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At least 109 records · Page 6Linked to original sources
PubMed2004

Regional hemodynamic effects of the N-(2-benzoylphenyl)-L-tyrosine peroxisome proliferator-activated receptor-gamma ligand, GI 262570 [(S)-2-(2-benzoylphenylamino)-3-[4-[2-(5-methyl-2-phenyl-2-oxazol-4-yl)ethoxy]phenyl]propionic acid], in conscious rats.

This study provides novel data on the regional hemodynamic effects of the peroxisome proliferator-activated receptor-gamma activator, GI 262570 [(S)-2-(2-benzoylphenylamino)-3-[4-[2-(5-methyl-2-phenyl-2-oxazol-4-yl)ethoxy]phenyl]propionic acid], in conscious, male Sprague-Dawley rats. Administration of GI 262570 twice daily for 4 days caused a slowly developing, modest fall in mean arterial blood pressure, associated with a progressive, hyperemic hindquarters vasodilatation, but with no consistent changes in renal or mesenteric hemodynamics. The hindquarters vasodilator effect of GI 262570 was not inhibited by the beta2-adrenoceptor antagonist, ICI 118551 ((+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl) amino]-2-butanol hydrochloride), and was still apparent in the presence of the alpha-adrenoceptor antagonist, phentolamine. Neither the latter, nor antagonism of angiotensin (AT1) and endothelin (ETA and ETB) receptors unmasked vasodilator responses to GI 262570 in the renal or mesenteric vascular beds. In the presence of GI 262570, vasodilator responses to acetylcholine and vasoconstrictor responses to methoxamine were normal. Furthermore, the cardiovascular responses to nonselective nitric-oxide synthase inhibition were not influenced by GI 262570. Collectively, these results indicate that the vasodilator action of GI 262570 is specific to the hindquarters vascular bed (of those studied), does not involve alpha- or beta2-adrenoceptors, and is not associated with a change in basal or stimulated nitric oxide release.

Acetylcholine↗
PubMed1996

From peptide precursors to oxazole and thiazole-containing peptide antibiotics: microcin B17 synthase.

Esherichia coli microcin B17 is a posttranslationally modified peptide that inhibits bacterial DNA gyrase. It contains four oxazole and four thiazole rings and is representative of a broad class of pharmaceutically important natural products with five-membered heterocycles derived from peptide precursors. An in vitro assay was developed to detect heterocycle formation, and an enzyme complex, microcin B17 synthase, was purified and found to contain three proteins, McbB, McbC, and McbD, that convert 14 residues into the eight mono- and bisheterocyclic moieties in vitro that confer antibiotic activity on mature microcin B17. These enzymatic reactions alter the peptide backbone connectivity. The propeptide region of premicrocin is the major recognition determinant for binding and downstream heterocycle formation by microcin B17 synthase. A general pathway for the enzymatic biosynthesis of these heterocycles is formulated.

Adenosine Triphosphate↗
PubMed2006

Expeditious syntheses of conjugated allenyl esters and oxazoles through a cascade reaction of alpha-alkynyl malonates under alkaline conditions.

Diethyl alpha-alkynyl-alpha-methoxymalonates (2a--e) were smoothly hydrolyzed and then decarboxylated under alkaline conditions employing 1 N KOH in EtOH to give conjugated allenyl esters (6a--e) in high yields, and similar alkaline treatment of diethyl alpha-alkynyl-alpha-acetylaminomalonates (5a, b, d, e) furnished unexpectedly the oxazoles (7a, b, d, e) having three substituent groups in excellent yields.

Alkalies↗
PubMed1982

2-Ethyl-5-(3-indolyl)oxazole from Streptomyces cinnamomeus discovered by chemical screening. Characterization and structure elucidation by X-ray analysis.

In the lipophilic extracts from Streptomyces cinnamomeus 2-ethyl-5-(3-indolyl)oxazole (1a) was detected by chemical screening methods. The structure of the crystalline 1a was determined by spectroscopic and X-ray analysis. The new mono- and dibromo derivatives 1b and 1c are described. 1a is identical with pimprinethine and belongs to a group of microbial indole alkaloids, which can be regarded as masked tryptamine derivatives.

