H-Chromen-4-one

ATBO 4-amino-7,8,9,10-tetrahydro-2//-benzo [h] chromen-2-one analogs... 

Antitumor agents 278. 4-Amino-2H-benzo[h]chromen-2-one (ABO) analogs as potent in vitro anti-cancra- agcmts. Bioorg Med ChemLett 20 4085... 

Angelicin 2H-Furo[2,3-h]chromen-2-one Apiaceae Angelica sp. [294,295] Pastinaca sativa [296] Ammi majus [296] Apium graveolens [287] Heracleum laciniatum [273] Leguminosae Bituminaria hituminosa [297] Moraceae Ficus carica [272]... 

On the other hand, refluxing 9 in formic acid for 5 h afforded the N-formyl derivative 11 in high yield. Acetylation of 9 by refluxing in acetic acid, afforded acetic acid N -(2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-acetyl)-hydrazide 12 in good yield. Compound 13 was also obtained by refluxing 9 with 3-(2-bromoacetyl)-4-hydroxy-2H-chromen-2-one in ethanol. Reaction of compound 9 with phenyl isothiocyanate in ethanol at room temperature gave 4-phenyl-1 - (7-hydroxy-2-oxo-2 H-chromen-4-acetyl- )thiosemicarbazide 14. 

The reaction of 2/f-chromene-3-carboxaldehyde (168, R = H) with p-fluoro-benzaldehyde in the presence of an NHC and base was expected to produce a lactone, via homoenolate chemistry of (168). Instead, 3-methyl-2//-chromene-2-one (169, R = H, i.e. 3-methylcoumarin) was formed. The unexpected result was obtained again with the benzaldehyde omitted. Using a 2-methyl substrate (168, R = Me) results in a similar product, that is, 3-et/iy/coumarin (169, R=Me). ... 

Other Names Coumarin, 7-hydroxy-4-methyl- Umbelliferone, 4-methyl- P-Methylumbelliferone 4-MU 4-Methyl-7-hydroxycoumarin 4-MethylumbelUferone 7-Hydroxy-4-methyl-2-chrome-none 7-Hydroxy-4-methyl-2-oxo-3-chromene 7-Hydroxy-4-methyl-2H-l-benzopyran-2-one 7-Hydroxy-4-methyl-2H-chromen-2-one 7-Hydroxy-4-melhylcoumarin BilcoUc Bilicante Bili-ton H Cantabilin Cantabiline Cholestil Cholonerton Cholspasmin Coumarin 4 Coumarin 456 Cumarote C Eurogale Himecol Hymecromone Imecromone LM 94 Medilla Mendiaxon NSC 19026 NSC 9408 Omega 127 Pilot 447 CA Index Name 2H-l-Benzopyran-2-one, 7-hydroxy-4-methyl-CAS Registry Number 90-33-5 Merck Index Number 4854 Chemical Structure... 

Cao, H. and Xiao, W.-J. (2005) Microwave-accelerated, palladium-catalyzed carbonylative cychzation reactions of 2-iodophenol with alkynes. Rapid and efficient synthesis of chromen-2-one derivatives. Canadian Journal of Chemistry, 83, 826-831. 

In a dry and argon-flushed flask, zinc dust (Aldrich 325 mesh, 1.95 g, 30 mmol activated by 1,2-dibromoethane) is suspended in THF (3 mL). A solution of 4-iodo-chromen-2-one (229 2.72 g, 10 mmol) in THF (3 mL) is added dropwise over 15-20 min. The reaction mixture is stirred 4 h at 45 °C, until GC analysis of hydrolyzed reaction aliquots show completion of the reaction. THF (8 mL) is added and the excess zinc is allowed to settle for 1-2 h at 25 °C. The yield of the alkenylzinc iodide 228 is estimated to be 80%. 

Thakrar et al. (2013) synthesized a new series of highly functionalized 1,5-ben-zodiazepine derivatives from 3-[(lE)-N-(2-aminophenyl)ethanimidoyl]-4-hydrox-yl-2H-chromen-2-one and pyrazole aldehyde using catalytic amount of trifluoro-acetic acid under microwave irradiation. The major advantages of this process is its shorter reaction time (reduced from 8-10 h to 15-20 min), easy work up procedure, and excellent yield with high purity. 

