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

Protection against cocaine toxicity in mice by the dopamine D3/D2 agonist R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol [(+)-PD 128,907].

Cocaine abuse is a public health concern with seizures and death being one consequence of overdose. In the present study, dopamine D(3/)D(2) receptor agonists dose dependently and completely prevented the convulsant and lethal effects of cocaine. The D(3)-preferring agonists R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol) [(+)-PD 128,907], (+)-7-hydroxy-dipropylaminotetralin, and the mixed D(3/)D(2) agonists quinpirole and quinelorane were all effective against cocaine toxicity in mice. The anticonvulsant effects of these compounds occurred at doses below those that produced motor impairment as assessed in the inverted screen test. Protection against the convulsant effects of the selective dopamine uptake inhibitor 1-[2-[bis(4-fluorophenyl)methoxy] ethyl]-4-[3-phenyl-propyl]piperazine (GBR 12909) was also conferred by (+)-PD 128,907. The possible selectivity of the effects of (+)-PD 128,907 (3 mg/kg) for these dopaminergic compounds was demonstrated by its general lack of protective efficacy against a host of convulsants acting through other neural mechanisms [pentylenetetrazol, (+)-bicuculline, and picrotoxin, 4-aminopyridine, and t-butylbiclyclophosphoorothionate, N-methyl-d-aspartate, kainate, pilocarpine, nicotine, strychnine, aminophylline, threshold electric shock, and 6-Hz electrical stimulation]. Direct and correlational evidence suggests that these effects were mediated by D(3) receptors. Protection was stereospecific and reversible by an antagonist of D(3) receptors [3-[4[1-(4-[2[4-(3-diethyamino-propoxy)-phenyl]-benzoimidazol-l-yl]-butyl)-1H-benzoimidazol-2-yl]-phenoxy]-propyl)-diethyl-amine; PD 58491] but not D(2) receptors [3[[4-(4-chlorophenyl)-4 hydroxypipeidin-1-yl]methyl-1H-indole; L-741,626]. Anticonvulsant potencies were positively associated with potencies in a functional assay of D(3) but not D(2) receptor function. Together, these findings suggest that the prevention of cocaine convulsions and lethality by (+)-PD 128,907 may be due to D(3) receptor-mediated events.

Animals↗
PubMed1994

Synthetic approaches to 3-amino-1,4-naphthoquinone-2-carboxylic acid derivatives and photochemical synthesis of novel 1,4,5,10-tetrahydro-5,10-dioxo-2H-naphth[2,3-d][1,3]oxazine derivatives.

Synthesis of 3-alkylamino-1,4-naphthoquinone-2-carboxylic acid (2) was attempted. Although 3-(1-piperidinyl)-1,4-naphthoquinone-2-carboxylic acid (2a) was not obtained, probably because of its instability, the esters (18a, b) of 2a could be prepared. 2-Alkylamino-3-hydroxymethyl-1,4-naphthoquinones (9a-g) were photochemically cyclized to the 1,4,5,10-tetrahydro-5,10-2H-naphth[2,3-d][1,3]oxazines (19a-g), containing a novel heterocyclic ring system in moderate yields. Anti-bacterial activity of the prepared compounds was weak or insignificant.

Anti-Bacterial Agents↗
PubMed1997

Synthesis and pharmacological evaluation in mice of new non-classical antinociceptive agents, 5-(4-arylpiperazin-1-yl)-4-benzyl-1,2-oxazin-6-ones.

Several 5-(4-arylpiperazin-1-yl)-4-benzyl-1,2-oxazin-6-ones have been synthesized and tested for analgesic activity in a visceral pain model (phenylbenzoquinone-induced writhing test = PBQ test). A good correlation has been found between the antinociceptive effects of drugs and both their lipophilic and steric properties. The most active derivatives 5c and 5f, with intraperitoneal ED50 values of 10.5 and 10.3 mg kg-1 respectively, were more extensively investigated by evaluating their analgesic activity in a somatosensory pain model (hot plate test), as well as their sedative properties. Furthermore, naloxone suppressed the effect of 5c and 5f in the PBQ test, though these derivatives were ineffective to potentiate morphine analgesia. Pretreatment with yohimbine did not significantly attenuate the analgesic effects of 5c and 5f. In addition, pretreatment with 5-hydroxytryptophan associated with carbidopa also failed to potentiate the antinociceptive effects of 5c and 5f. So, a part of the analgesic activity of 5c and 5f seems to be related to an opioidergic mechanisms, especially at the mu receptor level. Molecular modeling studies performed on the opiate drug morphine and on the most stable conformer of 5f showed structural similarities between these two molecules.