Chemical Phenomena↗
PubMed1995

The chemistry of pseudomonic acid. Part 14. Synthesis and in vivo biological activity of heterocyclyl substituted oxazole derivatives.

Semisynthetic analogues of pseudomonic acid A have been prepared containing a heterocyclyl substituted oxazole. Derivatives in which the heterocycle was thiophene, furan, pyridine, or isoxazole showed good antibacterial potency and were further evaluated in vivo. Both pharmacokinetic parameters and oral activity against an experimental intraperitoneal sepsis were superior to results obtained from previously described pseudomonic acid A derivatives.

Animals↗
PubMed1976

Derivatives of 2H,3H-benzimidazo(1,2-b)oxazole.

The Authors report the synthesis and chemical properties of a number of derivatives of 2H,3H-benzimidazo(1,2-b)oxazole. These substances were prepared in order to investigate their pharmacological activity.

Benzimidazoles↗
PubMed1992

[2-Amino-oxazoles as potential H-bonding agents in virostatic research. 4. Pharmacokinetics and pharmacologic-toxicologic profile of 2-guanidino-4,5-dipropyloxazole hydrochloride].

Out of the group of 2-amino-oxazoles 1 was found to be the most potent antiviral compound. Following p.o. or s.c. administration to rats, the 14C-labeled 1 was quickly and completely absorbed. The TRA was eliminated mainly via the kidneys and the liver with half-lives between 32 and 42 h. The acute pharmacodynamic effects of 1 were decrease of blood pressure, bradycardia, and inhibition of both gastric emptying and acid secretion. On smooth muscles spasmolytic and alpha-anti-adrenergic actions were predominant. After single administration the following MTD's were determined: 30 (mouse), 20 (rat), 10 mg/kg i.v. (pig), and 500 (mouse, rat), greater than 100 mg/kg p.o. (pig), respectively. In a subchronic toxicity study in rats, oral doses of 1 between 15 and 240 mg/kg given daily for 4 weeks were tolerated without any severe alterations related to the drug.

Administration, Oral↗
PubMedDate not supplied

Pyrazolo[3,4-d][1,2,3]triazole-1-carboxamides and 5-alkylaminopyrazolo[3,4-d]oxazoles: synthesis and evaluation of the in vitro antifungal activity.

A series of N-alkyl-N'-(4-diazo-5-pyrazolyl)-ureas (4) was thermally and photochemically converted into pyrazolo [3,4-d][1,2,3]triazole derivatives (5,6) and 5-alkylaminopyrazolo[3,4-d]oxazoles (7) respectively. The products were tested for in vitro antifungal activity against Fusarium culmorum, Botrytis cinerea, Phoma betae, Pythium ultimum, Sclerotinia minor and Rhizoctonia solani. The MIC and ED50 values of compound (6) against some of the test fungi were comparable to those of the reference fungicides iprodione and mancozeb.

Aminoimidazole Carboxamide↗
PubMed1991

Studies on the antibacterial action of novel gem-diphenyl-spiro-cyclopropano- oxazolones and 2-aryl(alkyl)-4-ylidene-oxazol-5-ones.

The preparation and in vitro antibacterial activity of a novel series of gem-diphenyl-spiro-cyclopropano-oxazolones (cis-1,2,2,5-tetraphenyl 6-oxa-4-azaspiro[2.4]hept-4-en-7-one) are described. The overall activity of these compounds was higher than that of the 2-aryl(alkyl)4-ylidene-oxazol-5-ones (azlactones). The gem-diphenyl-spiro-cyclopropano-oxazolones 1-4 have emerged as the most potent derivatives when tested against bacteria.

Anti-Bacterial Agents↗
PubMedDate not supplied

Metabolism of ethyl 2-(4-chlorophenyl)-5-(2-furyl)-oxazole-4-acetate, a new hypolipidemic agent, in the rat, rabbit, and dog. Glucuronidation of carboxyl group and cleavage of furan ring.

