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PubMed1980

Search for potential anticonvulsant agents. Synthesis of 2-phenyl/methyl-3-[o-, m- or p-(benzimidazol-2'-yl)phenyl]-6 or 6,8-substituted/unsubstituted quinazolin(3H)-4-ones.

Sixteen new quinazolones were synthesized by the condensation of substituted 4-oxo-3,1-benzoxazines and 2-(o-, m- or p-aminophenyl)benzimidazoles. All the sixteen compounds were tested for anticonvulsant activity in mice against pentylenetetrazole induced convulsions. Except for five compounds in which there was no protection, the others showed protection ranging from 20 to 80%.

Animals↗

PubMed1989

Synthesis and reactions of some biologically active 2-(2'-thienyl)benzoxazinone and quinazolinone derivatives.

Different amines were found to attack the hitherto unknown 6,8-dibromo-2-(2'-thienyl)-3,1-benzoxazin-4(H)-one (2) entirely at position-4, producing the corresponding benzamide derivatives 3a-i. Compound 2 reacted with hydrazoic acid affording the tetrazole 5, beside the benzimidazole derivative 6. Similarly carbon nucleophiles, such as ethyl acetoacetate attack 2 to give 7. 6,8-Dibromo-2(2'-thienyl)-4(3H)-quinazoline and its 3-substituted derivatives 8 a-g were also synthesized. Theoretical calculations for the benzoxazinone 2 and others, based on the simple HMO-method were performed. Close accordance between the theoretically predicted reactivities and the experimental findings was obtained. Biological activities of some of the compounds obtained were also tested.

Anti-Bacterial Agents↗

PubMed1995

The function of 5-HT3 receptors on colonic transit in rats.

The function of serotonin (5-HT)3 receptors on colonic transit was investigated in unanesthetized rats. The colonic transit was accelerated by 5-HT (10 mg/kg, s.c.), 2-methyl-5-HT (30 mg/kg, s.c.), neostigmine (0.03-0.1 mg/kg, s.c.), corticotropin releasing factor (CRF; 1 microgram intracerebroventricular administration) and restraint stress (for 45 minutes). A potent and selective 5-HT3 receptor antagonist, azasetron (+/-)-N-(1-azabicyclo[2.2.2]oct-3-yl)-6-chloro- 4-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-8-carboxamide monohydrochloride ; 0.01-10 mg/kg, p.o. inhibited the 5-HT-, CRF- and stress-accelerated colonic transit in a dose-dependent manner. Ondansetron (10 mg/kg, p.o.) and granisetron (1 mg/kg, p.o) also inhibited the stress-accelerated colonic transit, but azasetron was more effective than these two drugs. Atropine methylbromide (0.1 mg/kg, s.c.) and tetrodotoxin (0.01 mg/kg, s.c.) inhibited the accelerated colonic transit under stress conditions, but methysergide (10 mg/kg, s.c.), SDZ205-557 (10 mg/kg, s.c.), domperidone (30 mg/kg, p.o.), trimebutine (300 mg/kg, p.o.), did not. Azasetron (10 micrograms) administered intracerebroventricularly did not inhibit the stress-induced acceleration. These results suggest that endogenous 5-HT which is released through stress accelerates the colonic transit via the 5-HT3 receptors and finally a cholinergic mechanism. It is considered that azasetron inhibits colonic transit particularly under stress conditions through the blockade of the peripheral 5-HT3 receptors. Azasetron may improve bowel function in stress-related colonic dysfunction like irritable bowel syndrome.

Animals↗

PubMed2003

Synthesis and insecticidal activity of benzoheterocyclic analogues of N'-benzoyl-N-(tert-butyl)benzohydrazide: Part 1. Design of benzoheterocyclic analogues.

The N'-benzoyl group of N-tert-butyl-N'-benzoyl-3,5-dimethylbenzohydrazide (1) was converted to a series of benzoheterocyclecarbonyl groups in order to investigate the potential usefulness of superimposing a hydrazine insecticide on 20-hydroxyecdysone. A series of analogues with benzodioxole, benzodioxane, benzodioxapine, indole, benzoxazole, benzoxazine or benzothiazole instead of the phenyl group of (1) were synthesized and tested for their insecticidal activity against the common cutworm (Spodoptera litura F). N-tert-Butyl-N'-(3,5-dimethylbenzoyl)-1,3-benzodioxole-5-carbohydrazide and N-tert-butyl-N'-(3,5-dimethylbenzoyl)-2,3-dihydro-1,4-benzodioxine-6-carbohydrazide showed high insecticidal activities, superior to that of (1) and equal to that of the commercial insecticide tebufenozide (RH-5992).

