alter the straight shape of the substituent lead to deterioration of the activity. On the other hand, the two candidate models selected for MMP-2 differ in the bottom shape of the S1' subsite: one with a channel-like subsite and the other with a pocket-like subsite resembling that of the MMP-9 model. The bottom shape was experimentally probed by chemical synthesis of inhibitors having elongated sulfonyl substituents whose terminal alkyl groups were shown by MD simulations to protrude from the S1' subsite bottom into the solvent. Gelatinase assays of these inhibitors showed that elongation of the substituent significantly reduces activity against MMP-9 while retaining activity against MMP-2, consequently increasing the selectivity between MMP-2 and -9. The results confirm that MMP-9 has a pocket-like S1' subsite with a floorboard and MMP-2 has a channel-like S1' subsite.

We achieved a total synthesis of terprenin, a novel potent immunoglobulin E antibody suppressant which was obtained from the fermentation broth of Aspergillus candidus RF-5672 and has a highly oxygenated p-terphenyl skeleton with a prenyloxy side chain. The key steps relied on the Suzuki reaction to construct the terphenyl skeleton and on regioselective halogenations to selectively combine the aromatic rings. The highly efficient and practical production of this important natural product offers promise for the development of a new type of antiallergic drug.

The substrate 1 of cytosolic phospholipase A2 (cPLA2) is an ether-type thiophospholipid with arachidonic acid at the C-2 position and is required for the chromogenic assay for reliable and convenie...

An ongoing search for new antifolate drugs useful against rheumatoid arthritis (RA) led us to prepare new methotrexate (MTX) derivatives containing enantiomerically pure L-erythro- or L-threo-gamma-fluoroglutamic acid. The derivatives in which the phenyl ring was replaced by a 3'-substituted phenyl or methylthiophene ring showed potent immunosuppressive activities, including in vitro inhibition of mitogen responses to both T and B cells and in vivo inhibition of antibody production in mice. These compounds also exhibited inhibitory activity in adjuvant arthritis in rats. Their toxicity was lower than that of MTX, which was probably due to the strong electronegativity of fluorine, which increases the acidity of the gamma-carboxyl group and thereby decreases polyglutamylation in normal cells. These results revealed the potential of the fluorinated MTX derivatives as candidate drugs for the treatment of RA.

Abstract: Ras-oncogene is now thought to be one of the most important oncogenes which is evidenced in the correlation with human cancers. Point mutation in ras-gene correlates with transformation caused by ras and is found in human cancers with high frequency, such as 90% in pancreatic cancer, 50% in colon cancer and 30% in lung cancer. Ras (product of ms-oncogene) has GTPase activity and loses its activity with point mutation, leading to transformation. Active GTP-binding form of Ras is a key molecule of signal transduction in cell growth, differentiation and transformation. Inhibitors of ms-transformation will be good candidates of anti-cancer agents. Although many inhibitors of ras­ transformation have been reported up to now including macromolecules (genes, nucleotides, antibodies), we summarize the small-molecule compounds, which inhibit ms-transformation in direct or indirect manner in this review. Direct inhibitors of ras include inhibitors of farnesylation of Ras. Farnesyltransferase inhibitors (L- 744,832, etc) include peptidomimetics with the rational drug design for C-terminus of Ras and natural products. Inhibitors of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase (Lovastatin, etc) which block cholesterol metabolism, inhibit farnesylation of Ras by decreasing the amount of the substrate of farnesyltransferase (Frase). Indirect inhibitors of ras with known mechanisms include the inhibitor of inositol monophosphate (IMP) dehydrogenase (oxanosine), the inhibitor of mitogen-activated protein kinase kinase (MAPK kinase)(PD98059), the inhibitor of MAPK (apigenin), the inhibitors of protein kinase C (PKC) (UCN- 01, etc), the inhibitors of phosphatidylinositol 3-kinase (Pl3K) (Wortmannin and L-294002), the inducer of the transcription factor JunD (oxamflatin) and the inhibitors of histone deacetylase [trichostatin A (TSA) and trapoxins]. Almost all compounds are now under development, and will be evaluated in clinical studies as anticancer agents.