Metabolism of ethyl 2-(4-chlorophenyl)-5-(2-furyl)-oxazole-4-acetate (TA-1801), a new hypolipidemic agent, was studied in the rat, rabbit, and dog. Animals were given a single oral dose of 50 mg/kg TA-1801 labeled with 14C. The first metabolic reaction for TA-1801 was hydrolysis of the ester linkage. The resulting metabolite M1 was found to undergo further biotransformations, i.e. glucuronidation at the carboxyl group and ring cleavage of the furan group. These metabolic pathways were observed in all the species examined, although species differences were seen in the amount of metabolites.

Animals↗
PubMed1984

Effects of ethyl-2-(4-chlorophenyl)-5-ethoxy-4-oxazole acetate (Y-9738) on the serum lipids of patients with hyperlipidemia and/or hypo-HDL-emia.

With the view of examining the serum lipid metabolism-improving action of a new compound, ethyl-2-(4-chlorophenyl)-5-ethoxy-4-oxazole acetate (Y-9738), 900 mg was administered to 47 patients with various diseases associated with hyperlipidemia and/or hypo-HDL (high density lipoprotein)-emia for successive 16 weeks. Serum HDL-cholesterol increased significantly 4 weeks after the administration (mean 11.8%, p less than 0.01). In the patients with hypo-HDL-emia who showed the initial level of 50 mg/dl or less, the degree of increase was more remarkable (mean 16,4%, p less than 0.01), and a significant increase was noted until 12 weeks later. Further, a similar change was noted in respect to serum HDL-phospholipid. The main apoprotein of HDL, apoprotein A (I + II) began to increase significantly 4 weeks after the institution of the administration. At the end of the trial, it increased by mean 31% (p less than 0.01). Y-9738 did not exert any significant effect on serum total cholesterol, triglyceride and phospholipid, but it caused a reduction in so-called atherogenic indexes.

Adult↗
PubMed1994

Non-prostanoid prostacyclin mimetics. 6. Derivatives of 2-[3-[2-(4,5-Diphenyl-2-oxazolyl)ethyl]phenoxy]acetic acid modified beta-to the oxazole ring.

2-[3-[2-(4,5-Diphenyl-2-oxazolyl)ethyl]phenoxy]acetic acid, 1, has been described as a non-prostanoid PGI2 mimetic that demonstrates anti-thrombotic properties of long duration in animal models of thrombosis. The effects of substitution and modification of the carbon beta-to the oxazole heterocycle of 1 were examined and equated with the potency of the compounds as inhibitors of ADP-induced human platelet aggregation in vitro. Potency was sensitive to both the size of the substituent and the identity of the beta-atom. The carbamates 13c-e demonstrated IC50's of 0.28-0.36 microM and were significantly more potent than the progenitor 1, IC50 = 1.2 microM. The ethyl carbamate 13c displaced [3H]-iloprost from platelet membranes in a concentration-dependent fashion that was half maximal at 20 nM, which compares with IC50's of 171 nM for 1 and 39 nM or unlabelled iloprost. Carbamate 13c stimulated platelet adenylate cyclase but the maximal effect was less than that observed for PGI2, identifying 13c as a partial agonist at the platelet PGI2 receptor.

Cell Membrane↗
PubMedDate not supplied

First 3-D structure determination of a peptide oxazol-5(4H)-one with a chiral protein amino acid in the heterocyclic moiety: an x-ray diffraction analysis of the enantiomeric and racemic Goodman oxazolone.

The x-ray diffraction structure analyses of the L-enantiomeric and racemic forms of the 2-(1'-benzyloxycarbonylamino-1'-methyl) ethyl-4-benzyl-oxazol-5(4H)-one, the Goodman oxazolone, have been performed. In the crystal state the oxazolone ring of the enantiomeric compound is nearly sandwiched between the two phenyl rings, whereas in the racemate the phenyl ring of the N alpha-protecting group moves away from the oxazolone ring.

Crystallography, X-Ray↗
PubMed1998

Oxazole yellow dye interactions with short DNA oligomers of homogeneous base composition and their hybrids.