Animals↗

PubMed1993

Specific interaction between a novel enediyne chromophore and apoprotein in macromolecular antitumor antibiotic C-1027.

The DNA cleavage experiments show that C-1027 chromophore is selectively incorporated into C-1027 apoprotein and is strongly protected by the apoprotein from loss of its DNA cleaving activity. Fluorescence and circular dichroism spectra reveal (1) important participation of tertiary structure of C-1027 apoprotein for the chromophore binding, (2) specific 1:1 binding of C-1027 chromophore to the apoprotein, and (3) significant interaction of the benzoxazine group in the chromophore-apoprotein complex. On the other hand, C-1027 apoprotein does not contribute to sequence-specificity DNA cleavage by C-1027 antibiotics.

Aminoglycosides↗

PubMed1994

Crystallization and preliminary X-ray diffraction studies on cytosolic (class 1) aldehyde dehydrogenase from sheep liver.

The cytosolic (Class 1) aldehyde dehydrogenase (AlDH) from sheep liver has been crystallized in a form suitable for X-ray diffraction studies. The crystals, grown by vapour diffusion using 6.5 to 7.5% methoxypolyethylene glycol 5000 as precipitant, at pH 6.5, are orthorhombic with cell dimensions a = 80.7, b = 92.5, c = 151.6 A, space-group P2(1)2(1)2(1), and one dimer in the asymmetric unit. The crystals diffract to at least 2.8 A resolution. Although unmodified AlDH crystallized readily, a key factor in obtaining diffraction-quality crystals was the covalent attachment of an active site reporter group, provided by 3,4-dihydro-3-methyl-6-nitro-2H-1,3-benzoxazin-2-one.

Aldehyde Dehydrogenase↗

PubMed2001

Solution structures of C-1027 apoprotein and its complex with the aromatized chromophore.

C-1027 is one of the most potent antitumor antibiotic chromoproteins, and is a 1:1 complex of an enediyne chromophore having DNA-cleaving ability and a carrier apoprotein. The three-dimensional solution structures of the 110 residue (10.5 kDa) C-1027 apoprotein and its complex with the aromatized chromophore have been determined separately by homonuclear two-dimensional nuclear magnetic resonance methods. The apoprotein is mainly composed of three antiparallel beta-sheets: four-stranded beta-sheet (43-45, 52-54; 30-38; 92-94; 104-106), three-stranded beta-sheet (4-6; 17-22; 61-66), and two-stranded beta-sheet (70-72; 83-85). The overall structure of the apoprotein is very similar to those of other chromoprotein apoproteins, such as neocarzinostatin and kedarcidin. A hydrophobic pocket with approximate dimensions of 14 A x 12 A x 8 A is formed by the four-stranded beta-sheet and the three loops (39-42; 75-79; 97-100). The holoprotein (complex form with the aromatized chromophore) structure reveals that the aromatized chromophore is bound to the hydrophobic pocket found in the apoprotein. The benzodihydropentalene core of the chromophore is located in the center of the pocket and other substituents (beta-tyrosine, benzoxazine, and aminosugar moieties) are arranged around the core. Major binding interactions between the apoprotein and the chromophore are likely the hydrophobic contacts between the core of the chromophore and the hydrophobic side-chains of the pocket-forming residues, which is supplemented by salt bridges and/or hydrogen bonds. Based on the holoprotein structure, we propose possible mechanisms for the stabilization and the release of chromophore by the apoprotein.

Actinomycetales↗

PubMed1998

Progress in the development of oxytocin antagonists for use in preterm labor.

