Showing papers on "Pyran published in 1999"
TL;DR: Optimisation of novel cis- and trans-4-(substituted-amido)benzopyran-3-ol derivatives has led to the identification of SB-220453 20 with an in vivo pre-clinical CNS profile predictive of potential antimigraine activity.
51 citations
TL;DR: Pyran ring formation in the biosynthesis of actinorhodin in Streptomyces coelicolor A3 was studied using the act cluster deficient strain, CH999, carrying pRM5-based plasmids harbouring combinations of the actVI genes, suggesting that the act VI-ORF1 product is a reductase determining the C-3 stereochemical centre.
45 citations
TL;DR: Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate (2) was prepared from methyl N-(bensyloxy carbonyl)-glycinate (1) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-amino compounds 7, 8, 20, 36, 38 and 53-57 in yields better than 80% as discussed by the authors.
38 citations
TL;DR: In this article, a palladium catalyzed allylic substitution was used to convert pure 5-acetoxy-2(5H)-furanone and 6-acetoxyl-2H-pyran-3(6H)-one into 5-alkoxy-5H-furanones.
38 citations
TL;DR: The chemical modification of compound 10b led to the discovery that N, N-dipropyl-2- [4-methoxy-3-(2-phenylethoxyl)phenyl]ethylamine hydrochloride 10g, the best compound among arylalkoxyphenylalkylamine derivatives 3, had a high and selective affinity for sigma receptor and had a potent activity in an animal model when the drug was given orally.
Abstract: σ Receptor antagonists may be effective antipsychotic drugs that do not induce motor side effects caused by ingestion of classical drugs such as haloperidol. We obtained evidence that 1-(2-dipropylaminoethyl)-4-methoxy-6H-dibenzo[b,d]pyran hydrochloride 2a had selective affinity for σ receptor over dopamine D2 receptor. This compound was designed to eliminate two bonds of apomorphine 1 to produce structural flexibility for the nitrogen atom and to bridge two benzene rings with a −CH2O− bond to maintain the planar structure. In light of the evidence, N,N-dipropyl-2-(4-methoxy-3-benzyloxylphenyl)ethylamine hydrochloride 10b was designed. Since compound 10b had eliminated a biphenyl bond of 6H-dibenzo[b,d]pyran derivative 2a, it might be more released from the rigid structure of apomorphine 1 than compound 2a. The chemical modification of compound 10b led to the discovery that N,N-dipropyl-2- [4-methoxy-3-(2-phenylethoxyl)phenyl]ethylamine hydrochloride 10g (NE- 100), the best compound among arylalkoxyphenyl...
36 citations
TL;DR: A series of novel cationic merocyanine dyes were prepared by condensation of 1,2,3,3-tetramethylindolium derivatives and 3-formyl-4H-1-benzothiopyran or -benzopyran derivatives, and their photochromic properties were investigated.
Abstract: A series of novel cationic merocyanine dyes were prepared by condensation of 1,2,3,3-tetramethylindolium derivatives and 3-formyl-4H-1-benzothiopyran or -benzopyran derivatives, and their photochromic properties were investigated, especially focusing on the substituent effect in the indolium moiety. These dyes were converted into the spiropyran (SP) form so as to be colorless by irradiation with visible light, although, left under darkness, the colored merocyanine (MC) form was reproduced. The thermal coloration was affected by two factors: the substituent in the indolium moiety and the counter anion. An electron-donating substituent such as a methoxy group at the 5 position effectively retarded the thermal coloration, whereas an electron-withdrawing group such as a nitro group accelerated it. These substituent effects afforded good linearity for the Hammett rule with para σ parameters, indicating that decrease of the electron density in the indoline moiety of the SP form facilitated heterolytic cleavage of the bond between the spiro carbon and the oxygen of the pyran ring.
34 citations
TL;DR: In this paper, the synthesis and properties of furazan derivatives fused with pyridine, pyran, thiopyran and thiepine rings are surveyed and described systematically.
Abstract: The data on the synthesis and properties of furazan derivatives fused with pyridine, pyran, thiopyran, azepine and thiepine rings are surveyed and described systematically. The bibliography includes 85 references.
31 citations
Patent•
08 Jul 1999TL;DR: The photochromic compounds of the invention correspond to the formula: in which Th 2 represents a bithienyl group in one of the positions 5 to 10 of the naphthenic ring system system, R 1 denotes a bitienyl or trithieny group and R 2 denotes a naphthyl, thienyl, furyl, pyrrolyl or N-alkylpyrrolynl group as mentioned in this paper.