Analgesics↗
PubMed1994

[Reaction of 3-aryl-2-nitroacrylates with titanium tetrachloride. Formation of 4H-1,2-oxazines and hydroxy-arylaldehydes].

The reaction of ethyl 3-aryl-2-nitroacrylate (1a: aryl = 3-methoxyphenyl) with toluene in the presence of titanium tetrachloride gave 4-(4'-methyl-phenyl)-4H-1,2-benzoxazine (3) in a 44.2% yield. The acrylate 1a reacted with dichloromethane in the presence of titanium tetrachloride to give 5-methoxy-salicylaldehyde (2a) in a 61.8% yield. Therefore, 2a was presumed to be formed via an intermediate 4H-1,2-benzoxazine (3'), followed by ring opening to quinone methide and cyano formate. In a similar reaction using both toluene and dichloromethane, 1 bearing a 2-naphthyl group gave a dimer of quinone methide and 1-hydroxy-2-naphthaldehyde via 4H-naphth[2,1-e]-1,2-oxazine, respectively.

Acrylates↗
PubMed2005

Absorption and fluorescence spectroscopic study on complexation of Oxazine 1 Dye by calix[8]arenesulfonate.

It has been established by combined absorption and fluorescence measurements that the cationic dye Oxazine 1 (OX) and the polyvalent anionic host calix[8]arenesulfonate (SCA8) form two complexes in simultaneous reactions: OX + SCA8 <--> OX.SCA8 (1), and OX.SCA8 + OX <--> OX(2).SCA8 (2). The equilibrium constants for the two reactions, as functions of the ionic strength (I), and the absorption and fluorescence spectra of the two complex species have been determined by a least-squares fitting method from the experimental data. The variations of the binding constants with the ionic strength could be described on the basis of Debye-Huckel theory. The equilibrium constants are large; their values extrapolated to I = 0 are K(1) = 5.5 x 10(6) M(-1) and K(2) = 4.4 x 10(5) M(-1). The fluorescence of OX undergoes a strong static quenching upon complexation. These results indicate that the complexes are held together by strong electrostatic forces. The addition of non-fluorescent tetramethylammonium chloride to OX-SCA8 mixtures results in a dramatic fluorescent enhancement, which demonstrates the potential applicability of this supramolecular system in fluorescence assays.

Calixarenes↗
PubMed1992

[Synthesis of N-(2-carboxy-thieno(2,3-b)pyridin-3-yl)-amidines by the reaction with 4-oxo-4H-pyrido(3',2':4,5)-thieno(3,2-d)-1,3-oxazines with secondary cycloaliphatic amines].

4-Oxo-4H-pyrido[3',2':4,5]thieno[3,2-d]1,3-oxazines react with secondary cycloaliphatic amines to give besides the expected bisamides the amine salts of N-(2-carboxy-thieno[2,3-b]pyridine-3-yl)amidines. These compounds showed inhibitory activity against different lipoxygenases, but a small chemical stability.

Amidines↗
PubMedDate not supplied

Researches on antiinflammatory agents. Studies on some 1-methyl- or 1-phenyl-6-(2-substitutedphenyl)-pyrazolo[3,4-d]-1,3-oxazin-4(1H)-ones.

Following our research on analgesic and antiinflammatory active compounds containing the pyrazole nucleus, a number of new 1-methyl- or 1-phenyl-6-(2-substitutedphenyl)-pyrazolo[3,4-d]-1,3-oxazin- 4(1H)-ones was synthesized and tested, together with a few analogues previously obtained, for their analgesic and antiinflammatory activities, as well as for their acute toxicity and ulcerogenic effects. One of the tested compounds showed activity comparable to that of phenylbutazone and, at the same time, higher LD50 and a very low ulceration index.

Analgesics↗
PubMed1983

[Synthesis, conformation and pharmacological effect of some stereoisomeric condensed 1,3-oxazine-4-ones. 44: Stereochemical studies; 22: Saturated heterocycles].

