Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pyrans”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2003

Design, synthesis, and activity of novel cis- and trans-3,6-disubstituted pyran biomimetics of 3,6-disubstituted piperidine as potential ligands for the dopamine transporter.

In our effort to develop novel molecules for the dopamine transporter, we converted our previously designed dopamine transporter specific 3,6-disubstituted piperidine template into corresponding pyran derivatives. cis-Pyran derivative 7b, like their piperidine counterparts, exhibited greater activity for the dopamine transporter compared to the trans-isomer. Further molecular modifications of the cis derivative led to the development of potent analogues which indicated successful bioisosteric replacement of the piperidine ring by a pyran moiety in these 3,6-disubstituted derivatives.

Animals↗
PubMed1974

Inhibition of RNA-dependent DNA polymerase of avian myeloblastosis virus by pyran copolymer.

PYRAN COPOLYMER, A KNOWN IMMUNOSTIMULATOR, WAS FOUND TO BE A POTENT INHIBITOR OF PURIFIED DNA POLYMERASE (DEOXYNUCLEOSIDETRIPHOSPHATE: DNA deoxynucleotidyltransferase; EC 2.7.7.7) isolated from avian myeloblastosis virus. Unlike other inhibitors, pyran showed unique features of inhibition. It interacts with the polymerase at a region other than the template site. The inhibitory effect was overcome only by excess enzyme and not affected by excess template. The degree of inhibition was not template specific for the templates tested: 70S RNA from avian myeloblastosis virus, synthetic hybrid poly(rA).oligo(dT)(10), synthetic copolymer poly(dA-dT), and activated calf-thymus DNA. The observed rate of inhibition by pyran was shown to vary with the different polymerases tested. Inhibition was shown with all oncornaviral polymerases and, to a lesser extent, with mammalian polymerases. However, two of the three bacterial polymerases, by contrast, showed a marked activation.

Adenine Nucleotides↗
PubMed1975

Decrease in experimental liver metastasis in mice after treatment with pyran copolymer.

Intravenous injection of pyran copolymer (divinyl ether-maleic anhydride) 24 h prior to intravenous injection of B16 melanoma in C57/BL6 mice greatly decreased the number of liver metastases. If the pyran copolymer was administered 3 days after injection of tumor cells, the number of metastases was not significantly decreased. Pyran copolymer has been reported to stimulate interferon production and increase clearance of particulate matter by the reticuloendothelial system. The results of this experiment suggests an important role played by the reticuloendothelial system in experimental liver metastasis.

Animals↗
PubMed2002

[Synthesis, structure and stability of 4-aryl-4H-pyran-3,5-dicarboxylic acid esters].

Eight new 4-aryl-2,6-dimethyl-4H-pyrane-3,5-dicarboxylic acid esters 2 and a new 2-amino-2-nor derivative 7 are synthesized using known methods, whose limitations are shown. In contrast to the isoelectronic 4-aryl-1,4-dihydro-pyridines (DHP) 1 the compounds 2e, g possess a nearly planar heterocycle, as found by X-ray crystal structure analysis. The 4H-pyrane-3,5-dicarboxylic acid ester 2e with m-substitution exhibits s-cis/s-cis-conformation, while compound 2g with o-substitution of the aromatic ring represents s-cis/s-trans-conformation. The half-wave potentials (E1/2) show that 4H-pyranes are more stable than the DHP 1. The substitution of the 4-phenyl ring with an electron donating group decreases the potential considerably, whereas an electron acceptor group slightly increases the potential. Replacement of the 2-methyl group by the amino function causes a dramatic loss of stability.

Crystallography, X-Ray↗
PubMed1979

Mobilization of murine hemopoietic stem cells (HSC) by Pyran Copolymer.

Pyran Copolymer, divinyl-ether maleic anhydride increases the concentration of circulating pluripotential stem cells in mice by a factor of 15 to 30. Maximal mobilization occurs five days after Pyran Copolymer injection with synchronous peaks of CFU-S and CFU-C. When Pyran fractions of defined molecular weight from 12,000 to 52,000 are injected into mice, mobilization of CFU-S and CFU-C parallels molecular weight. Hemopoietic stem cells are mobilized from bone marrow into peripheral blood and subsequently trapped in the spleen.

Animals↗
PubMed1979

Enhancement of erythroid target cells for Friend murine leukemia virus by intravenous pyran treatment.

Male BALB/c mice that received prophylactic iv treatment with pyran had significantly enhanced splenomegaly, an increased number of splenic foci induced by the spleen focus forming virus (SFFV) in the Friend murine leukemia virus (F-MuLV) complex, and a slightly decreased mean survival time as compared with untreated controls infected with F-MuLV. A corresponding increase in the lymphatic leukemia virus component of the F-MuLV complex was not observed, which suggests that the enhancement of the disease was due primarily to a selective increase in the SFFV component of the F-MuLV complex. That the enhancement was related to an increased number of target cells for SFFV was substantiated by data concerning erythropoiesis in iv pyran-treated animals. Increases in splenic hematocrits and in uptake of 59Fe in the spleens of animals treated iv with pyran provided quantitative evidence for the histologic finding of increased erythroid precursors in the spleens.

