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Showing papers on "Pyran published in 1987"


Patent
17 Jun 1987
TL;DR: In this article, a blue-coloring pyran compound with a nitrogen-containing substituent in the 2-position of the pyranium ring was described. But the substituents were not specified.
Abstract: Photoreactive plastics lenses are disclosed which are coated or impregnated with an adamantane 2-spiro-benzo or naphthopyran and with a blue coloring photochromic benzo- or naphthopyran having a nitrogen containing substituent in the 2-position in the pyran ring. The lenses darken in sunlight and fade rapidly at ambient temperatures in the dark or in white light which does not contain a U.V. component. The combination of the yellow/orange coloring adamantane 2-spiro pyran compound with the purple/blue coloring pyran gives a desired brown/grey coloration in the sunlight-darkened lens. The invention includes novel blue-coloring pyran compounds in which the nitrogen-containing substituent in the 2-position is a phenyl group having an amino or substituted amino or nitrogen-containing heterocyclic substituent in the ortho- or para-position of the phenyl group. The basic chromene structure and the suffix N will be used to distinguish the blue-coloring pyran compounds having a nitrogen-containing substituent, namely: ##STR1##

101 citations


Journal ArticleDOI
TL;DR: In this paper, a homologue of pheromones of a species in the Hepialidae family was synthesized using (2R)-(+)-2,3-Dihydro-2,6-dimethyl-4H-pyran-4-one.
Abstract: (1987). Synthesis of (2R)-(+)-2,3-Dihydro-2,6-dimethyl-4H-pyran-4-one, a Homologue of Pheromones of a Species in the Hepialidae Family. Agricultural and Biological Chemistry: Vol. 51, No. 7, pp. 2001-2002.

100 citations






Journal ArticleDOI
Gerald E. Stokker1
TL;DR: Arylation of 6-[2-(2,4-dichlorophenyl)ethyl]-5,6-dihydro-2H-pyran-2-one with aryl iodides in the presence of Pd [0] resulted in stereospecific addition followed by a hydrogen abstraction from triethylamine as discussed by the authors.

41 citations


Journal ArticleDOI
TL;DR: Tetrakis(triphenylphosphine)palladium(0) effects the regio- and stereo-selective alkylation of 2-acetoxy-5,6-dihydro-2H-pyrans and 1-S-acetyl-1-thiohex-2-enopyranosides.

41 citations


Journal ArticleDOI
TL;DR: In this article, the reaction of polymeric procyanidins (condensed tannins) with toluene-α-thiol at pH 12.0 and 23 °C gave predominantly one stereoisomer of 1,3-bisbenzylthio-1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxymhenyl) propan-2-ol (10) by stereoselective reaction at C-4 and C-2 of the quinone meth
Abstract: Reaction of polymeric procyanidins (condensed tannins) with toluene-α-thiol at pH 12.0 and 23 °C gave predominantly one stereoisomer of 1,3-bisbenzylthio-1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl) propan-2-ol (10) by stereoselective reaction at C-4 and C-2 of the quinone methide derived from the upper 2,3-cis procyanidin units. Smaller amounts of two isomers of 1-benzylthio-1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-ol (4) were obtained by reaction at the C-2 of catechin obtained from the terminal units. At higher temperatures, (10) loses toluene-α-thiol preferentially from C-1 to give 1-benzylthio-1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-one (11) by a tautomeric rearrangement of the quinone methide via an enol to the ketone. Loss of toluene-α-thiol from (4) gave 1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-one (5) by a similar rearrangement. This compound further rearranges to 1-(3,4-dihydroxyphenyl)-4,6-dihydroxyindan-2-one (6).

33 citations


Journal ArticleDOI
TL;DR: In this paper, a more efficient synthesis of the title compound (12), previously used in the total synthesis of (+)-milbemycin β3(2), is described, which involves a nucleophilic cleavage of the oxirane (33) by the organocuprate derived from metallation of (2R,3S)-2,3-dimethyl-3,4-dihydro-2H-pyran (26).
Abstract: A more efficient synthesis of the title compound (12), previously used in a total synthesis of (+)-milbemycin β3(2), is described. The key step in the sequence involves a nucleophilic cleavage of the oxirane (33) by the organocuprate (28) derived from metallation of (2R,3S)-2,3-dimethyl-3,4-dihydro-2H-pyran (26).

33 citations


Journal ArticleDOI
TL;DR: Cyclization of cis - and trans -2-allylcyclohexanols and cyclohexene-3-yl alcohols with benzene-selenenyl triflate affords corresponding fused tetrahydrofurans and -pyrans as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, 2-Ethoxy-3,4-dihydro-2H-pyran-6-carbonitriles are obtained in high yield by stereospecific endo-mode cyclo-additions of α,β-unsaturated acyl cyanides and ethyl vinyl ether at room temperature.
Abstract: 2-Ethoxy-3,4-dihydro-2H-pyran-6-carbonitriles are obtained in high yield by stereospecific endo-mode cyclo-additions of α,β-unsaturated acyl cyanides and ethyl vinyl ether at room temperature. The nitrile group is converted to some other functionalities.