There is currently a need for new therapeutic agents for treating preterm labor which could offer improved safety and efficacy beyond what has been achieved with the widely employed beta-mimetics. In this regard, the longstanding hypothesis of oxytocin receptor blockade as representing a potentially more selective method of tocolysis has continued to gain support from results obtained in clinical studies with the peptide oxytocin antagonist, atosiban. Our laboratory has focussed on the identification of non-peptide oxytocin antagonists with properties suitable for both oral and intravenous administration. We have previously described the development of potent, camphor-based oxytocin antagonists, including L-368,899 which entered phase I human studies. More recently we have pursued a new structural class of oxytocin antagonists based on the 1-(N-benzoylpiperidin-4-yl)-4H-3,1-benzoxazin-2(1H)-one template. L-372,662 is a new member of this structural class and in our preclinical assays possesses an attractive overall profile from the standpoint of human oxytocin receptor affinity (Ki = 4.9 nM), human oxytocin vs. vasopressin receptor selectivity (> 500-fold), potency as an antagonist of oxytocin-induced uterine contractions in late gestation pregnant rhesus monkeys (AD50 = 36 micrograms/kg), oral bioavailability (F = 90% in dogs), and aqueous solubility (10 mg/mL).

Animals↗

PubMed2003

Investigation of hydroxamic acids as laccase-mediators for pulp bleaching.

A number of hydroxamic acids have been synthesized and investigated as laccase-mediators for pulp bleaching. As compared with N-hydroxyacetanilide (NHA), one of the most effective laccase-mediators reported so far, N-(4-cyanophenyl)acetohydroxamic acid (NCPA), resulted in the highest brightness and lowest kappa number of hardwood kraft pulp of all the laccase-mediators studied. The bleaching efficacy of a laccase/7-cyano-4-hydroxy-2H-1,4-benzoxazin-3-one system was also comparable with that of a laccase/NHA system. A laccase/NCPA system was further studied for the bleaching of unbleached softwood kraft pulp. The effects of pulp consistency, laccase dosage, NCPA dosage, incubation time, and oxygen pressure on the bleaching efficacy of a laccase/NCPA system were studied.

Acetaminophen↗

PubMed2006

Biochemical features of maize tissues with different capacities to regenerate plants.

Metabolic profiling using GC-MS and LC-MS analyses of soluble metabolites and cell wall bound phenolic compounds from maize calluses of different morphogenic competence revealed a number of biochemical characteristics that distinguish tissues with high plant regeneration ability from tissues that cannot efficiently regenerate plants in vitro. Maize cultures of different ages from H99 (compact type I callus) and HiII (friable type II callus) were divided into two different samples: regenerable (R) and non-regenerable (NR) based on known morphologies. Tissues from both genotypes with high morphogenic potential had higher asparagine and aspartate and indole-3-butenol concentrations, decreased sugar and DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) concentrations, low levels of 4-aminobutyric acid (GABA) and chlorogenic acid and lower levels of feruloyl- and sinapoyl glucosides compared to NR tissues. The ether bound cell wall phenolics of tissues with high regeneration potential had higher levels of the predominant G (guaiacyl) units and lower levels of H (p-hydroxyphenyl) and S (syringyl) units and higher ferulic acid/coumaric acid and ferulic acid/diferulic acid ratios. The same trends were found with the ester-bound phenolics of HiII, however, there were only small differences between the H99 R and NR tissues. Concentrations of the major sugars, organic acids, amino acids and soluble aromatic compounds tended to increase as the time after culture initiation increased. The results show that there are differences in general metabolism, phenolic secondary compounds and cell wall composition between R and NR cell types.

Chromatography, High Pressure Liquid↗

PubMed2000

Purification and characterization of a hydroxamic acid glucoside beta-glucosidase from wheat (Triticum aestivum L.) seedlings.

A beta-glucosidase (EC 3.2.1.21) with a high affinity for cyclic hydroxamic acid beta-D-glucosides was purified from 48-h-old wheat (Triticum aestivum L.) seedlings. The activity occurred transiently at a high level during the non-autotrophic stage of growth, and the nature of the transient occurrence was correlated with that of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc). The glucosidase had maximum activity at an acidic pH (pH 5.5) and the purified enzyme showed a high affinity for DIMBOA-Glc, Vmax and Km being 4100 nkat/mg protein and 0.27 mM, respectively. It also hydrolyzed p-nitrophenol beta-glycosides, as well as flavone and isoflavone glucosides, but to a lesser extent. The results indicated that the primary natural substrate for the glucosidase is DIMBOA-Glc and that the enzyme is involved in defense against pathogens and herbivores in non-autotrophic wheat. The glucosidase was found to be present as oligomeric forms with a molecular mass of 260-300 kDa comprising 60- and 58-kDa monomers. The N-terminal 12-amino-acid sequences of the two monomers were identical (Gly-Thr-Pro-(Ser?)-Lys-Pro-Ala-Glu-Pro-Ile-Gly-Pro), and showed no similarity to those of other plant glucosidases. Polyacrylamide gel electrophoresis under nondenaturing condition indicated the existence of at least eight isozymes. Three cultivars of Triticum aestivum had the same zone of glucosidase activity on zymograms, but the activity zones of the Triticum species, T. aestivum L., T. spelta L. and T. turgidum L., had different mobilities.