Enantiomerically pure L- erythro - and L- threo -4-fluoroglutamic acids 1a and 1b were conveniently prepared. The key steps in this synthesis relied upon separation of diastereomers of N -chloroacetyl-4-fluoroglutamic acid 5-methyl ester 7 by recrystallization and enzymatic resolution of enantiomers of the resulting 7(a+c) and 7(b+d) by aminoacylase. Protection of the γ-carboxyl group as a methyl ester was found to be crucial for this enzymatic reaction.

5beta-Methoxy (20), 14-methyl (24), 14,14-dibromo-15-nor (25), 8-O-acyl (26-45), 8-O-alkyl (46), 8-O-alkoxycarbonyl (47, 48), and 8-O-carbamoyl (49) derivatives of PA-48153C, a novel immunosuppressant isolated from fermentation products of Streptomyces prunicolor PA-48153, were prepared. These compounds were found to retain the inhibitory activity on the responses of both T and B cells to mitogens. Among them, the C-8 hexanoate 28 showed potent suppressive effects on mitogen responses with less cytotoxicity to EL4 cells and was selected for in vivo evaluation.

Phospholipase A2 is an enzyme which hydrolyzes the sn-2 position of certain cellular phospholipids. The liberated lysophospholipid and arachidonic acid are precursors in the biosynthesis of various biologically active products. As human nonpancreatic sPLA2 is present in high levels in the blood of patients in several pathological conditions, the potent sPLA2 inhibitors have been suggested to be useful drugs. Here we describe the synthesis, structure-activity relationship, and inhibitory activities of indolizine and indene derivatives. 1-(Carbamoylmethyl)indolizine derivatives and 1-oxamoylindolizine derivatives exhibited very potent inhibitory activity. The former was unstable to air oxidation, but the latter exhibited an improvement both in stability and in potency. Some compounds approached the stoichiometric limit of the chromogenic assay.

Phospholipase A2 is an enzyme which hydrolyzes the sn-2 position of certain cellular phospholipids. The liberated lysophospholipid and arachidonic acid are precursors in the biosynthesis of various biologically active products. As human nonpancreatic sPLA2 is present in high levels in the blood of patients in several pathological conditions, the potent sPLA2 inhibitors have been suggested to be useful drugs. Here we describe the synthesis, structure-activity relationship, and inhibitory activities of indolizine and indene derivatives. 1-(Carbamoylmethyl)indolizine derivatives and 1-oxamoylindolizine derivatives exhibited very potent inhibitory activity. The former was unstable to air oxidation, but the latter exhibited an improvement both in stability and in potency. Some compounds approached the stoichiometric limit of the chromogenic assay.

An effective and practical enantioselective synthesis of half-esters of bicyclo [2.2.1] heptane-2,3-dicarboxylic acid was developed by enantioselective fission of σ-symmetrical cyclic anhydrides with chiral mandelic acid derivatives, followed by deprotection of the mandelate moiety, crystallization, and further modification. These half-esters are very attractive chiral building blocks for numerous natural products, and this new method makes possible their synthesis via common intermediates with high optical purity

The substrate 1 of cytosolic phospholipase A2 (cPLA2) is an ether-type thiophospholipid with arachidonic acid at the C-2 position and is required for the chromogenic assay for reliable and convenie...

An effective and practical enantioselective synthesis of half-esters of bicyclo [2.2.1] heptane-2,3-dicarboxylic acid was developed by enantioselective fission of σ-symmetrical cyclic anhydrides with chiral mandelic acid derivatives, followed by deprotection of the mandelate moiety, crystallization, and further modification. These half-esters are very attractive chiral building blocks for numerous natural products, and this new method makes possible their synthesis via common intermediates with high optical purity

An efficient and extremely practical enantioselective fission of pro-chiral bicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride was applied to the asymmetric synthesis of the potent and orally active thromboxane A 2 (TXA 2 ) receptor antagonist, S-1452

The synthesis of 16 metabolites of S-1452, an orally active thromboxane A2 (TXA2) receptor antagonist, is described. Regioselective hydroxylation at C-5 or C-6 of the bicyclo[2.2.1]heptane skeleton of the optically active intermediate 16 was attempted by using 9-borabicyclo[3.3.1]nonane followed by H2O2 or m-chloroperbenzoic acid (m-CPBA) and then LiA1H4, to obtain the hydroxylated product 17a or 17b, respectively. Modification of the C-2 substituent of 17a and 17b afforded eight metabolites of S-1452. Eight non-hydroxylated metabolites were synthesized by using a similar reaction sequence.