Abstract: The photochromic compounds of the invention correspond to the formula: in which Th 2 represents a bithienyl group in one of the positions 5 to 10 of the naphthenic ring system system, R 1 denotes a bithienyl or trithienyl group and R 2 denotes a bithienyl, trithienyl, aryl, naphthyl, thienyl, furyl, pyrrolyl or N-alkylpyrrolyl group.
31 citations
TL;DR: The thermal cyclization of non-conjugated aromatic enetetrayne (4) led to the final products (2 and 10) affording 5 H-12-hydroxybenzo[d]fluoreno[3,2-b]pyran radical (C) and arylcarbene (D) intermediates.
30 citations
TL;DR: An effcient and highly diastereoselective 12-step synthesis of the C(36)-C(45) subunit (2a ) of spongistatin 1 is described in this paper.
29 citations
Patent•
22 Jul 1999
TL;DR: In this article, the authors introduced photochromic plastic objects comprising a plastic material and at least two pyran derivatives introduced into said plastic material, which are characterised by a long life, a good lightening speed, a lack of yellowing and a neutral colour effect.
Abstract: The invention relates to photochromic plastic objects comprising a plastic material and at least two photochromic pyran derivatives introduced into said plastic material. Each pyran derivative has an aryl radical which is bonded with the carbon atom situated next to the pyran-oxygen atom and which is substituted with at least one group containing at least one nitrogen atom. The longest wave absorption maximum of the light-stimulated form of one pyran derivative is above 550 nm and the longest wave absorption maximum of the light-stimulated form of the other pyran derivative is below 550 nm. The shorter wave-absorbing pyran derivative is selected from 3[H]-naphtho[2,1-b]pyrans and the longer wave-absorbing pyran derivative is selected from indeno[2,1-f]-naphtho[1,2-b]pyrans or spiro-9-fluorenol[1,2-b]pyrans. The invention also relates to the use of the inventive photochromic plastic objects, which are characterised in particular by a long life, a good lightening speed, a lack of yellowing and a neutral colour effect. Stabilisers and similar need only be used in small quantities or not at all in the inventive plastic objects.
TL;DR: In this article, the simple γ-pyranones 4, 5, and 6 undergo 4π+2π cycloaddition reactions with Danishefsky's diene 8 and azomethine ylides 12, 16, and 25 to give a range of cycloadducts.
Abstract: The simple γ-pyranones 4, 5, and 6 undergo 4π + 2π cycloaddition reactions with Danishefsky’s diene 8 and azomethine ylides 12, 16, and 25 to give a range of cycloadducts. The position of the electron-withdrawing group is the decisive factor in these reactions, with the 2-substituted derivatives 5 and 6 being less reactive than the 3-substituted γ-pyranone 4. The esters, 4 and 5, react via addition across the 2,3-CC bond of the pyranone ring, whilst the aldehyde 6 reacts via addition across the CO of the carbaldehyde group.
TL;DR: In this paper, the synthesis of bipyrazoles and pyrazoloisoxazoles from 4 is reported, which is the state-of-the-art result.
TL;DR: The title compounds are accessible in high yields and enanti-lectivities by a five-step sequence involving in the key-step asymmetric aldol condensations of masked acetoacetic esters to 3-formyl furan as mentioned in this paper.
Abstract: The title compounds are accessible in high yields and enantioselectivities by a five-step sequence involving in the key-step asymmetric aldol condensations of masked acetoacetic esters to 3-formyl furan.
TL;DR: In this article, an enantioselective synthesis of the trans-syn-trans fused AB cyclic ether rings of brevetoxin natural products was demonstrated using a cyclic pyran template.
TL;DR: Chiral nonracemic pyranocyclohexanes were obtained from a single 1,2-isopropylidene-3-O-cyclohexenyl carbohydrate aldehyde via intramolecular nitrile oxide cycloaddition, and were converted to 2-(2′-tetrahydrofuryl)pyran 28, which incorporated the lasalocid skeleton, and the related oxepane derivative 32 respectively, through modification of the furanoside ring by applying 2-Oallyl carbohydrate nit
TL;DR: In this article, the highly reactive 1:1 intermediate produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates is trapped by dialkyly 2-bromomalonates.
Abstract: The highly reactive 1:1 intermediate produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates is trapped by dialkyl 2-bromomalonates to yield the title compounds in fairly high yields.
TL;DR: A new γ-pyranotropane, darlingine Noxide, was isolated from the bark and leaves of Darlingia darlingiana, along with the known compound darlingine as mentioned in this paper, which indicated that the N-methyl groups of both alkaloids were orientated towards the pyran ring.
TL;DR: The researches of as mentioned in this paper on the synthesis of α α α-dicarbonyl-containing dienes with various structures and study of their valence isomerization to 2H-pyrans1H by an13C NMR, UV, and IR spectroscopy and flash photolysis are reviewed.