Animals↗
PubMed1979

[Chemical and pharmacological research on pyran derivatives. XIV. 3-alkylaminoaphtho/2,1-b/pyran-1-ones and derivatives].

3-Alkyl(phenyl)aminoaphtho[2,1-b]pyran-1-ones (III) were prepared from N-alkyl or N-phenylethoxycarbonylacetamides and 2-naphthol in the presence of phosphorus oxychloride, in order to evaluate their pharmacological activity on the CNS in comparison with previously described 3-dialkylaminoaphtho[2,1-b]pyran-1-ones. Compounds (III) gave 2-morpholinomethyl derivatives as well as N-acetyl and N-ethtoxycarbonyl derivatives. The reaction of (III) in which R = alkyl and N,N-dimethylformamide-POCl3 afforded 2-formyl derivatives and in some cases also 8-alkyl-9,10-bisdimethylaminoaphtho[1',2':5,6]pyrano[2,3-b]pyrrol-11(8H)-ones; when R = phenyl, only naphtho[1',2':5,6]pyrano[2,3-b]quinolin-14-one was obtained from the same reaction. Pharmacological evaluation showed that compounds (III) had a weak CNS depressant activity. Some of them also exhibited antagonist effect on reserpine-induced blepharospasm and hypothermia and on metrazole-induced seizures in the mouse. Within the limits of these activities a special behavior was found for the compound 3-ethylaminoaphtho[2,1-b]pyran-1-one [(III b) - K 12479].

Amphetamines↗
PubMed1984

Effects of 5-aza-2'-deoxycytidine in combination with the biochemical modulator thymidine or the immune modulator pyran copolymer on L1210 leukemia-bearing mice.

The purpose of these studies was to investigate the potential modulation by thymidine in vivo of the antitumor action of 5-aza-2'-deoxycytidine (DAC). During the course of these investigations it was observed that DAC given as a single dose to mice bearing late L1210 tumor resulted in cell kills estimated to be close to 6 logs. Because of the potentially large antigen load released by such a cell kill, the immune modulator pyran copolymer was also tested in combination with DAC. Thymidine increased the cytotoxicity of DAC but not in a selective fashion. Doses of DAC in combination with thymidine were more toxic to host mice than equivalent doses of DAC alone, but no therapeutic benefit was apparent with this combination at maximally tolerated doses. A single dose of pyran copolymer and DAC appears to result in an adjuvant action that eliminates the few remaining L1210 cells refractory to DAC chemotherapy. Doses of DAC alone that result in lengthy increases in survival times but no cures resulted in a substantial number of cures when used in combination with pyran copolymer.

Animals↗
PubMed1977

[Chemical and pharmacological research on pyran derivatives. VII. Derivatives of naphto/1',2':5,6/pyran/2,3-c/pyrazole and of 12H-naphto/1',2':5,6/pyran/2,3-d/pyrimidine].

Reaction of substituted 1-oxo-3-dialkylamino-1H-naphtho[2,1-b]pyrans with N,N-dimethylformamide in the presence of phosphorus oxychloride afforded the corresponding substituted 1-oxo-2-formyl-3-dialkyl-amino-1H-naphtho[2,1-b]pyrans. Condensation of substituted 1-oxo-2-formyl-3-dimethylamino-1H-naphtho[2,1-b]pyrans with hydrazine or monosubstituted hydrazines led to the formation of 11-oxo-8H,11H-naphtho[1',2':5,6]pyrano[2,3-c]pyrazole derivatives through the intermediate hydrazones and subsequent cyclization. Similarly, condensation with acetamidine or guanidine gave rise to the formation of 12-oxo-12H-naphtho[1',2':5,6]pyrano[2,3-d]pyrimidine derivatives. Some of these compounds were tested for their pharmacological properties, but no noteworthy activity was observed.

Animals↗
PubMed1977

Reaction of dichloroketene and sulfene with N,N-disubstituted 6-aminomethylene-5,6,8,9-tetrahydro-7H-benzocyclohepten-7-ones. Synthesis of 5H-benzo(5,6)cyclohepta(2,1-b)pyran and 5H-benzo(5,6)cyclohepta(1,2-e)-1,2-oxathiin derivatives.