Three stereoisomers of S-145 (1) with variations at the side-chain junctions were synthesized. Endo-cis isomer 10 and N-exo-trans isomer 18 were obtained via the common intermediate 5 having an endo-fused ring structure. Exo-cis isomer 28 was prepared via exo-fused azetidino compound 21. Inhibitory concentrations (IC50) of the sodium salts newly obtained for platelet aggregation were measured using washed rat platelets (WP) and human platelet-rich plasma (PRP). The IC50 values of these compounds for contraction of the rat aorta were also measured. Compound 1 of N-endo-trans structure and N-exo-trans isomer 18 exhibited more potent inhibitory activity than cis-isomers 10 and 28 against responses induced by TXA2-related substances for rat WP and rat thoracic aorta. However, these compounds exhibited almost comparable inhibitory activity for human PRP.

Regioselective halogenations and Suzuki reactions ensure proper linkage of the aromatic rings in two total syntheses of terprenin (1). Both routes make it possible to prepare 1 efficiently and in large quantity.

Regioselektive Halogenierungen und Suzuki-Reaktionen ermoglichen die richtige Verknupfung der aromatischen Ringe in zwei Totalsynthesen von Terprenin 1. Durch beide Reaktionswege kann 1 effizient und in groserer Menge erhalten werden.

Novel prostaglandin D(2) (PGD(2)) receptor antagonists were synthesized as a potential new class of antiallergic agents having a bicyclo[2.2.1]heptane ring system with sulfonamide groups. Some of them exhibit extremely potent antagonism of the PGD(2) receptor in radioligand binding and cAMP formation assays with IC(50) values below 50 nM and much less antagonism of TXA(2) and PGI(2) receptors. These potent PGD(2) receptor antagonists, when given orally, dramatically suppress various allergic inflammatory responses such as increased vascular permeability in allergic rhinitis, conjunctivitis, and asthma models. The excellent pharmacological profiles of PGD(2) receptor antagonists, originally synthesized in our laboratories, are of potentially great clinical significance. This study also provides experimental evidence suggesting that PGD(2) plays an important role in the pathogenesis of allergic diseases.

In an earlier paper, we reported that novel prostaglandin D(2) (PGD(2)) receptor antagonists having the bicyclo[2.2.1]heptane ring system as a prostaglandin skeleton were a potent new class of antiallergic agents and suppressed various allergic inflammatory responses such as those observed in conjunctivitis and asthma models. In the present study, we synthesized PGD(2) receptor antagonists having the 6,6-dimethylbicyclo[3.1.1]heptane ring system. These derivatives have the amide moiety, in contrast to those with the bicyclo[2.2.1]heptane ring system, which have the sulfonamide group. The derivatives having the 6,6-dimethylbicyclo[3.1.1]heptane ring also exhibited strong activity in PGD(2) receptor binding and cAMP formation assays. In in vivo assays such as allergic rhinitis, conjunctivitis, and asthma models, these series of derivatives showed excellent pharmacological profiles. In particular, compound 45 also effectively suppressed eosinophil infiltration in allergic rhinitis and asthma models. This compound (45, S-5751) is now being developed as a promising alternative antiallergic drug candidate.

Our continuing program to develop new antifolate drugs useful against rheumatoid arthritis led us to modify the pteridine ring of gamma-fluoromethotrexate. Pyrrolopyrimidine derivatives 1e and 1t were found to exhibit potent suppressive effects on the responses of both T and B cells to mitogens, although tetrahydropyridopyrimidine derivatives 2e and 2t and quinazoline derivatives 3e, 3t and 4e showed very weak suppressive activities. Thus, conversion of the pteridine ring of gamma-fluoromethotrexate to a pyrrolopyrimidine ring led to a new potential antirheumatic compound.