Abstract: The researches of the author and her colleagues on the synthesis of α α-dicarbonyl-containing dienes with various structures and study of their valence isomerization to 2H-pyrans1H by an13C NMR, UV, and IR spectroscopy and flash photolysis are reviewed.
TL;DR: In this paper, 2 H -pyran-2-ones with the defined (E )-structure of a α,β-didehydroamino acid unit were used as synthons for a series of configurationally stable ( E )- α, β -didehroamine derivatives containing a benzoyl protected amino function and a pyrazolyl residue.
TL;DR: One-pot reactions of 1,3-cyclohexanedione and 5,5-dimethyl-1,3 cyclohexenedione with 2-(3-methyl-2-butenyloxy)-benzaldehyde and 2-(1,2)-naphthaldehyde resulted in Diels-Alder cycloadducts as mentioned in this paper.
Abstract: The reaction of benzoylacetonitrile, methyl cyanoacetate, and ethyl benzoylacetate with 2-allyloxy- and 2-(3-methyl-2-butenyloxy)-benzaldehyde as well as 2-(3-methyl-2-butenyloxy)-1-naphthaldehyde afforded the corresponding Knoevenagel condensation products. Some of those underwent spontaneous intramolecular cycloaddition to give cis-fused 2H-pyran derivatives as major products. One-pot reactions of 1,3-cyclohexanedione and 5,5-dimethyl-1,3-cyclohexanedione with 2-(3-methyl-2-butenyloxy)-benzaldehyde and 2-(3-methyl-2-butenyloxy)-1-naphthaldehyde resulted in Diels-Alder cycloadducts.
TL;DR: In this article, the development of an approach directed at the total synthesis of the complex cytotoxic marine macrodiolide swinholide is described, which is composed of a trisubstituted pyran moiety with a contrathermodynamic anti arrangement of the C2 and C6 pyrans substituents (swinholides C27 and C31) which is joined by an ethano linker to an acyclic array containing five contiguous stereocenters.
Abstract: The development of an approach directed at the total synthesis of the complex cytotoxic marine macrodiolide swinholide is described. The present study focuses on the development of a synthetic route for the preparation of the C19−C35 segment of the structure, which is composed of a trisubstituted pyran moiety with a contrathermodynamic anti arrangement of the C2 and C6 pyran substituents (swinholide C27 and C31) which is joined by an ethano linker to an acyclic array containing five contiguous stereocenters. The pyran subunit was constructed using a stereoselective allylation of a β-alkoxy aldehyde with 1,3-asymmetric induction and a second stereoselective allylation to prepare the C-glycosidic type of linkage. Use of the Hafner−Duthaler reagent was investigated as a potential means of constructing the anti vicinal hydroxyl−methyl relationships found in the C19−C24 segment but was found not to be practical in this instance. The Evans bis propionate methodology was used to introduce a four-carbon unit, and...
TL;DR: A bis-fused π-electron donor incorporating a pyran-4-ylidene moiety, 2-(1,3-dithiol-2-ylidsene)-5-(pyran 4-idene)-1, 3,4,6-tetrathiapentalene (PDT−TTP, 1a), and its derivatives (1b−d) have been synthesized as mentioned in this paper.
Abstract: A bis-fused π-electron donor incorporating a pyran-4-ylidene moiety, 2-(1,3-dithiol-2-ylidene)-5-(pyran-4-ylidene)-1,3,4,6-tetrathiapentalene (PDT−TTP, 1a), and its derivatives (1b−d) have been synthesized. The cyclic voltammograms of PDT−TTPs are composed of three pairs of redox waves. Comparison of the first oxidation potentials (E1) suggests PDT−TTP (+0.42 V vs SCE in benzonitrile) is a weaker donor than TTF (+0.35 V). The present donors have produced a large number of highly conducting (σrt = 100−102 S cm-1) molecular complexes. Among them, conducting salts based on the ET−PDT (1d) are metallic down to liquid helium temperature. The metallic PF6- salt of ET−PDT has a composition of (ET−PDT)4PF6(cn), where cn is 1-chloronaphthalene, in which two crystallographically independent ET−PDT molecules A and B form a face-to-face stack with a four-folded period as A‘ABB‘. In the present salt, the head-to-tail overlap of the unsymmetrical π-electron framework of PDT−TTP prevents an effective intrastack overlap ...