In the presence of a ruthenium catalyst, 3-diazochroman-2,4-dione 716 undergoes insertion into the O-H bond of alcohols to yield 3-alkyloxy-4-hydroxycoumarins 717 (Equation 285) <2002TL3637>. In the presence of a rhodium catalyst, 3-diazochroman-2,4-dione 716 can undergo insertion into the C-H bond of arenes to yield 3-aryl-4-hydroxy-coumarins (Equation 286) <2005SL927>. In the presence of [Rh(OAc)2]2, 3-diazochroman-2,4-dione 716 can react with acyl or benzyl halides to afford to 3-halo-4-substituted coumarins (Equation 287) <2003T9333> and also with terminal alkynes to give a mixture of 477-furo[3,2-f]chromen-4-ones and 4/7-furo[2,3-3]chromen-4-ones (Equation 288) <2001S735>. 

The carbon chain functionalised with the chromone nucleus characterises the patented saccharin derivatives 412 as agents for treating disorders of the central nervous system. As an example, the synthesis of (R)-(-)-[2-[4- (benzyl [7-(benzyloxy)-6-methoxy-3,4-dihydro-2ff-chromen-2-yl]methyl-amino)-2-butynyl]-l,2-benzisothiazol-3(2ff)-one S,S-dioxide (412 = H,... 

However, when 36 was heated with a-amino heterocycles or with cyclic 1,3-dicarbonyl or potential 1,3-dicarbonyl compounds, 3-heteroarylp)rr-azol derivatives were obtained. In this manner 36 afforded, when heated with 2-aminopyridine and 3-amino-lH-pyrazol in acetic acid under reflux for 2 h and 5 h, respectively, 3-(5-ethoxy-l-phenyl-lH-pyrazol-3-yl)-4H-pyrido[l,2-fl]pyrimid-4-one (38) and 6-(5-ethoxy-l-phenyl-lH-p5rrazol-3-yl)pyrazolo[l,5-fl]pyrimid-7(lH)-one (39) in 70% and 77% 5deld, respectively. Similarly, 36 afforded with cyclicjS-dicarbonyl compounds, such as 4-hydroxy-6-methyl-2H-pyran-2-one and 5,5-dimethylcyclohexane-l,3-dione by heating in acetic acid for 4 h and 8 h, respectively, the corresponding 3-(5-ethoxy-l-phenyl-lH-pyrazol-3-yl)-7-methyl-2H,5H-pyrano[4,3- 7]pyran-2,5-dione (40) and 3-(5-ethoxy-l-phenyl-IH-pyrazol-3-yl)-7,7-dimethyl-7,8-dihydro-2H-chromene-2,5-dione (41) in 26% and 82% yield, respectively (Scheme 15). 

A solution of 5,7,8-trimethoxy-chromen-4-one 25 (500 mg, 2.1 mmol) in acetic anhydride (7 mL) was refluxed with hydroiodic acid (10 mL) for 2 h at 120 °C. After cooling to room temperature, the reaction crude was quenched with slow addition of aqueous saturated sodium sulfite solution, during which the product started to precipitate as a yellow powder. Filtration followed by recrystallization from methanol afforded 5,6,7-trihydroxy-chromen-4-one (26) as yellow needles (100 mg, 0.5 mmol, yield 25%). mp, 172-173 °C. 

A solution of cyclic 1,3-dicarbonyl compound (1 1.0 mmol)/ 4-hydroxycoumarin (5 1.0 mmol), arylaldehyde (2 1.0 mmol), NMSM (3 1.0 mmol), and piperidine (20 mol%) in etahnol (2 mL) was stirred at room temperature for the appropriate time (2-5 h). On completion of the reaction (as indicated by TLC), the product (4/6) was filtered and washed with etahnol (2 mL) to remove the excess base and other impurities. Pure chromen-5-ones (4)/pyrano[3,2-c] chromen-5-ones (6) were obtained when recrystallized from EtOH. All the products were characterized from spectral (IR, NMR, NMR, MS) and elemental analyses. 

Obtained by slowly adding 3 M sodium hydroxide to a solution of 4,9-dimethoxy-7-methylfuro[3,2-g] chromen-5-one in refluxing dilute ethanol, then the resulting solution was stirred at 70° for 3 h [4288]. 

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