Various N-sulfonylamino acid derivatives were synthesized and evaluated for their in vitro and in vivo activities to inhibit type IV collagenase (MMP-9 and MMP-2). When the amino acid residue and the sulfonamide moiety were modified, their inhibitory activities were greatly affected by the structure of the sulfonamide moiety. A series of aryl sulfonamide derivatives containing biaryl, tetrazole, amide, and triple bond were found to be potent and highly selective inhibitors of MMP-9 and MMP-2. In addition, these compounds were orally active in animal models of tumor growth and metastasis. These results revealed the potential of the N-sulfonylamino acid derivatives as a new type of candidate drug for the treatment of cancer.

We prepared several types of derivatives of thielocin B3, a very potent naturally occurring inhibitor for human nonpancreatic secretory PLA 2 (sPLA 2 -II), and conducted a structure-activity relationship study to identify potent sPLA 2 -II inhibitors with the aim of developing antiinflammatory drugs. The total number of aromatic rings is critical for sPLA 2 -II inhibition, and the best result was obtained in the case of six rings. The structure of the central part of the inhibitors was not specific, and potent inhibitors were found among the sulfide, sulfone, ether, methylene, and amino derivatives. Although a diester of the terminal carboxylic acid lost its inhibitory activity, having both of the carboxylic acids was not necessary for expression of activity, as illustrated by a glycine derivative with the benzyl ester group 36. Among the newly synthesized derivatives, 18, 20, 29, and 36 showed very potent human sPLA 2 -II inhibitory activity comparable to that of natural thielocin B3. Their IC 50 values are in the range 0.069-0.14 μM, and they are a class of compounds showing the most potent sPLA 2 -II inhibition to date.

S-145, (+/-)-(5Z)-7-[3-endo-[(phenylsulfonyl)amino]bicyclo[2.2.1] heptenoic acid, its chain analogues HO2C(CH2)nNHSO2Ph (n = 3-8, 10, and 11) 1-8, and (5Z)-9-(phenylsulfonyl) aminonon-5-enoic acid (9) were synthesized in order to elucidate the dependence of the conformation in solution and of the pharmacological activity on the side-chain length. Their FTIR spectra were measured in dilute CCl4 solution. For these compounds, intramolecular hydrogen bonds similar to those observed for S-145 were found between the carboxyl and sulfonamido groups. A linear relationship was also found between the percentage (rho) of the intramolecular hydrogen-bonded molecules and the n value. Compounds 1-9 were examined in vitro for inhibitory concentrations (IC50) against U-46619- and collagen-induced aggregations for rabbit and rat washed platelets (WP), respectively, and U-46619-induced contraction for rat aorta. Three kinds of TXA2 receptor antagonistic potencies [log(1/IC50)] showed parabolic correlations with the n value, though the rho value was in direct proportion to the n value. The log (1/IC50) values for 6 (n = 8), which forms a 12-membered ring similar to the one observed for S-145, were found to be maximal values in 1-8 and were comparable to those for BM-13177. In compounds 9 (rho = 83%) and S-145 (rho = 89%), the IC50 values of 41 and 2.9 nM for rat WP were 10 and 141 times lower than that of 6 (rho = 52%), respectively. In these compounds, which form the 12-membered ring, the inhibitory potencies increase as the rho value increases.

A broadly applicable method has been demonstrated for the efficient synthesis of chiral bicyclic guanidines such as 1 from chiral α-amino acids.

A broadly applicable method has been demonstrated for the efficient synthesis of chiral bicyclic guanidines such as 1 from chiral α-amino acids.

A synthesis of several carbapenem antibiotics including 9-methoxythienamycin is described. The final deprotection of C-3 esters was accomplished by a novel procedure using aluminum trichloride under a very mild condition. The antibacterial activity against Gram-positive and Gram-negative bacteria is shown.