TL;DR: In this article, the dithionite-mediated addition of 1-iodoperfluorooctane to allyl 4,6-di-O-acetyl was used as a fluorinated building block to prepare the nonamphiphilic chiral mesogens 6-8 by “Mitsunobu” etherification and 9 by esterification, and the major product [(4′R) form] was deprotected via 4 to the hexahydrofuro[2,3-b]pyran derivative 5,
TL;DR: In this paper, X-ray diffraction analyses of two compounds are presented, one of which is a cyclophosphorane and the other is a 2.5-trifluoroacetyl.
Abstract: 5-Trifluoroacetyl-3,4-dihydro-2H-pyran react readily with many nucleophiles such as amines and Grignard reagents to give the rign opened products NuCH*CR
1
R
2 (R
1: (CH2)3OH, R
2:CF3CO). The compound with Nu=Et2N is unstable; it rearranges to 1-hydroxyl-1-trifluoromethyl-2-diethylaminomethylene-tetrahydropyran and 2-diethylamino-3-trifluoroacetyl-tetrahydropyran via an intramolecular nucleophilic addition reaction. Hydrazine and hydroxylamine attack the carbonyl carbon of the title compound to form (CH2)3OCH*CC(CF3)*NZ(Z=NH2, OH). In the presence of KOH, however, hydroxylamine hydrochloride reacts additionally to 2-hydroxyl-2-trifluoromethyl-3-cyano-tetrahydropyran. Upon heating with triethylphosphite, the title compound reacts as a heterodiene and gives the corresponding cyclophosphorane. X-Ray diffraction analyses of two compound are presented.
TL;DR: In this article, conditions of the aldolisation reaction in order to increase diastereoselectivity are described, and the 6-substituted 5,6-dihydro-2 H -pyran-2-ones prepared from aminoaldehydes could be interesting protease inhibitors.
Patent•
25 Jan 1999
TL;DR: In this paper, photochromic spirofluorenopyran compounds of formula (I) were defined, in which: R1 = 1-6C alkyl or alkoxy, phenyl, bromine, chlorine or fluorine (group A'), or R1 + R2 and/or R3 + R4 = a benzo or pyrido ring (each optionally substituted with 1 or 2 group A substituents); G = a 5- to 8-membered ring (including the spiro carbon) onto which at least one
Abstract: Photochromic spirofluorenopyran compounds. Photochromic spirofluorenopyrans of formula (I), in which: R1 = 1-6C alkyl or alkoxy, phenyl, bromine, chlorine or fluorine (group A); R2, R3, R4 = H or a group A substituent (group A'), or R1 + R2 and/or R3 + R4 = a benzo or pyrido ring (each optionally substituted with 1 or 2 group A substituents); G = a 5- to 8-membered ring (including the spiro carbon) onto which at least one ring system (group E) is condensed, such systems comprising benzene, naphthalene, phenanthrene, pyridine, quinoline, furan, thiophen, pyrrole, benzofuran, benzothiophen, indole and/or carbazole (all optionally mono- or di-substituted with group(s) A); B, B' = (a) phenyl or naphthyl (each with 0, 1, 2 or 3 Group F substituents), (b) pyridyl, furyl, benzofuranyl, thienyl, benzthienyl or julolidinyl (all with 0, 1 or 2 Group F substituents) or (c) groups of formula (c1) or (c2), or (d) B + B' may form a fluoren-9-ylidene system (with 0, 1 or 2 Group A substituents) or a saturated hydrocarbon system which is 3-12C spiro-monocyclic, 7-12C spiro-bicyclic or 7-12C spiro-tricyclic; F = OH, amino, mono- or di-(1-6C alkyl)-amino, mono- or di-phenyl-amino (with 0, 1 or 2 ring-substituents), piperidinyl, N-substituted piperazinyl, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, indolinyl, morpholinyl, carbazolyl, pyrryl (with 0, 1 or 2 substituents), 1-6C alkyl or alkoxy, Br, Cl or F, in which the substituents on the (hetero)aromatic groups may be 1-6C alkyl or alkoxy, Br, Cl and/or F; Y, Z = O, S, CH, CH2 or NRN; RN = 1-6C alkyl or acyl, phenyl or H; R = OH or a Group A substituent; m = 0, 1 or 2; R6, R7 = H and/or 1-6C alkyl
TL;DR: An asymmetric synthesis of the tricyclic spiroketal subunit of the saponaceolides was described in this article, in which the absolute stereochemistry at C-2′ and C-6′ was established through a conformationally and stereoelectronically controlled cyclization of a dihydroxyketone pyran intermediate.
TL;DR: 5,6-Dihydro-2H-pyran-2-ones are potent inhibitors of HIV-1 protease, which bind to the S1, S2, S1', and S2' pockets and have a unique binding mode with the catalytic aspartyl groups and the flap region of the enzyme.