Showing papers on "Pyran published in 1984"
TL;DR: In this paper, the preparation of dibenzofuran, carbazole, fluorenone, phenanthridone, 6H-dibenzo c,e][l,2]thiazine-5,5-dioxide, benzofurano[2,3b]pyridine derivatives is described, and the cyclisation of 3-benzamido-2-chloropyridine to 6-hydroxybenzoc][1,5]naphthyridne illustrates the regiospecificity of the
193 citations
TL;DR: Of the compounds tested in vitro for inhibition of RNA-dependent DNA polymerase and in mice infected with Rauscher leukemia, all retained good enzyme activity and only the 2-methyl-2-phenyl derivative 10e proved to be about as potent as the 2,2-dimethyl reference compound 10a in prolonging the mean survival time of mice with RaUScher leukemia virus induced leukemia.
Abstract: In order to find a 3,4-dihydro-2H-naphtho[1,2-b]pyran-5,6-dione more potent than the naturally occurring 2,2-dimethyl derivative [beta-lapachone (10a)], we synthesized a series of analogous compounds with modifications at position 2 of the pyran ring or at positions 8 and 9 of the benzene ring. Of the compounds tested in vitro for inhibition of RNA-dependent DNA polymerase and in mice infected with Rauscher leukemia, all retained good enzyme activity. Inhibition of the reverse transcriptase activity of the 2,2-substituted derivatives 10b-e was as strong as 10a. However, only the 2-methyl-2-phenyl derivative 10e proved to be about as potent as the 2,2-dimethyl reference compound 10a in prolonging the mean survival time of mice with Rauscher leukemia virus induced leukemia.
126 citations
TL;DR: Biological testing in five models of pain shows that compound 1 and morphine are equally potent as analgesics and demonstrates that the pyran ring of HHC is not necessary for biological activity.
Abstract: The synthesis and analgesic testing of 3-[4-(1,1-dimethylheptyl)-2-hydroxyphenyl]cyclohexanol (1) are described. Prior (SAR) studies led us to conclude that the pyran ring of 9-nor-9 beta-hydroxyhexahydrocannabinol (HHC) was not necessary for the expression of biological activity in this series of cannabinoids. Analysis of models and the use of molecular mechanics calculations suggested that a simpler compound, such as 1, would possess the biological activity of HHC. Compound 1 was prepared in nine steps from [3-(benzyloxy)phenyl]acetonitrile (2). Biological testing in five models of pain shows that compound 1 and morphine are equally potent as analgesics and demonstrates that the pyran ring of HHC is not necessary for biological activity. Further simplification of 1 was pursued by the synthesis of 4-[4-(1,1-dimethylheptyl)-2-hydroxyphenyl]-2-pentanol (17), but this derivative exhibits significantly reduced analgesic activity.
95 citations
Abstract: The reaction of various types of acetyl compounds with a ketene dithioacetal, methyl 2-cyano-3, 3-bis (methylthio) acrylate, in the presence of potassium hydroxide gave the corresponding 6-aryl-and 6-styryl-3-cyano-4-methylthio-2H-pyran-2-one derivatives. The methylthio group on the pyrone ring reacted readily with nucleophiles such as amines, active methylene compounds and methoxy anion to yield the corresponding displacement products in good yields.
67 citations
TL;DR: In this paper, simple benzopyrans with a fused γ-lactone unit were prepared from an o-disubstituted arene by direct intramolecular alkoxycarbonylation/lactonization promoted by palladium diacetate; the process gives high yields and moderate stereoselectivity, favoring the cis lactone over trans by a factor of 5:1.
59 citations
TL;DR: A new natural product, 3,4,8,9,10-pentahydroxy-dibenzo-[b,d]pyran-6-one was isolated from the flowers of Tamarix nilotica which also contains the known compound ellagic acid as discussed by the authors.
41 citations
TL;DR: The high pressure cycloaddition of 1:2,3:4-di-0-isopropylidene- α-D-galactopyranos-6-ulose (3) to 1-methoxybuta-1,3-diene (1) afforded diastereoisomerically pure cycloadduct 4 whose absolute configuration was determined as mentioned in this paper.
29 citations
TL;DR: In this article, the same base and solvent, but in air, afforded a mixture comprising its cis-epimer (42), together with the two possible 4-hydroxy derivatives, namely (35) and (38).
Abstract: Treatment of 3-(1-hydroxyethyl)-1,4,5,7-tetrarmethoxy-2-prop-2-enylnaphthalene (33) with potassium t-butoxide in dimethylformamide under nitrogen for a short time gave a high yield of trans-3,4-dihydro-5,7,9,10-tetramethoxy-1,3-dimethyl-1H-naphtho[2,3-c]pyran (41). This compound, with the same base and solvent, but in air, afforded a mixture comprising its cis-epimer (42), together with the two possible 4-hydroxy derivatives, namely (35) and (38). Silver(II) oxide oxidation of compounds (35), (38), (41), and (42) gave, respectively, the dimethyl ethers of quinone A, quinone A′, and deoxyquinone A, and also 7-methoxyeleutherin.