A number of new optically active 1-oxacephem compounds were synthesized and tested for antibacterial activity. Various 7 alpha-unsubstituted 1-oxacephem nuclei 2a approximately 3 and a 7 alpha-methoxy-1-oxacephem nucleus 3, reported previously, were converted into the corresponding phenylacetylamino-, 2-thienylacetylamino-, D-mandelylamino-, D-phenylglycylamino-, and arylmalonylamino-1-oxacephem carboxylic acids. All the compounds except for the phenylglycylamine derivatives exhibited four-to sixteen-fold enhanced antibacterial activity compared with that of the corresponding cephalosporins. A combination of the 7 alpha-methoxy-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-1-oxacephem nucleus and a 7 beta-arylmalonylamino side chain, as represented by compound 1 (disodium salt of 33), produced the highest efficacy among them: high antibacterial activity with a widely expanded spectrum against Gram-negative bacteria including resistant strains and Pseudomonas aeruginosa was observed.

Relationships between intrinsic antibacterial activity and beta-lactam reactivity of 7 beta-[(4-hydroxyphenyl)acetyl]amino- and 7 beta-[(4-hydroxyphenyl)malonyl]amino derivatives of 1-oxa- and 1-thiacephems, with or without the 7 alpha-methoxy group (1-8), were investigated in order to clarify the enhanced antibacterial activity of latamoxef disodium (1). Substituent effects of a carbon atom at the 1- and 7 alpha-positions were also investigated by using racemic 1-carbacephem 9 and 7 alpha-methyl-1-oxacephem 10. Syntheses of 2-8 and 10 are also described. Acid chlorides derived from the O-benzyloxycarbonyl derivative of (4-hydroxyphenyl)acetic acid and the p-methoxybenzyl derivative of (4-hydroxyphenyl)malonic acid smoothly effected the introduction of these side chains. Conjugate addition of lithium dimethylcuprate to the quinoid system in 16 proceeded stereospecifically, furnishing the 7 alpha-methyl group for the synthesis of 10. Values of log (1/C) averaged for the sensitive Gram-negative strains (Escherichia coli NIHJ JC-2 and Klebsiella pneumoniae SRL-1) were taken as an estimation of the intrinsic antibacterial activity. The chemical reactivity of the beta-lactam ring was estimated either by pseudo-first-order rate constants (k) of alkaline hydrolysis measured at pH 9.20 and 35.0 degrees C or by infrared stretching frequencies of the beta-lactam carbonyl measured in dimethyl sulfoxide. Substitution of an oxygen atom at the 1-position increases both the hydrolysis rates and the antibacterial activity by a factor of approximately 6.3, while substitution of a 7 alpha-methoxy group increases the antibacterial activity by a factor of approximately 3.2 without significant change in the hydrolysis rates. The effect of the 7 alpha-methoxy group on the transition state in alkaline hydrolysis is discussed. Substitutions at the 1-position with a methylene group and, especially, at the 7 alpha-position with a methyl group greatly diminished the antibacterial activity, whereas the hydrolysis rate remained high with the substitution of a methylene group. Substitution of an oxygen atom for the sulfur atom at the 1-position of 1-thiacephems increased the beta-lactam carbonyl frequencies by approximately 6 cm-1, whereas introduction of a 7 alpha-methoxy group in 1-thia- and 1-oxacephems reduced the frequencies by approximately 5 cm-1.

F.t.i.r. spectra of the thromboxane A2 receptor (TXA2R) antagonists, S-145 (1) and BM-13177 (4) and TXA2R agonist, U-46619 (6), have been measured in dilute CCl4 and CHCl3 solutions. These spectra were subjected to curve analysis to separate overlapping absorption bands. For compounds (1) and (6), the intramolecular hydrogen bonds involving twelve- and fifteen-membered rings were found between the functional groups of α- and ω-side chains, respectively. The formation ratio (p) of the intramolecular hydrogen bond in CCl4 showed the high values of 89% for (1) and 81% for (6). For (4), the intramolecular hydrogen bond was found between the NH bond in the 2-sulphonamido group and π-electrons on the 1-phenyl group. In order to estimate ρ values of (1) and (6), the concentration dependence of the F.t.i.r. spectra of lauric acid (7) as the model compound of the α-side chain was also measured in CCl4 and CHCl3 solutions. The true molar absorption coefficients of OH and CO stretching bands and an association constant for (7) were determined. On the basis of information on intramolecular hydrogen bonding, the conformations of (1), (4), and (6) were examined and found to resemble each other.