It has been reported the synthesis, examination of the stereochemistry and biological effect of 2-substituted-cis-5,6-trimethylen-, cis- and trans-5,6-tetramethylene and -5,6-pentamethylene-2,3,5,6-tetrahydro-1,3-oxazine-4-one derivatives. Primarily cis-isomers were synthetized because in the pharmacological test systems the trans isomers were less active. The compounds tested have an antiphlogistic effect of different intrinsic activity.

Animals↗
PubMed1978

Testing of 2,3-dihydro-1,3-6H-oxazine-dione (3-oxauracil) in mouse L1210 leukemia and 37 sarcoma.

The antimetabolite 2,3-dihydro-1,3-6H-oxazine-dione (3-oxauracil) has been investigated in an attempt to elucidate its effects on survival time of DBA/2 and B6D2F1 mice with L1210 leukemia and of outbred albino mice with 37 sarcoma. A significant increase in survival time was observed in mice with 37 sarcoma and slight effects were observed in mice with L1210 leukemia when treated with 3 x 12.5 or 3 x 25 mg/kg of 3-oxauracil. No toxic side effects were observed when large therapeutic doses of the drug were given.

Animals↗
PubMed1994

[Synthesis of tert-butylcyclopentane-fused 1,3-oxazines and 1,3-thiazines].

Chlorosulphonyl isocyanate (CSI) addition to 4-tert-butylcyclopentene furnished the azetidinone (3) in a stereospecific reaction. Azetidinone 3 was transformed by ring opening esterification and lithium aluminium hydride (LAH) reduction to the 2-hydroxy-methyl-4-tert-butyl-1-cyclopentylamine (6). The N-methyl-aminoalcohol (8) was prepared from amino esters (5) with ethyl chloroformate and subsequent LAH reduction. By different ring-closure methods, a number of tert-butyl-cyclopentante-fused 1,3-oxazines and 1,3-thiazines were synthesized. A comparative study of the prepared compounds was performed by IR, 1H- and 13C-NMR, DEPT and DNOE measurements.

Indicators and Reagents↗
PubMedDate not supplied

1H, (13)C, and (15)N NMR stereochemical study of cis-fused 7a(8a)-methyl and 6-phenyl octa(hexa)hydrocyclopenta[d][1,3]oxazines and [3,1]benzoxazines.

Four 7a-methyl octa(or hexa)hydrocyclopenta[d][1,3]oxazines, five 8a-methyl octa(or hexa)hydro[3,1]benzoxazines, two 6-phenyl hexahydro[3,1]benzoxazinones, and 8a-methyl hexahydro[1,3]benzoxazinone, all cis-fused, were prepared and their stereostructures studied by various one- and two-dimensional (1)H, (13)C, and (15)N NMR spectroscopic methods. In solution, the cyclopentane-fused 2-oxo derivatives and the 1,3-benzoxazinone were found to attain exclusively the N-in/O-in conformation, whereas the 6-phenyl 2-oxo/thioxo derivatives were found to be present predominantly in the N-out conformation. The C-2 unsubstituted and the 2-oxo/thioxo 7a/8a-methyl derivatives were all present in solution as a rapidly interconverting equilibrium of the N-in and N-out conformations. The C-2 methyl derivatives were each found to be interconvertable mixtures of epimers (at C-2) with the N-in conformer predominating for one epimer and the N-out conformer predominating for the other, with both predominating conformers having the C-2 methyl group equatorially orientated. The substituent on the nitrogen (H or Me) was found to be always predominantly equatorial with respect to the heteroring, except for the epimeric 2-methyl derivatives with N-out conformations where steric constraints and the generalized anomeric effect resulted in the axial orientation of the C-2 methyl being favored.

Journal Article↗
PubMed1980

Behavioural tests in peri- and post-natal toxicity study in rats of trithiozine (Tresanil) [4-(3,4,5-trimethoxythiobenzoyl)-tetrahydro-1,4-oxazine].