Amino Acid Sequence↗

PubMed1986

Inhibition of serine proteases by benzoxazinones: effects of electron withdrawal and 5-substitution.

A series of substituted 4H-3,1-benzoxazin-4-ones have been made and assayed as inhibitors of human leukocyte elastase (HLE) and other serine proteases. The benzoxazinones are kinetically competitive, alternate substrate inhibitors that inhibit by acylation and slow deacylation. Two structure-activity relationships have been found which are consistent with this mechanism. First, electron withdrawal at position 2 gives better inhibition (lower Ki values) because acylation rates are increased while deacylation is relatively unaffected. Second, benzoxazinones with methyl or ethyl substitution at position 5 are better inhibitors of HLE because the acyl enzymes formed from these compounds are 2,6-disubstituted benzoic acid esters and their deacylation is sterically hindered.

Chemical Phenomena↗

PubMed1991

The antiemetic profile of Y-25130, a new selective 5-HT3 receptor antagonist.

Y-25130( (+/-)N-(1-azabicyclo[2.2.2]oct-3-yl)-6-chloro-4-methyl-3-oxo-3,4-dihydro - 2H-1,4-benzoxazine-8-carboxamide hydrochloride) is a potent and selective 5-HT3 receptor antagonist free of dopamine receptor blocking activity. This compound was effective against emesis induced in animals by cytotoxic drugs or by total body X-radiation. When given prophylactically, the doses required to completely inhibit cisplatin-induced emesis in dogs and doxorubicin and cyclophosphamide-induced emesis in ferrets were 0.1 and 0.3 mg/kg i.v., respectively. Y-25130, at the dose of 0.3 mg/kg i.v., almost completely inhibited X-radiation-induced emesis in ferrets. When given during emesis, the doses required to completely inhibit cisplatin-induced emesis in dogs and doxorubicin- and cyclophosphamide-induced emesis in ferrets were 0.1 and 0.3 mg/kg i.v., respectively. The i.v. dose of 0.3 mg/kg of Y-25130 was enough to almost completely inhibit cisplatin-induced emesis in dogs for 24 h. From these results, it is suggested that Y-25130 may become an effective antiemetic drug against emesis induced by anticancer therapy.

Animals↗

PubMed1996

The effects of pharmacological modulation of KATP on the guinea-pig isolated diaphragm.

The purpose of the present study was to investigate the functional consequences of KATP modulation in the normal and the metabolically inhibited guinea-pig isolated diaphragm using the K+ channel openers cromakalim, pinacidil, RP49356 (N-methyl-2-(3-pyridil)-tetrahydrothiopyran-2-carbothiami de-1-oxide) and ZM260384 (2-(2,2-bis(difluoromethyl)-6-nitro-3,4-dihydro-2H-1,4-benzoxazine -4-yl)pyridine-N-oxide) and the K+ channel inhibitors glibenclamide, phentolamine and ciclazindol. All K+ channel openers accelerated the decline in function induced by intermittent tetanic contractions following metabolic inhibition and delayed the development of contracture. Cromakalim also improved the recovery of twitch tension following 10 min intermittent tetanic stimulation in the hypoxic guinea-pig diaphragm preparation. Of the K+ channel inhibitors tested, only ciclazindol, at the highest concentration tested (10 microM), significantly delayed the decline in tetanic tension following metabolic inhibition in the guinea-pig isolated diaphragm. None of the inhibitors significantly accelerated the development of contracture. All inhibitors however, antagonised the actions of the K+ channel opener, cromakalim. The results indicate that opening of KATP can accelerate the decline in function following metabolic inhibition in the guinea-pig isolated diaphragm. In the absence of K+ channel openers however, KATP does not appear to contribute to this decline under the conditions of the present study.

