Showing papers on "Benzopyran published in 1982"

Activated nitriles in heterocyclic synthesis: Synthesis of several new coumarin derivatives

Abstract: Several new benzopyran and benzopyranopyridine derivatives were synthesized via condensation of 2-amino-1,1,3-tricyanopropene (1) and diethyl 2-amino-1-cyanopropene-1,3-dicarboxylate (2) with salicylaldehyde and treatment of the resulted products with active methylene regents. The spectroscopic data of the synthesized compounds are reported and discussed.

Synthesis of some pterocarpenes obtained from Brya ebenus

Abstract: The syntheses of bryacarpenes-1, -2, and -4, [4,10-dihydroxy-3,8,9-trimethoxy-(1), 10-hydroxy-3,8,9-trimethoxy-(2), and 4-hydroxy-3,9,10-trimethoxy-6H-benzofuro[3,2-c][1]benzopyran (3)], (±)-bryaflavan [(±)-3′,6,7-trihydroxy-2′,4′-dimethoxyisoflavan (33)], 4-hydroxy-3,7-dimethoxy-(18) and 3,7-dimethoxy-6H-benzofuro[3,2-c][1]benzopyran-9,10-quinone (19) is described. The quinones are not identical with bryaquinone and deoxybryaquinone, for which structures (18) and (19) had been proposed previously. In the syntheses of the pterocarpenes the novel reduction of isoflavones to isoflavan-4-ones by di-isobutylaluminium hydride was used.

IMPROVEMENTS IN THE SYNTHESIS OF A KEY α‐TOCOPHEROL INTERMEDIATE ‐ (S)‐(‐)‐3,4‐DIHYDRO‐6‐HYDROXY‐2,5,7,8‐TETRAMETHYL‐2H‐1‐BENZOPYRAN‐2‐ACETIC ACID

Abstract: The (S)-(−)-chroman-2-acetic acid 5 and its derivatives are plvotal intermediates in various total syntheses of natural (2R,4′FJ,E′FJ)- a- tocopherol (1) developed in our laboratories. 1–5 Certain of these convergent schemes,1–3 involving coupling of C15-chroman and C14-side chain units possessing very high enantiomeric and diastereomeric purities, have also proven useful for construction of all 7 stereoisomers of natural a-tocopherol.6

Novel benzopyran derivative

Abstract: NEW MATERIAL:A compound of formula I (P is 3,4-dihydro-2H-1-benzopyran ring; A is direct bond or -O-CH2; B is direct bond, alkylene, etc.; R is H, halogen, lower alkyl,alkoxyl,alkyleneoxy, etc.; R1 and R2 are H, alkyl, hydroxyalkyl, etc.; R3 is H or nitro; m and n are 1 or 2). EXAMPLE:3,4-Dihydro-8-[ (2-hydroxy-3-isopropylamino)propoxy ]-3-nitratomethyl- 2H-1-benzopyran. USE:An antistenocaridiac agent, hypotensive agent, ameliorant of cerebral circulation and antiarrhythmic agent. PROCESS:A compound of formula II (Q is OH, ethoxycarbonyloxy, acetoxy, etc.) is nitrated and converted into an aminoalkanol derivative thereof to give a compound of formula III. The resultant compound is then nitrated at room temperature to 90 deg.C to afford the compound of formula I.

Benzopyran compound and coloring of organic high-molecular material by use of same

Abstract: NEW MATERIAL:A benzopyran compd. of formula I, wherein R1 and R2 are each H, straight-chain or branched alkyl, halogen, cyano, (carbo)alkoxy, aryl (oxy), acetoxy-substd. alkyl, cycloalkyl or phenyl, where R1 and R2 may constitute a heterocyclic residue in combination with each other; X is imino or O; Y, and Y2 are halogen; m and n are 1-3 where m+n=2-4. USE:A colorant for coloring a fiber or a molded product consisting of an org. high- molecular material in bright red with excellent fastness. PREPARATION:It is obtd. by the reaction of an imino-coumarin of formula II with a malonodinitrile of formula III in an org. solvent (e.g.,dimethyl-formaldehyde) at 50-200 deg.C, followed by hydrolysis in the presence of an acid, e.g., HCl.

