Benzopyran

About: Benzopyran is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 15235 citations.

Chiral 2H-Pyrans 1: Separation and photoinduced transformations of the enantiomers of 3′,3′-dimethylspiro[2H-1-benzopyran-2,1′(2)oxaindans]

Abstract: Abstract The enantiomers of spiropyrans of the 2-oxaindan series have been separated by liquid chromatography. The photoinduced ring opening/ring closure of the enantiomers of the 3-methyl derivative 2a is stereoselective.

A new 2-phenyl-4H-1-benzopyran (flav-2-ene) synthesis

Abstract: Phenoxymagnesium bromides react with cinnamaldehyde selectively in the position ortho to the oxy-substituent to yield diphenyl(styryl)methane derivatives (III). When a suitable substituent is located near the position of electrophilic attack, the reaction leads to mixtures of 2-phenyl-4H- and 2H-1-benzopyrans in a ratio which depends on the experimental conditions. The 2H-compounds are converted into the 4H-isomers when heated with alkoxy- or phenoxy-magnesium bromides. This method is the most straightforward route to 2-phenyl-4H-1-benzopyrans (flav-2-enes).

Photoinduced molecular transformations. Part 143. (2 + 2) Photoaddition of 3-hydroxy-1-benzopyran-2-one, 3-benzyloxycarbonyloxy-1-benzopyran-2-one, and their 8-methoxy derivatives, with alkenes and formation of 1,2-disubstituted 1,2-dihydrofuro[2,3-c][1]benzopyran-4-ones by way of β-scission of cyclobutanoxyl radicals generated from the resulting [2 + 2] photoadducts

Abstract: Direct photoaddition of 3-hydroxy-1-benzopyran-2-one with 2,3-dimethylbut-2-ene in tert-butyl alcohol gave tetrahydro-2a-hydroxycyclobuta[c][1]benzopyran-3-one (63%) arising from a (2 + 2) photoaddition while photoaddition of 3-(benzyloxycarbonyloxy)-1-benzopyran-2-one and its 8-methoxy derivative with cyclopentene gave 65:35 and 40 : 60 mixtures of cis-cisoid-cis-(65%) and cis-transoid-cis photoadducts (75%). Removal of the protecting groups of these adducts by hydrogenolysis gave the corresponding cis-cisoid-cis cyclobutanols (37 and 24%, respectively).Similar (2 + 2) photoadditions of the protected 3-hydroxy-1-benzopyran-2-one and its 8-methoxy derivative with cyclohexene gave a mixture of cis-cisoid-cis and cis-transoid-cis adducts, respectively. Removal of the protecting groups from each adduct gave 85 : 15 and 70 : 30 mixtures of the cis-cisoid-cis(86%) and cis-transoid-cis cyclobutanols (70%).Photolysis of the hypoiodites generated in situ from these cyclobutanols induced regioselective β-scissions of the corresponding cyclobutanoxyl radicals to give furo[2,3-c][1] benzopyran-4-ones (20–34%) together with 4-(trans-2-iodocycloalkyl)-1-benzopyran-2-ones (7–25%). The pathways leading to the formation of the products arising from the β-scission are discussed.

Tricyclic benzopyran compound as anti-arrhythmic agents

Abstract: This invention relates to benzopyran derivatives of formula (I) or (II), or pharmaceutically acceptable salts thereof wherein R1 and R2 are independently of each other hydrogen atom, C1-6alkyl group or C6-14aryl group, R3 is hydrogen atom or C1-6alkylcarbonyloxy group, or together with R4 forms a bond, R4 is hydrogen atom, or together with R3 forms a bond, m is an integer of 0 to 4, n is an integer of 0 to 4, V is a single bond, CR7R8, NR9, O, S, SO or SO2, R5 is hydrogen atom or C1-6alkyl group, R6 is hydrogen atom, C1-6alkyl group, C3-8cycloalkyl group, C3-8cycloalkenyl group, amino group, C1-6alkylamino group, di-C1-6alkylamino group, C6-14arylamino group, C2-9heteroarylamino group, C6-14aryl group, C2-9heteroaryl group or C2-9heterocyclyl group, A is 5-, 6- or 7-member ring fused with benzene ring, as constituent atom of the ring, oxygen atom, nitrogen atom or sulfur atom may be contained in the number of 1 to 3 alone or in a combination thereof, the number of unsaturated bond in the ring is 1, 2 or 3 including an unsaturated bond of the benzene ring to be fused, carbon atoms constituting the ring may be carbonyl or thiocarbonyl. These compounds are useful as an anti-arrhythmic agent.