Journal ArticleDOI
TL;DR: In this paper, 9-hydroxy-dihydrofuro-2,3b-tetrahydropyran is synthesized as a model substance for azadirachtin.

Journal ArticleDOI
Yujin Huang1, Xiyan Lu1
TL;DR: Pyran derivatives can be synthesized by the reaction of 2-methylene propane-1, 3-diol diacetate (1 ) with β-diketones or β-ketoesters in the presence of DBU under palladium(O) catalysis as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, a more efficient synthesis of the title compound (2), previously used in the total synthesis of (+)-milbemycin β3(1), is described. The key step in the sequence involves a nucleophilic cleavage of the oxirane by the organocuprate derived from metallation of (2R,3S)-2,3-dimethyl-3,4-dihydro-2H-pyran (5).
Abstract: A more efficient synthesis of the title compound (2), previously used in a total synthesis of (+)-milbemycin β3(1), is described. The key step in the sequence involves a nucleophilic cleavage of the oxirane (4) by the organocuprate derived from metallation of (2R,3S)-2,3-dimethyl-3,4-dihydro-2H-pyran (5).

Patent
23 Nov 1987
TL;DR: In this article, a method for inhibiting the biosynthesis of cholesterol employing such pharmaceutical compositions is also disclosed, and pharmaceutical compositions containing such compounds, and a method of inhibiting cholesterol employing these pharmaceutical compositions are also disclosed.
Abstract: Certain trans-6-[2-[2-(substituted-phenyl)-3- (or 4-)heteroaryl-5-substituted-1H-pyrrol-1-yl]ethyl]tetrahydro-4-hydroxy-2H-pyran-2-ones and the corresponding lactone-ring-opened acids are potent inhibitors of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG CoA reductase) and are thus useful hypolipidemic or hypocholesterolemic agents. Pharmaceutical compositions containing such compounds, and a method of inhibiting the biosynthesis of cholesterol employing such pharmaceutical compositions are also disclosed.

Journal ArticleDOI
TL;DR: In this paper, simple synthetic routes to 2-cyclopentenone derivatives and 1,3-cycledione from 3-acetoxy-6-acetoxymethyl-2H-pyran-2-one were developed.
Abstract: Simple synthetic routes to 2-cyclopentenone derivatives and 1,3-cyclopentanedione from 3-acetoxy-6-acetoxymethyl-2H-pyran-2-one were developed.

Journal ArticleDOI
TL;DR: In this paper, a facile route to 2-aryl-6-methylthio-4H-pyran-4-ones 4a-f has been developed by base-catalyzed condensation of acylketene dithioacetal 2 with substituted methyl benzoates, followed by subsequent ring closure.
Abstract: A facile route to hitherto unreported 2-aryl-6-methylthio-4H-pyran-4-ones 4a-f has been developed by base-catalyzed condensation of acylketene dithioacetal 2 with substituted methyl benzoates 1a-f followed by subsequent ring closure of resulting α-aroylacylketene dithioacetals 3a-f. Acylketene dithioacetal 2 and the corresponding β-methylthioenone 9 are shown to undergo self-condensation and aromatization in the presence of sodium hydride and methylbenzoate in refluxing xylene to give 2, 6-bis(methylthio)-4-hydroxy-acetophenone (6) and 4-hydroxyacetophenone (10) respectively in good yields. A mechanistic pathway for the formation of 6 and 10 via 3 has been described.

Journal ArticleDOI
TL;DR: In this paper, the 3-methyl, n-butyl, and phenyl derivatives of 3,10b-epidioxy-2,3,4a, 10b-tetrahydro-6-methyl-1H-naphtho[2,1-b]pyran were given.
Abstract: 3,3,6,10b-Tetramethyl-4a, 10b-dihydronaphtho[2,1-e][1,2,4]trioxane and its 3,3-spirocyclic cyclopentane analogue on treatment with an excess of trimethylsilyl trifuloromethanesulphonate for 10 min at 24 °C rearrange to give 2-(2-oxopropyl)-3-methyl-1-benzofuran in high yield; in similar fashion the 3-methyl, n-butyl, and phenyl derivatives of 3,10b-epidioxy-2,3,4a,10b-tetrahydro-6-methyl-1H-naphtho[2,1-b]pyran give the 3-oxobutyl,3-oxoheptyl, and 3-phenyl-3-oxopropyl derivatives of 2-formyl-3-methyl(2H)-1-benzopyran

Journal ArticleDOI
TL;DR: In this article, the crystal structure of 2-amino-4 H -pyran derivatives has been determined by X-ray diffraction and the conformation of the pyran ring is a distorted boat.