22 citations
TL;DR: The reaction of substituted cinnamonitrile derivatives with cyanoacetanilide and with ethyl acetoacetate produced several new polyfunctional pyridine and pyran derivatives.
15 citations
13 citations
Patent•
01 Mar 1984TL;DR: Phenylthiomethyl-6-hydroxy-2,3-dihydro-benzopyran-7-yl formaldehyde or analog thereof with a substituted thiophenol was found to be potent anti-inflammatory agents as mentioned in this paper.
Abstract: Phenylthiomethyl-6-hydroxy-2,3-dihydrobenzopyran and analogs thereof were prepared from an appropriate (6-hydroxy-2,3-dihydro-benzopyran-7-yl) formaldehyde or analog thereof with a substituted thiophenol. These compounds were found to be potent anti-inflammatory agents.
Patent•
15 Jun 1984TL;DR: In this paper, the authors defined a class of compounds of the formula STR1 with the proviso that both X and Y are not a single bond, and Z is H or alkyl.
Abstract: Compounds of the formula ##STR1## wherein X is a single bond or --C(CH 3 ) 2 ; Y is a single bond or --CH 2 -with the proviso that both X and Y are not a single bond, and Z is H or alkyl; each R is H, hydroxy, oxo, methylene, alkyl or alkoxy, or one pair of adjacent R groups form a carbon-carbon bond; and R 1 is H or alkyl, are useful as herbicides or plant growth regulators.
TL;DR: In this paper, β-unsaturated carbonyl compounds and phosphacumulene ylides undergo a [4+2]-cycloaddition with formation of pyran-substituted phosphoranes.
TL;DR: In this paper, the synthesis of 6-alkenyl-5-ethoxycarbonyl-2,3-dihydro-4H-pyran-4-one derivatives by acylation of γ,β-unsaturated β-keto esters or by diacylation of ethyl hydrogen malonate with α,βunsaturated acyl chlorides are described.
Patent•
22 Mar 1984
TL;DR: In this paper, it was shown that the lactam group is trans to the OR5 group, having anti-hypertensive activity, and the carbon atom to which they are attached is C3-6 spiroalkyl.
Abstract: Compounds of the formula (I): ##STR1## wherein: one of R1 and R2 is hydrogen and the other is C1-6 alkyl-thiocarbonyl, C1-6 alkoxy thiocarbonyl, C1-6 alkyl-thiocarbonyloxy, 1-mercapto C2-7 alkyl or formyl; one of R3 and R4 is hydrogen or C1-4 alkyl and the other is C1-4 alkyl, or R3 and R4 together with the carbon atom to which they are attached are C3-6 spiroalkyl; R5 is hydrogen, C1-3 alkyl or C1-8 acyl; and n is 1 or 2; the lactam group being trans to the OR5 group, having anti-hypertensive activity.
TL;DR: In this article, the effects of 5-acyl substituents on the tautomerism of pyran-2,4-diones are revealed by comparison of the u.m.v., 1H, and 13C n.r. spectral properties.
Abstract: The effects of 5-acyl substituents on the tautomerism of pyran-2,4-diones are revealed by comparison of the u.v.,i.r., 1H, and 13C n.m.r. spectral properties of 5-acetyl-6-methyl-,5-acetyl-6-phenyl-,5-benzoyl-6-methyl-, and 3,5-diacetyl-6-methyl-pyran-2,4-diones (3)–(6), with those of 6-methyl-(1) and 3-acetyl-6-methyl-pyran-2,4-done (2). The differences in the behaviour of the 5-acyl and 3-acyl derivatives towards primary amines are also discussed. Compound (6) reacts with aniline to form 5-acetyl-2,6-dimethyl-1-phenyl-4-oxopyridine-3-carboxylic acid (7).
Journal Article•
TL;DR: The mobilizing effect of pyran copolymer appears promising enough to warrant further exploration of blood as a source of hemopoietic stem cells for transplantation purposes.
TL;DR: In this paper, the structure of the products were assigned and confirmed on the basis of their elemental analysis and the electronic absorption, infrared and nmr spectra, respectively, based on their spectral properties.
Patent•
01 Aug 1984
TL;DR: In this article, it was shown that compounds of formula have central nervous system activity and are useful intermediates and can be obtained by reacting a compound of formula with a reactive derivative thereof.
Abstract: Compounds of formula (I> wherein each of R1 and R2 independently is hydrogen or C1-C10 alkyl; or R1 and R2, taken together, form a C5-C7 cycloalkyl ring; R3 is hydrogen, C1-C10 alkyl or phenyl; R4 is hydrogen or C1-C6 alkyl; R5 is -OR9 or -SR9, wherein R9 is hydrogen or C1-C6 alkyl; each of R6, R7 and R8 independently is hydrogen, C1-C12 alkyl or phenyl; and their salts with bases; may be prepared by: a) reacting a compound of formula (II> with a compound of formula (III> or a reactive derivative thereof, so obtaining a compound of formula (IV> and, if desired, alkylating a compound of formula (IV), so obtaining a compound of formula (V> wherein R'4 is C1-C6 alkyl, and then aromatizing a compound of formula (IV) or (V) and, if desired, converting the compound of formula (I) thus obtained into a salt thereof with a base. The compounds of formula (I) have central nervous system activity and are useful intermediates.