Interactions between short single-stranded DNA oligomers of homogeneous base composition and the fluorescent probes oxazole yellow (YO) and its homodimer YOYO are described. The oligomers included 15-mers and 30-mers of polydA, polydT, polydG, and polydC. Interactions between the dyes and DNA hybrids formed from complementary homogeneous strands of equal length were also investigated. No interactions were observed between the dyes and the monomeric monophosphate nucleosides A, G, T, or C. The dyes were found to interact much more strongly with the purine oligomers polydA and polydG than with the pyrimidine oligomers polydT and polydC. PolydA of both lengths has strong interactions with YOYO, whereas the polydG 30-mer interacts strongly with monomeric YO. The 15-mers of polydG and polydC of both lengths show little interaction with either dye. Interactions of the dyes with the polydA/polydT and polydG/polydC hybrids tend to be dominated by interactions with polydA and polydG, respectively. Although dye interactions generally were facilitated by hybridization, particularly for polydA/polydT, the interactions were similar to those with the single strands and different from those that have been observed in long double-stranded DNA.

Base Composition↗
PubMed2002

DNA melting in the presence of fluorescent intercalating oxazole yellow dyes measured with a gel-based assay.

We measured the effect of the intercalating oxazole yellow DNA dye quinolinium,4-[(3-methyl-2(3H)-benzoxazolylidene)methyl]-1-[3-(trimethylammonio)propyl]-,diiodide (YO-PRO) and its homodimer (YOYO) on the melting of self-complementary DNA duplexes using a gel-based assay. The assay, which requires a self-complementary DNA sequence, is independent of the optical properties of the molecules in solution. The melting temperature of the DNA is observed to increase in direct proportion to the number of occupied intercalation sites on the DNA, irrespective of whether the dye molecules are in monomer or dimer form. The increase is approximately 2.5 degrees C for each intercalation site occupied in the presence of 38 mM [Na(+)], for dye/duplex ratios in which less than 1/5 of the available intercalation sites are occupied.

Benzoxazoles↗
PubMed2004

Anthranilate 4H-oxazol-5-ones: novel small molecule antibacterial acyl carrier protein synthase (AcpS) inhibitors.

D-optimal design and Projection to Latent Structures (PLS) analysis were used to optimize screening hit 5 (B. subtilis AcpS IC(50): 15 microM, B. subtilis MIC: >200 microM) into a series of 4H-oxazol-5-one, small molecule, antibacterial, AcpS inhibitors. Specifically, 15, 16 and 18 show microM or sub-microM AcpS inhibition (IC(50)s: 15: 1.1 microM, 16: 1.5 microM, 18: 0.27 microM) and moderate antibacterial activity (MICs: 12.5-50 microM) against B. subtilis, E. faecalis ATCC, E. faecalis VRE and S. pneumo+.

Anti-Bacterial Agents↗
PubMedDate not supplied

Synthesis, photophysical effects, and DNA targeting properties of oxazole yellow-peptide bioconjugates.

The design of a dsDNA-sensitive fluorescent bioconjugate capable of targeting a specific DNA sequence with high efficiency is described. The bioconjugate has the molecular recognition features of the polypeptide from a DNA-binding protein and the dsDNA-dependent fluorescence of an intercalating dye. The DNA sequence selectivity of the probe was characterized, as were the changes in photophysical properties of the dye upon covalent linkage to the peptide to assess whether such bioconjugates could function as molecular probes of gene sequences. The oxazole yellow-peptide bioconjugate exhibits DNA recognition and binding affinity comparable to the native Hin recombinase protein. Examination of photophysical effects to dye conjugation indicates a negligible affect on the fluorescence quantum yield. Fluorescence studies indicate this molecular probe is useful to determine the presence of a given DNA target sequence and gives negligible fluorescence in the absence of a given target site. Using the synthetic route described here, bioconjugates could be designed using different combinations of DNA recognition polypeptides and cyanine dyes to generate an array of sequence specific and wavelength specific probes.

Benzoxazoles↗