Journal ArticleDOI
TL;DR: In this paper, the synthesis of 7a,15a-dlhydro, 15a-methylnaphtho[2,l-b] naphthol [1',2':5,6] pyrano[3,2-e]pyran (II) and 7a 15a -dihydro-7a-mmethyl-15aisopropyi naphTHo [2,1-b], naphthso [1',2' : 5,6]-pyrano [3


Journal ArticleDOI
TL;DR: In this paper, the pyran rings can then be opened by boron tribromide to afford a 4,6-diaryldibenzophosphole.
Abstract: 3,3‴-Dimethyl -2′,2″,4″,6′-tetranitro-5,5‴-di-t-butyl-m-quaterphenyl did not undergo selective alkoxydenitration at the 2′ and 4″ positions, but when acetoxymethyl groups were placed at the 2 and 2‴ positions, treatment with sodium methoxide caused regiospecific cyclization at these positions and formation of a bibenzochromenyl. Other reagents led to a mixture of two regioisomers. The two remaining nitro groups were replaced via a diamine and a di-iodide by a phosphinic ester bridge. The pyran rings could then be opened by boron tribromide to afford a 4,6-diaryldibenzophosphole. The two bromomethyl groups in this intermediate were converted after acetylation into dimethylphosphonomethyl groups and one atropisomer (the meso isomer) was isolated. Some analogous experiments in the biphenyl series are reported.

Journal ArticleDOI
TL;DR: In this paper, the structure of cyclic imino-phosphoranes 3, 5 and 7 was confirmed on the basis of elemental analysis and spectral studies, and when Wittig reaction was carried out on the pyran compound 7, using p-nitrobenzaldehyde, the new olefin 8 was isolated.
Abstract: 2-Benzylidene-1,3-indanedione (2), 4-benzylidene-1,2-diphenyl-3,5-pyrazolidenedione (4) and/or 5-benzylidenebarbituric acid (6) can be converted by reaction with N-phenyliminoketenylidene triphenylphosphorane (1) into pyransubstituted phosphoranes 3, 5 and 7. The structure of the new cyclic imino-phosphoranes 3, 5 and 7 was confirmed on the basis of elemental analysis and spectral studies. Moreover, when Wittig reaction was carried out on the pyran compound 7, using p-nitrobenzaldehyde, the new olefin 8 was isolated.

Journal ArticleDOI
TL;DR: In this paper, the structure of previously misassigned products was proven by NMR techniques and application of the HETNOE method to the distinction between structures 9 and 10 is demonstrated.

Journal ArticleDOI
TL;DR: The pyran ring cleaved product (3) and the tetracyclic chromene (5) were obtained by using a strong electron withdrawing group at C(6) in the benzopyran, and a conformationally mobile lactam ring.

Journal ArticleDOI
TL;DR: The photolysis of 4-acetoxy-2 H -chromene 1a leads to a mixture of o -acetoxyphenyl vinyl ketone 2a, 4-chromanone 3, chromone 4, 3-acetoxyloxygen bond and subsequent disproportionation of the resulting radical 8. The isolation of the 3-substituted chromanones 5 and 6 can be accounted for in terms of a photochemical epoxidation of 1a.

Patent
09 Jul 1987
TL;DR: A method of treating fungal infections in mammals employing 1,3,5-trisubstituted-4- (4hydroxy-2-oxo-pyran-6-yl) pyrazoles is disclosed in this paper.
Abstract: A method of treating fungal infections in mammals employing 1,3,5-trisubstituted-4- (4-hydroxy-2-oxo-pyran-6-yl)pyrazoles is disclosed.

Journal ArticleDOI
TL;DR: In this article, the transallenation reaction of 1,3-bis(dialkylamino)-1,3diethoxy allenes with alkylidenemalonyl chlorides was studied.
Abstract: Reaction of 1,3-bis(dialkylamino)-1,3-diethoxy allenes (1) with alkylidenemalonyl chlorides (2) yields vinylacetylenes (4) and/or 3-methylene-2,4-dioxo-3,4-dihydro-2H-pyranes (5). Mechanistically this reaction is closely related to the transallenation reaction of allenes 1 with dialkylmalonyl chlorides which leads to allene-1,1-dicarboxamides.

Journal ArticleDOI
TL;DR: In this paper, a method for the synthesis of 5-aryl-2-methylthio-4H-pyran-4-ones 4a-h has been developed from the corresponding cinnamoylketene dithioacetals in three successive steps.
Abstract: A novel method for the synthesis of 5-aryl-2-methylthio-4H-pyran-4-ones 4a-h has been developed from the corresponding cinnamoylketene dithioacetals 1a-h in three successive steps. In the first step, 1a-h were oxidized with alkaline hydrogen peroxide to give the corresponding (s-aryl-,a,s-epoxypropanoyl)ketene dithioacetals 2a-h in 78-89% overall yields. In the second step the epoxyketones 2a-h were subjected to rearrangement in the presence of ether-boron trifluoride complex to give the corresponding (a-formyl-a-phenylacetyl)ketene dithioacetals 3a-h, which were then cyclized in the third step by refluxing in acetic acid/ethanol to afford the title compounds in good yields.