The 1,4-cycloaddition of dichloroketene to N,N-disubstituted 6-aminomethylene-5,6,8,9-tetrahydro-7H-benzocyclohepten-7-ones afforded N,N-disubstituted 4-amino-3,3-dichloro-3,4,10,11-tetrahydro-5H-benzo[5,6]cyclohepta[2,1-b]pyran-2-ones only in the case of full or partial aromatic N-substitution. The relative adducts gave N,N-disubstituted 4-amino-3-chloro-10,11-dihydro-5H-benzo[5,6]cyclohepta[2,1-b]pyran-2-ones by dehydrochlorination. The 1,4-cycloaddition with sulfene occurred readily in the case of both aliphatic and aromatic N-substitution to give N,N-disubstituted 4-amino-3,4,10,11-tetrahydro-5H-benzo[5,6]cyclohepta[1,2-e]-1,2-oxathiin-2,2-dioxides. These compounds, as well as the pyran derivatives, can be considered as linear heterocyclic analogues of the Amitriptyline ring system.

Cycloheptanes↗
PubMedDate not supplied

Mutagenicity of K-region derivatives of 1-nitropyrene; remarkable activity of 1- and 3-nitro-5H-phenanthro[4,5-bcd]pyran-5-one.

The mutagenic activities toward S. typhimurium strains TA98 and TA100 of K-region derivatives of 1-nitropyrene and pyrene were determined. The compounds tested were trans-4,5-dihydro-4,5-dihydroxy-1-nitropyrene (Compound 3), trans-4,5-dihydro-4,5-dihydroxypyrene (Compound 4), 1-nitropyrene-4,5-quinone (Compound 5), 1-nitropyrene-9,10-quinone (Compound 6), pyrene-4,5-quinone (Compound 7), and the lactones, 1-nitro-5H-phenanthro[4,5-bcd]pyran-5-one (Compound 8), 3-nitro-5H-phenanthro[4,5-bcd]pyran-5-one (Compound 9), and 5H-phenanthro[4,5-bcd]pyran-5-one (Compound 10). Neither pyrene nor any of its K-region derivatives was mutagenic, either in the absence or presence of S9 mix at the doses tested. Of the K-region derivatives of 1-nitropyrene, the lactones (Compounds 8 and 9) were generally the most active; 0.25 microgram/plate induced 900-2200 revertants in TA98 or TA100 without activation. The 4,5-dihydrodiol (Compound 3), an established mammalian metabolite of 1-nitropyrene, was less mutagenic than was 1-nitropyrene in TA98, but was more mutagenic than was 1-nitropyrene in TA100, regardless of the presence of S9 mix. The quinones (Compounds 5 and 6) were less mutagenic than was 1-nitropyrene in the absence of S9 mix in both strains, but their activities were increased in the presence of S9 mix. The mutagenic activities of the lactones (Compounds 8 and 9) were lower in strains TA98NR and TA98/1,8-DNP6 than in TA98, indicating that nitro-reduction and esterification are involved in their activation. The results of this study indicate that K-region derivatives of 1-nitropyrene may be important in its metabolic activation.

Animals↗
PubMed1999

Chemical modification of apomorphine to discover sigma ligands: 6H-dibenzo[b,d]pyran and carbazole analogues.

It seems that many sigma ligands have been designed from known sigma ligands. We focused on a difference in structural flexibility between haloperidol and apomorphine, and studied chemical modification of apomorphine, a compound with high affinity for dopamine D2 receptors but not for sigma receptors, for discovery of sigma ligands. The first modification yielded good results with 6H-dibenzo[b,d]pyran analogues with weak affinity for sigma receptors but not D2 receptors. Furthermore, carbazole analogues, compounds designed from 6H-dibenzo[b,d]pyran analogues, potentially acted at sigma receptors with high selectivity. This paper describes the design, synthesis and sigma/D2 selectivity of 6H-dibenzo[b,d]pyran and carbazole analogues.

Animals↗
PubMed2002

Synthesis of 6H-dibenzo[b,d]pyran-6-ones from aryl 3-bromopropenoates via a sequential one-pot procedure using the Sonogashira coupling-benzannulation reaction.

Various kinds of 6H-dibenzo[b,d]pyran-6-ones 4 were synthesized via a sequential one-pot procedure using the Sonogashira coupling-benzannulation reaction of aryl 3-bromopropenoates 1, in which the ortho-position of aryl group is substituted with enynes or iodine, with acetylenes 2 in the presence of palladium and copper catalysts. The Sonogashira coupling between the aryl 3-bromopropenoates 1a and 1b, bearing enynes at the ortho-position of aryl group, and alkynes 2a-g gave the enyne intermediates 3 in situ, which subsequently underwent the palladium-catalyzed benzannulation reaction to afford the 6H-dibenzo[b,d]pyran-6-ones 5a-g and 6. The Sonogashira coupling between the aryl 3-bromopropenoate 1c, bearing iodine at the ortho-position of aryl group, and diynes 2f and 2h produced the diyne intermediates 13, which underwent the benzannulation reaction to afford the 6H-dibenzo[b,d]pyran-6-ones 14f and 14h.