TL;DR: The protection of pyran copolymer pretreated mice from infection with C. neoformans, but the absence of significant killing of encapsulated yeast in vitro suggest a complex mechanism of host defense which may involve an activation of the reticuloendothelial system by pyra-copolymer.
Abstract: Synthetic polyanions have been shown to alter host resistance to infection. The anticryptococcal effect of pyran copolymer was assessed in vivo and in vitro. Pretreatment with pyran copolymer significantly extended mean survival in mice lethally infected with Cryptococcus neoformans when compared to untreated animals (p less than 0.01). The anticryptococcal effect of peritoneal exudate cells (PEC) elicited by 10% thioglycollate or pyran copolymer (25 mg/kg) was assessed in vitro. Initial percent phagocytosis of both encapsulated and non-encapsulated isolates of C. neoformans was greatest in the pyran elicited PEC. Significant killing of C. neoformans in vitro was observed only in pyran-activated PEC cultures combined with non-encapsulated cells of C. neoformans, although pyran PEC did inhibit initial growth of phagocytized encapsulated yeast cells. The protection of pyran copolymer pretreated mice from infection with C. neoformans, but the absence of significant killing of encapsulated yeast in vitro suggest a complex mechanism of host defense which may involve an activation of the reticuloendothelial system by pyran copolymer.
Journal Article•
TL;DR: This paper describes the synthesis of 6-carboxy derivatives of 6H-dibenzo[b,d]pyran, which showed very high hypolipidemic activity being 12 times more potent than clofibrate in reducing plasma cholesterol concentration in the hypercholesterolemic rat.
Abstract: This paper describes the synthesis of 6-carboxy derivatives of 6H-dibenzo[b,d]pyran. These compounds are among the most rigid structures related to clofibrate ever synthesized, which means they have very few possible conformations of relative stability compared with the many for clofibrate. Compound 6H-2-chloro-6-methyl-dibenzo[b,d]pyran-6-carboxylic acid 3g showed very high hypolipidemic activity being 12 times more potent than clofibrate in reducing plasma cholesterol concentration in the hypercholesterolemic rat and 11 times more potent in reducing plasma triglyceride concentration in the normolipemic rat.
TL;DR: Etude par la methode MNDO de la structure moleculaire et electronique du 4H-Pyranone-4 et de ses analogues soufres.
Abstract: Etude par la methode MNDO de la structure moleculaire et electronique du 4H-Pyranone-4 et de ses analogues soufres. Calcul des densites de charges
TL;DR: In this article, the loss of CH3˙ from the molecular ions of cyclohexene oxide and 5,6-dihydro-4-methyl-2H-pyran has been investigated.
Abstract: The loss of CH3˙ from the molecular ions of cyclohexene oxide and 5,6-dihydro-4-methyl-2H-pyran has been investigated. On the basis of metastable peak shape analysis, collision-induced dissociation/mass-analysed ion kinetic energy spectra and thermochemical data it is concluded that the same [C5H7O]+ ion is formed in both cases.
TL;DR: A series of 1-substituted 3-alkenyl-4-oxo-6,7-dihydro-1H-pyrano[4,3-c]pyrazoles was prepared by reaction of arylhydrazines or benzylhydrazine with 4,5-dioxo-2,3,7,8-tetrahydro -4H,5H-polymorphic pyran derivatives as mentioned in this paper.
TL;DR: In this paper, the relative configurations of the threo and erythro isomers of 2-nitro-1-phenylpropane-1,3-diol (the starting materials) were determined by 1H and 13C NMR spectroscopy.
Abstract: Nitro-substituted 1,3-dioxanes and pyrans with potential biological activity were synthesized. The relative configurations of the threo and erythro isomers of 2-nitro-1-phenylpropane-1,3-diol (the starting materials) and of 5-nitro-2,4-diphenyl-1,3-dioxane, the products formed with benzaldehyde, were determined by 1H and 13C NMR spectroscopy. Cinnamaldehyde and nitroethanol give a homologue of nitrophenylpropanediol, which exists as a mixture of two diastereomeric cyclic hemiacetals. After dissolving in CDCl3, the ratio of these components changes from approximately 10:1 to 3:2 in a few days. The ethyl acetal of the hemiacetal is stereohomogeneous, and the ethoxy group is axial to the pyran ring owing to the anomeric effect. This configuration was proved by two-dimensional NMR measurement, permitting separate observation of the originally overlapping multiplets and direct reading of the H,H coupling constants.
Patent•
18 Oct 1984
TL;DR: In this paper, the tobacco beetle Lasioderma seriicorne F. of EP0053756A 2,3-dihydropyran of the general formula was considered.
Abstract: of EP0053756A 2,3-dihydropyran of the general formula: wherein R1, R2, R3 and R4 are hydrogen or alkyl groups having from 1 to 4 carbon atoms; and where at least two of the groups R1, R2, R3 and R4 are said alkyl groups; including all optical isomers thereof is useful in combatting insects, particularly the tobacco beetle Lasioderma seriicorne F.