Adenosine Triphosphate↗

PubMed1995

Analysis of mycolic acids by high-performance liquid chromatography and fluorimetric detection. Implications for the identification of mycobacteria in clinical samples.

Mycolic acids from Mycobacterium phlei and M. bovis cell wall skeletons (CWSs) were analyzed by HPLC. After saponifying lyophilized CWSs in methanolic KOH, the mycolic acids were quantitatively extracted into chloroform. Aliquots of the CWS mycolic acid extracts were then derivatized prior to HPLC analysis with a UV reagent, p-bromophenacylbromide (PBPB), and three fluorescent reagents, 4-bromomethyl-6,7-dimethoxycoumarin, 4-bromomethyl-7-acetoxycoumarin and 3-bromomethyl-7-methoxy-1,4-benzoxazin-2-one. A synthetic alpha-branched carboxylic acid was derivatized with the same reagents and used as an internal standard along with the mycolic acids. The derivatized samples were analyzed by reversed-phase HPLC on a Waters Novapak C18, 4 microns particle size, 150 mm x 3.9 mm stainless-steel column. Two solvent systems were used: (1) methanol and methylene chloride with the column at 30 degrees C, and (2) methanol and isopropanol with the column at 50 degrees C. Detection sensitivity with the fluorescent reagents was 16-50 times greater than the sensitivity observed with PBPB-derivatized samples. Unique mycolic acid elution profiles for the two mycobacterial species could be achieved with each of the solvent systems and derivatization reagents tested. Thus, the HPLC analysis of pre-column derivatized mycolic acids was useful as a means of rapidly identifying mycobacterial species. Replacement of methylene chloride with isopropanol and PBPB with a fluorescent derivatizing reagent could increase the safety and sensitivity of the assay, and make it more useful for the clinical identification of mycobacterial infections.

Cell Wall↗

PubMed1996

Chemistry of biologically active benzoxazinoids.

2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and its desmethoxy derivative (DIBOA) are major allelochemicals produced by corn, wheat, rye and related monocotyledons. These benzoxazinone derivatives have a wide variety of biological actions, including antifungal and mutagenic activities. Structure-activity relationships of these compounds and their derivatives (benzoxazinoids), the reactivity of benzoxazinoids with nucleophiles, and the substituent effects of the 7-methoxy and 2-hydroxy groups are discussed in relation to the molecular mechanisms of the biological activities.

Oxazines↗

PubMed1991

Genotoxic evaluation of letimide with the mouse bone marrow micronucleus test.

Letimide, 3[2-(diethylamino)ethyl]-2H-1,3-benzoxazine-2,4(3H)-dione, a new analgesic, is a cyclic derivative of a salicylamide with a higher pharmacological potency than acetylsalicylic acid. In this study we evaluated its clastogenic activity using the micronucleus test in vivo. Our results did not show any clastogenic effect produced by letimide as compared with control mice and animals treated with cyclophosphamide.

Animals↗

PubMed2004

Microbial transformation products of benzoxazolinone and benzoxazinone allelochemicals--a review.

Cyclic hydroxamic acids and lactams are allelochemicals present in the common agricultural crops wheat, rye, and maize. The hydroxamic acids are mainly present in the plants as glucosides. Upon injury or insect attack or when exuded to the soil environment, the hydroxamic acids occur in their unstable agluconic form. In the first step in the transformation of hydroxamic acids, benzoxazolinones are formed spontaneously. It is necessary to elucidate the further microbial transformation of these compounds in the soil environment for a purposeful exploitation of the allelopathic properties of wheat, rye, and maize. In the present paper, the existing knowledge on microbial transformation products of benzoxazolin-2-one (BOA), 6-methoxy-benzoxazolin-2-one (MBOA), and 2-hydroxy-1,4-benzoxazin-3-one (HBOA) was reviewed. Three main groups of transformation products were identified: aminophenoxazinones, malonamic acids, and acetamides. Future research needs concerning the transformation of these chemicals in soil are discussed, when their properties for suppressing weeds and soil-borne diseases are going to be exploited.

Acetamides↗