During the biological research on trithiozine [4-(3,4,5-trimethoxythiobenzoyl)-tetrahydro-1,4-oxazine], a substance with gastric antisecretory action, a study on peri- and post-natal toxicity was conducted in rats, during which an attempt was made to set up a series of tests which would consist of the study of the behaviour of offspring in their first 21 days of life. To confirm the validity of these tests, a parallel peri- and post-natal toxicity study was carried out with two compounds phenobarbital and diazepam, known to be active on the CNS and likewise known to pass from plasma into milk. The three compounds in question were administered by the oral route to pregnant rats from the 15th day of pregnancy to the 20th day after delivery in the following dosages; trithiozine: 100-200-500 mg/kg/day, phenobarbital: 60-100 mg/kg/day, diazepam: 30-60 mg/kg/day. The offspring were submitted, between their 14th and 20th day of life to the cheminée test, traction test, righting reflex test and avoidance test. The cheminée and avoidance tests proved to be the most suitable for studying neonatal behaviour. The percentage of success in these two tests decreased in a statistically significant manner for the groups treated with phenobarbital and diazepam, while trithiozine did not produce any variations in neonatal behaviour.

Animals↗
PubMed2006

Energy transfer between rhodamine 3B and oxazine 4 in synthetic-saponite dispersions and films.

The objective of this study was the investigation of energy transfer between the laser dyes rhodamine 3B (R3B) and oxazine 4 (Ox4) adsorbed on the surface of synthetic Sumecton saponite (Sum). The process of energy transfer was studied for both saponite dispersions and oriented solid films. The electronic properties, luminescence, and the energy transfer process were described by UV-vis absorption and fluorescence spectroscopy. For the efficiency of the energy transfer process, the concentrations of energy donor and acceptor components on a clay mineral surface were found to be essential. A side reaction of the molecular assembly formation reduced both the luminescence and energy-transfer yields, mainly due to fluorescence quenching. The quenching was more problematic for the solid film specimens, where an appropriate modification of the inorganic host with hydrophobic alkylammonium cations was used to achieve a higher luminescence. Due to the higher tendency of Ox4 to form nonluminescent aggregates at higher concentrations, the lowering of the Ox4 concentration further improved the luminescent properties of the films. In this case, the energy transfer occurring in the solid film from R3B to Ox4 was clearly proven.

Journal Article↗
PubMed2003

Modeling NMR parameters by DFT methods as an aid to the conformational analysis of cis-fused 7a(8a)-methyl octa(hexa)hydrocyclopenta[d][1,3]oxazines and [3,1]benzoxazines.

The energies of the preferred conformations of four 7a-methyl octa(or hexa)hydrocyclopenta[d][1,3]oxazines, five 8a-methyl octa(or hexa)hydro[3,1]benzoxazines, and 8a-methyl hexahydro[1,3]benzoxazinone, all cis-fused, were investigated by DFT methods. Following geometry optimization at the B3LYP/6-31G(d,p) level, both the proton chemical shifts and the vicinal coupling constants between H-4a and the H-4 and H-5 protons were calculated at the B3LYP/cc-pVTZ level and compared to the previously experimentally measured values. The agreement between the calculated and the experimental chemical shifts was found to be good. Similarly, the agreement between the calculated and the experimental vicinal coupling constants was also found to be good, thus providing a methodology for determining the conformational equilibria of such systems that is comparable in many respects to experimental approaches such as variable-temperature NMR or to the use of model coupling constant values, when available, from analogous compounds.

Journal Article↗
PubMed2000

Design, synthesis, and 1,3-dipolar cycloaddition of (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1,4-oxazin-2-one N-oxides as chiral (E)-geometry-fixed alpha-alkoxycarbonylnitrones.

Optically pure (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1, 4-oxazin-2-one N-oxides [(5R)- and (5S)-2] were designed as chiral (E)-geometry-fixed alpha-alkoxycarbonylnitrones 1. The nitrones (5R)- and (5S)-2 were synthesized by three-step oxidation of (R)- and (S)-phenylglycinols [(R)- and (S)-3], condensation of the resulting (R)- and (S)-2-hydroxylamino-2-phenylethanols [(R)- and (S)-5] with glyoxylic acid, and cyclization of the intermediary nitrones (R)- and (S)-6b. The nitrone (5R)-2reacted with olefins 7-14 under mild conditions to afford the corresponding cycloadducts 15-22 as the main products via the least sterically demanding exo modes. Cycloadduct 30 obtained from (5S)-2 and cyclopentadiene was effectively elaborated to (1S,4S, 5R)-4-benzyloxycarbonylamino-2-oxabicyclo[3.3.0]oct-7-en-3-one (28), the key synthetic intermediate of carbocyclic polyoxin C.

Journal Article↗