Journal Article↗
PubMed1996

Addition-Rearrangement of Aryl- and Alkoxysulfonyl Isocyanates with 5-Methyl-Substituted 3,4-Dihydro-2-methoxy-2H-pyrans. Selective Synthesis of Functionalized 2-Piperidones(1).

3,4-Dihydro-2-methoxy-5-methyl-2H-pyran and 3,4-dihydro-2-methoxy-5,6-dimethyl-2H-pyran undergo addition-rearrangement reactions with arylsulfonyl isocyanates to generate the corresponding 3-formyl- and 3-acetyl-6-methoxy-3-methyl-1-(arylsulfonyl)-2-piperidones. For example, 3,4-dihydro-2-methoxy-5-methyl-2H-pyran and phenylsulfonyl isocyanate afforded 3-formyl-6-methoxy-3-methyl-1-(phenylsulfonyl)-2-piperidone as a separable trans/cis mixture in high yield. The more reactive phenoxysulfonyl and alkoxysulfonyl isocyanates provided analogous results.

Journal Article↗
PubMed1975

Affinity chromatography of viral DNA polymerases on pyran-sepharose.

Pyran covalently linked to cyanogen bromide-activated Sepharose has been shown to be an effective affinity matrix for several viral DNA polymerases. Differential salt elution of viral compared with cellular polymerases, as well as substrate elution, suggests the affinity nature for the matrix. Unlike some other affinity systems described, pyran-Sepharose is totally resistant to nuclease digestion and is stable at 4 degrees for several months. DNA polymerases isolated from several viruses by detergent treatment were recovered in good yield. Analysis of iodinated proteins by sodium dodecyl sulfate-gel electrophoresis revealed that the DNA polymerase of avian myeloblastosis virus found in crude preparations of the virus could be purified nearly to homogeneity by a single passage through the column. These results suggest that pyran-Sepharose is an effective affinity column that is potentially adaptable as part of a general purification procedure for viral DNA polymerases.

Animals↗
PubMed1971

Mouse Resistance Against Foot-and-Mouth Disease Virus Induced by Injections of Pyran.

Mouse resistance to foot-and-mouth disease virus (FMDV) was induced by intraperitoneal injections of pyran copolymer. A biphasic pattern of protection occurred with greatest resistance 4 and 48 hr after injection of this polyanion. Viremia was not detectable in pretreated mice challenge-exposed with FMDV. Incubation of virus with pyran did not alter viral infectivity in mice or tissue culture. Serum interferon was demonstrated 1 and 2 days after pyran administration.

Journal Article↗
PubMed1982

[Chemical and pharmacological research on pyran derivatives. XV. Phenyl-substituted 2-(dialkylamino)chromones].

Some 2-(dialkylamino)chromones phenyl substituted in position 6 or 7 or 8 were synthesized by reaction of N,N-dialkylethoxycarbonylacetamides with 4- or 3- or 2-biphenylol, respectively, in the presence of phosphorus oxychloride. The pharmacological activity of these compounds was then evaluated and compared with that shown by naphthopyran derivatives of structures (I), (II), and (III). With this same purpose also 6- and 8-benzyl derivatives of 2-(dialkylamino)chromones were prepared by using in the reaction 4- or 2-benzylphenol. Pharmacological screening showed that 6-phenyl substituted 2-(dialkylamino)chromones maintained the antireserpine and antimetrazole acti-activities which were possessed by the 1H-naphtho[2,1-b]pyran derivatives (I) and the 4H-naphtho[2,3-b]pyran derivatives (II), whereas 7-phenyl substituted compounds were devoid of any activity. 8-Phenyl substituted 2-(dialkylamino)chromones maintained to some extent the antiamphetamine activity which was clearly shown by the 4H-naphtho[1,2-]pyran derivatives (III). Furthermore, the compounds bearing the benzyl substituent both in the 6 or 8 position showed only antimetrazole activity.

Animals↗
PubMed1979

Augmentation of natural killer activity by pyran copolymer in mice.

Treatment of older mice with pyran copolymer, a known interferon-inducer, was found to result in a rapid boosting of cell-mediated cytolytic activity against YAC-1 tumor target cells. The effector cells were characterized as being non-adherent and were presumed to be natural killer (NK) cells. Augmentation occurred in various lymphoid organs and was detectable 2-3 days after drug treatment. Differences in the levels of boosted activity among the lymphoid organs resulted when the route of administration was varied. The degree of augmentation was largely independent of the dose of pyran, but did vary among different strains of mice. Augmentation, moreover, was followed by a rapid decline by 5-7 days.

Adjuvants, Immunologic↗