Showing papers on "Pyran published in 1976"

Zur Cyclisierung von Dehydrolinalylacetat in Gegenwart von Zinkchlorid

Abstract: ZnCl2-catalysed cyclisation of dehydrolinalyl acetate. Dehydrolinalyl acetate has been converted to carvenone (5), the corresponding enol acetate 2-acetoxy-p-mentha-1,3-diene (6), and to 2-acetoxy-2-carene (7). The acetate of the pyran 8 is also formed. The same intermediate is postulated in the formation of both 6 and 7.

A convenient preparation of maltol, ethylmaltol, and pyromeconic acid from 2-alkyl-6-methoxy-2h-pyran-3(6h)-ones

Abstract: The efficient synthesis of 2-alkyl-3-hydroxy-4H-pyran-4-ones, e. g., pyromeconic acid (6a), maltol (6b), and ethyl maltol (6c), from 2-alkyl-4,5-epoxy-6-methoxytetrahydropyran-3-ones 5 by acid-catalyzed rearrangement is described. The key precursors 5 were obtained by epoxidation of 2-alkyl-6-methoxy-2H-pyran-3(6H)-ones 4, which were synthesized by three steps starting from furfuryl alcohols 1.

Specific potentiation of L1210 vaccine by pyran copolymer.

Abstract: Pyran copolymer (NSC 46015) was found to potentiate strongly the immune response of C57BL/6J X DBA/2 F1 mice to 10(4) live L1210 tumor cells following suboptimal vaccination with 10(7) radiation-inactivated L1210 cells. Optimal immunity to challenge was produced by concomitant i.p administration of pyran and L1210 vaccine, and activity was dependent upon both pyran and vaccine dosages. In addition, this immunopotentiation seemed to be related to the intrinsic viscosity of different pyran preparations tested, although all the pyran compounds had significant activity. Furthermore, the increased immunity of subsequent live tumor challenge appeared to be specific for the vaccinating cell type.

Syntheses of the naturally occurring naphtho[2,3-b]pyran-5,10-quinones α-caryopterone, dihydro-α-caryopterone, and O-methyldihydro-α-caryopterone

Abstract: The title compounds have been prepared by appropriate alkylation of 3-hydroxy-5-methoxy-1,4-napthoquinone, obtained from the adduct (6) derived by addition of 1-methoxycyclohexa-1,3-diene (4) to 2-methoxy-1,4-benzoquinone (5).

Enhancement of a tumor allograft in BALB/c x DBA/2 F1 mice by pyran copolymer.

Abstract: Pyran copolymer (NSC 46015) was evaluated with respect to its effect on the rejection of a murine leukemic allograft by BALB/c x DBA/2 F1 (CD2F1) mice. Significant prolongation of allograft survival with production of progressively growing lethal tumors was found following pyran administration. This phenomenon occurred at nontoxic doses of the drug and appeared to be closely related to the timing of pyran injection. Nonspecifically stimulated lymphocyte blast transformation by concanavalin A was not impaired by pyran when lymphocytes were exposed in vitro to the drug. The mechanism of tumor allograft enhancement remains obscure but may be related to allograft size at the time of pyran administration.

Process for converting 2,7-dihydroxy-5-isopropylidene-9-substituted-2,6-methano-3,4,5,6-tetrahydro-2H-1-benzoxocin to trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo(b,d)pyran-9-one

Abstract: Reaction of an aluminum halide with a 2,7-dihydroxy-5-isopropylidene-9-substituted-2,6-methano-3,4,5,6-tetrahydro-2H-1-benzoxocin in an organic solvent effects cleavage of the pyran ring system with concomitant recyclization to provide exclusively a trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo[b,d]pyran-9-one.

Crystal structures of phenacylkojate (2-(hydroxymethyl)-5-phenacyloxy-4H-pyran-4-one) and its complex with sodium chloride: bis(phenacylkojate)sodium chloride

Abstract: The structures of the title compounds have been determined by three dimensional X-ray crystal structure analysis.Crystals of anhydrous phenacylkojate are monoclinic, space group P21/c, with unit ce...

