5891-82-7Relevant academic research and scientific papers
Infrared Spectra and Theoretical Study of Methyl, Formyl and Acetyl Derivatives of Chromones
El-Shaaer, Hafez Mohamad El-Metwall,Perjessy, Alexander,Zahradnik, Pavol,Lacova, Margita,Sustekova, Zora
, p. 539 - 548 (1993)
The C=O stretching frequencies of substituted 2-methylchromones (3a-j), 2-formylchromones (4a-j), 3-formylchromones (5a-j) and 3-acetyl-2-methylchromones (6a-i) were measured in CCl4 and CHCl3 and correlated with ?+ substituent constants.Using the results of the infrared spectral investigation and the theoretical calculations by the semiempirical AM1 methd, the conformation and the transmission of electronic effects in compounds 4-6 were studied.For the 2-substituted chromone system the transmission factory γ according to the definition of Charton was determined.The preparation of some new 2-methylchromones (3e-j) and 3-(2,2-diformyl-chlorovinyl)-6-methylchromone (7) is also described. Key words: 2-Methyl-, 2-formyl-, 3-formyl-, and 3-acetyl-2-methylchromones; infrared spectra; AM1 calculations; conformation; transmission of substituent effects.
A novel and efficient synthetic method of benzo[f]chromen-1-ones and phenyl-4h-chromen-4-one through photooxidative cyclization of 6-[(E)-2-arylvinyl]-4H-pyran-4-ones and 6-[(1E,3E)-4-phenylbuta-1,3-dien-1-yl]-4H-pyran-4-one
A?t-Baziz, Nabila,Hamdi, Safouane M.,Silva, Artur M.S.,Rachedi, Yahia,Hamdi, Maamar,Trari, Mohamed
, p. 1240 - 1245 (2015/04/27)
A rapid and efficient microwave-assisted transformation of 2-pyrones into 4-pyrones is reported. Then, a new photocatalytic oxidative cyclization of 6-[(E)-2-arylvinyl]-2-methyl-4H-pyran-4-ones and 2-methyl-6-[(1E,3E)-4-phenylbuta-1,3-dien-1-yl]-4H-pyran-
Tandem reactions leading to bicyclic pyrimidine nucleosides and benzopyran-4-ones
Fan, Xuesen,Wang, Yangyang,Qu, Yingying,Xu, Haiyun,He, Yan,Zhang, Xinying,Wang, Jianji
supporting information; experimental part, p. 982 - 985 (2011/03/22)
A novel, rapid, and efficient synthesis of bicyclic pyrimidine nucleosides and benzopyran-4-ones through oxidation of homopropargyl alcohols and subsequent isomerization, intramolecular addition of enol to allenic ketone has been developed. This methodology provides an efficient and promising approach to the structurally and pharmaceutically interesting pyrano[2,3-d]pyrimidine-2,5-dione nucleoside and benzopyran-4-one derivatives.
Thallium(III) p-tosylate mediated oxidative rearrangement in substituted chromanones: A novel approach to the synthesis of substituted chromones and tetrahydroxanthones
Singh, Om V.,George, Varughese,Kapil, Randhir S.
, p. 856 - 864 (2007/10/03)
On treatment with thallium(III) p-tosylate, subtituted chromanones undergo smooth dehydrogenation to afford substituted chromones while 2,2-dialkylchromanones undergo oxidative 2,3-alkyl migration to yield 2,3-dialkylchromones in high yields.The migratory aptitude of different alkyl groups with respect to methyl group has also been studied. 2-Spirochromanones undergo oxidative 2,3-alkyl migration to afford tetrahydroxanthones which on dehydrogenation with DDQ afford xanthones in good yields.
Photochemical transformations in 1-(o-hydroxyaryl)-1,3-diketones
Garg, S.,Ishar, M. P. S.,Sarin, R.,Gandhi, R. P.
, p. 1123 - 1128 (2007/10/02)
Irradiation (using pyrex glass filter) of o-hydroxybenzoylacetophenone (1a), o-hydroxybenzoylacetone (1b), 2-hydroxy-1-naphthoylacetophenone (5a), 2-hydroxy-1-naphthoylacetone (5b) and 1-hydroxy-2-naphthoylacetone (9) in Br2/CHCl3 and I2/MeOH solutions leads to various chromone derivatives.Parallel reactions of these 1,3-diketones in the dark record no perceptible change in them.Enhanced photoenolisation of the diketones, in the presence of bromine or iodine, is deemed to be the key step in these transformations.
On the Spectral Properties of Some Fused 4-Methylcoumarins
Maruyama, Junko,Ito, Keiichi
, p. 1178 - 1182 (2007/10/02)
Preparations of the ring-fused 4-methylcoumarins 2-10 were reexamined, and the nuclear magnetic resonance (NMR), ultraviolet (UV) and fluorescence spectral characteristics were determined.Fluorescence properties were found to be sensitive to the type and the position of the ring fused to the parent 4-methylcoumarin 1.The angularly benzo-fused 3 was highly flurescent, whereas the linearly benzo-fused 4 and the pyrono-fused 7 and 9 were only weakly fluorescent.Keywords benzocoumarin; pyronocoumarin; 1H-NMR; UV; fluorescence spectrum; fluorescence quantum yield
A Fresh Look at the Pechmann Condensation and Duff Rection with β-Naphthol
Kostova, I. N.,Pardeshi, N.,Rangaswami, S.,Lee, Yue-Wei
, p. 859 - 862 (2007/10/02)
Pechmann condensation of β-naphthol with ethyl acetoacetate in the presence of anhydrous aluminium chloride gives, besides two known compounds, 4-methyl-6,7-benzocoumarin and 3-methyl-9-hydroxyphenalen-1-one (I).The Duff reaction of β-naphthol gives the new compounds 1,3-diformyl-2-naphthol and 2-formyl-2,3-dihydro-1H-naphth-oxazine (II) and the known 2,2'-dihydroxy-1,1'-binaphthylmethane.Compound (II) exists as a mixture of rotamers.