Electron impact mass spectrometry of 2-hydroxymethyl-3,4,5,6,7,8-hexahydro-2 H-1-benzopyran-5-ones. The unusual presence of [MH3O]+ species in the fragmentation pattern of 4-phenyl derivatives†

Abstract: The mass spectrometric behaviour of some 2-hydroxymethyl-3,4,5,6,7,8-hexahydro-2H-1-benzopyran-5-ones is described and discussed with the aid of exact mass measurements, linked scans, labelling experiments and low electron energy measurements. The unusual presence of abundant [MH3O]+ species in the mass spectra of 4-phenyl substituted compounds is discussed in detail and a mechanism is proposed.

Lactonization of o-Arylethenylbenzoic acids: Formation of 3,4-dihydro- 1 H-2-benzopyran-1-ones and isobenzofuran- 1(3H)-ones

Abstract: The formation of six 3,4-dihydro-1H-2-benzopyran-1-ones (2a-f) and one isobenzofuran-1(3H)-one (3a) from o-arylethenylbenzoic acids (1) in neutral or acid solution is described. The benzoic acids having a neutral or electron-releasing group on the double bond give δ-lactones (2), whereas compounds with a strong electron-withdrawing group give the γ-lactones (3). The mechanism is discussed in terms of electronic effects. The rate of cyclization of the (Z)-compound is found to be faster than that of the (E)-compound.

Benzopyran compounds, pharmaceutical compositions containing them and methods of use

Abstract: The present invention provides benzopyranyl ethers of the general formula: ##STR1## wherein A is an alkylene radical containing 2 to 4 carbon atoms and R is a hydrogen atom or an acyl radical; as well as the salts thereof with pharmacologically acceptable acids. The present invention also provides processes for the preparation of these compounds and pharmaceutical compositions containing them. Furthermore, the present invention is concerned with the use of these compounds for treating allergic diseases.

Benzopyran compound and coloring method of organic high-molecular material employing the same

Abstract: NEW MATERIAL:Benzopyran compounds of formula I wherein X is imino or O; Y is methyl, methoxy, or halogen; Z is H or halogen. USE:Dyes which dye polyesters, cellulose acetate and PVC clear red. PREPARATION:An imino coumarin compd. of formula II is reacted with malononitrile of formula III in an org. solvent such as isopropanol at 50-200 deg.C. These dyes exhibit good affinity with hydrophobic fibers and have excellent build-up properties.

Activated nitriles in heterocyclic synthesis: synthesis of several new coumarin derivatives

Abstract: Several new benzopyran and benzopyranopyridine derivatives were synthesized via condensation of 2-amino-1,1,3-tricyanopropene (1) and diethyl 2-amino-1-cyanopropene-1,3-dicarboxylate (2) with salicylaldehyde and treatment of the resulted products with active methylene regents. The spectroscopic data of the synthesized compounds are reported and discussed.

Pyrylocyanines. 15. Benzopyrylo-2-cyanines

Abstract: Symmetrical 4,4′-diphenyl-substituted benzopyrylo-2-monomethylidyne, carbo-, and dicarbocyanines and their thio analogs, as well as unsymmetrical carbocyanines that contain, in addition to 4-phenylbenzopyrylium or 4-phenylbenzothiopyrylium rings, 3-ethylbenzothiazolium or 1,3,3-trimethyl-3H-indolium residues, were synthesized. The indicated dyes were more highly colored than their isomers that contain flavylium or thioflavylium residues. On the basis of the deviations calculated from the centers of the absorption bands it was concluded that the benzopyran residues in the dyes of the α series have greater electron donor character than those in the dyes of the γ series.