Polyanion induced nuclear swelling and microsphere formation

Abstract: Natural and synthetic polyanions are known to have a broad spectrum of physiologic and pharmacologic properties. Some polyanions can activate in vitro nucleic acid biosynthesis in isolated nuclei, and induce varying degrees of nuclear swelling and chromatin decondensation. This in vitro phenomenon has an in vivo analog in gene activation. Pyran, a copolymer of divinyl ether and maleic anhydride, is a particularly interesting polyanion because of its antitumor, antiviral, and immunostimulating activities. Although the mechanism of its activities is unknown, its polyanionic character suggests that it may be considered as a model “gene regulator.” The present investigation focused upon the interaction of Pyran with nuclei isolated from normal mouse spleens. Small angle light scattering was used to monitor nuclear swelling, and the conditions required to demonstrate swelling were established. It was shown that Pyran-induced nuclear swelling results from the ability of this polyanion to form a complex with Mg 2+ . It was also shown by nephelometric titration methods and small angle light scattering that the interaction of Pyran and Mg 2+ resulted in the precipitation of “microspheres.” These results have led to a working hypothesis relating to the possible molecular mechanism of the pharmacologic action of Pyran copolymer.

Use of substituted pyrans as deodorant chemicals

Abstract: Substituted pyran compounds as exemplified by 2,5-dimethyl-3,4-dihydro-2H-pyran-2-carbinol are used as chemically active deodorizing agents in admixture with substrates such as gelatinous substances, powders, sprays, soaps, etc.

The 2-pyridone–pyran-2-imine and pyridine-2-thione-thiopyran-2-imine systems; interconversions and characterisation of isomeric species

Abstract: Whereas 2-arylamino-4,6-diphenylpyrylium chlorides are readily converted into 2-pyridones, the corresponding 2-arylamino-4,6-diphenylthiopyryliuni iodides do not give pyridine-2-thiones; mass spectra unambiguously distinguish between isomeric structures in these series.

Role of Divalent Ion Complex Formation in Pyran—Inhibition of Nucleic Acid Biosynthesis

Abstract: The degree of inhibition of mammalian DNA-dependent RNA polymerases I and II and Moloney leukemia virus RNA-dependent DNA polymerase by pyran copolymer was dependent on the concentration of the divalent cation cofactor in the reaction mixture. Inhibition was completely blocked by an excess of divalent cations. It was concluded that pyran inhibited these enzymes by complexing with the essential divalent cation cofactor.

Preparation of cis-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo[b,d]pyran-9-ones and intermediates therefor

Abstract: Reaction of a 5-substituted resorcinol with a ketal of 4-(1-hydroxy-1-methylethyl)-3-cyclohexen-1-one in the presence of a suitable catalyst effects condensation to provide substantially exclusively a cis-1-hydroxy-3-substituted-6-6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo[b,d]pyran-9-one

Process for preparing 3-oxy-4H-pyran-4-one derivatives

Abstract: A process for preparing a 3-oxy-4H-pyran-4-one derivative which comprises the steps of: 1. epoxidizing a 3-oxo-3,6-dihydro-2H-pyran derivative with a peroxide to obtain a 4,5-epoxy-3-oxotetrahydropyran derivative, and 2. heating the 4,5-epoxy-3-oxotetrahydropyran derivative.

Pharmaceutical compositions comprising substituted 3-cinnamoyl-2H-pyran-2,6(3H)-diones

Abstract: Pharmaceutical compositions comprising a substituted 3-cinnamoyl-2H-pyran-2,6(3H)-dione and methods of inhibiting the antigen-antibody reaction by administering said compositions. Certain of the 3-cinnamoyl-2H-pyran-2,6(3H)-diones are novel compounds per se.

Substituted 2H-pyran-2,6 (3H)-dione derivatives useful in treatment of allergic reactions

Abstract: Substituted 2H-pyran-2,6(3H)-dione derivatives useful in the treatment of allergic conditions are prepared by reaction of 3,5-diacetyl-4,6-dihydroxy-2H-pyran-2-one with an appropriate aniline.

The cyclic acetals from 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylalkanols

Abstract: The reaction of 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylmethanol with sodium ethoxide to afford the cyclic acetal 5-endo,6,7,7,8-pentachloro-4-exo-ethoxy-3-oxatricyclo[4.2.1.04,8]nonane is found to involve the intermediacy of 1,4,5,7,7-pentachloro-6-ethoxynorborn-5-en-2-endo-ylmethanol and 4-exo, 5-endo, 6,7,7,8-hexachloro-3-oxatricyclo[4.2.1.04,8]nonane. 6-endo,7,8,8,9-Pentachloro-5-exo-ethoxy- and methoxy-4-oxatricyclo[5.2.1.05,9]decane are formed from the reactions of 1,4,5,6,7,7-hexachloronorborn-5-en-2-endo-ylethanol with sodium ethoxide and methoxide, respectively. N.m.r. studies suggested that in these product cyclic acetals the conformation of the pyran ring tends towards a boat rather than a chair form.

Substituted 3-(1-aminoethylidene)-5-cinnamoyl-2H-pyran-2,6(3H)-diones

Abstract: Substituted 3-(1-aminoethylidene)-5-cinnamoyl-2H-pyran-2,6(3H)-diones useful as inhibitors of certain antigen-antibody reactions, particularly in alleviating allergic manifestations such as asthma, are prepared by reaction of a 3-(1-aminoethylidene)-5-acetyl-2H-pyran-2,6(3H)-dione with an appropriately substituted benzaldehyde.

Process for converting cis-hexahydrodibenzo[b,d]pyran-9-ones to trans-hexahydrodibenzo[b,d]-pyran-9-ones

Abstract: Reaction of cis-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo[b,d]pyran-9-ones with an aluminum halide in an unreactive organic solvent effects complete epimerization to provide the corresponding trans-1-hydroxy-3-substituted-6,6-dimethyl-6,6a,7,8,10,10a-hexahydro-9H-dibenzo[b,d]pyran-9-one.

3,8-Bis-basic ethers of 6H-dibenzo[b,d]pyran-6-one

Abstract: Bis-basic ethers of 9-sustituted phenanthrene and related 10-oxa and 10-aza derivatives, their method of preparation and their use as pharmaceutical agents for the prevention and inhibition of viral infections are disclosed.

Spiropyrans based on 5,1 0-dimethyl-4, 9-diazapyrene

Abstract: The corresponding mono- and displropyrans, the cyclic forms of which are more stable than the analogous compounds of the phenanthridine series, were obtained by condensation of mono- and diquaternary salts of 5,10-dimethyl-4,9-diazapyrene with aromatic o-hydroxy aldehydes. Successive opening of the pyran rings of the dispiropyrans occurs in acetic acid solutions, whereas the monospiropyrans, after opening of the pyran ring, are protonated at the nitrogen atom in the 9 position.

A convenient preparation of maltol, ethylmaltol, and pyromeconic acid from 2-alkyl-6-methoxy-2h-pyran-3(6h)-ones

Abstract: The efficient synthesis of 2-alkyl-3-hydroxy-4H-pyran-4-ones, e. g., pyromeconic acid (6a), maltol (6b), and ethyl maltol (6c), from 2-alkyl-4,5-epoxy-6-methoxytetrahydropyran-3-ones 5 by acid-catalyzed rearrangement is described. The key precursors 5 were obtained by epoxidation of 2-alkyl-6-methoxy-2H-pyran-3(6H)-ones 4, which were synthesized by three steps starting from furfuryl alcohols 1.

O-Carboxymethyl-malic acid prodn for detergent compsns - by reacting 5,6-dihydro-2H-pyran-5-carboxylic acid ester with nitric acid

Abstract: O-Carboxymethylmalic acid is produced by reacting 5,6-dihydro-2H-pyran-5-carboxylic acid ester (pref. mbutyl or ethyl ester) with HNO3 (esp. 40-50 degrees C) in the presence of a catalyst (esp. NH4VO3, in an amt. of pref. 1-3 wt. % w.r.t. the starting ester). The starting ester can be produced by Diels-Alder reaction from butadiene and a glyxlic acid ester or its hemiacetal. O-Carboxymethylmalic acid can be used as a builder in detergent compsn. as it forms complexes with agents causing water hardness; it can be decomposed biologically. The method is economic and can be applied in large-scale prodn.

Substituted 2h-pyran-2,6(3h)-dione derivatives, pharmaceutical compositions comprising such derivatives and methods of inhibiting the antigen-antibody reaction

Abstract: Substituted 2H-pyran-2,6(3H)-dione derivatives, pharmaceutical compositions comprising such derivatives and methods of inhibiting the antigen-antibody reaction by administering said compositions. The active ingredients are the products formed by the reaction of acetonedicarboxylic acid with acetic anhydride followed by reaction with an appropriate amine. Certain of the dione derivatives are novel compounds per se.