CLXV.—Hydroxy-carbonyl compounds. Part II. The benzoylation of ketones derived from phloroglucinol

Reaction of Coumarins with Superoxide Anion Radical (O2): Facile Entry to o‐Coumarinic Acid Systems

“…Aqueous workup yielded 63% of the starting material along with 36% of a new product. r-butyl-o-coumarinate (14). Methyl iodide workup generated a 73% yield of the previously observed 10 as well as 25% of the corresponding r-butyl ester IS.…”

“…Cinnamate 10 was the sole product (SO'}f,) yield) with potassium superoxide. When the z-butoxide reaction was quenched only with aqueous acid, preparative TLC (using 10% acetone in hexane) yielded 63% of the starting material along with an additional product (Rr = 0.1) in a 36% yield, identified as r-butyl o-coumarinate (14).…”

Intermolecular C–O addition of carboxylic acids to arynes: synthesis of o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones

“…44 mp 70 °C); 1 H NMR (400 MHz, CDCl 3 ) δ 0.98 (t, J = 7.4 Hz, 3H), 1.59–1.65 (m, 2H), 2.96 (t, J = 7.3 Hz, 2H), 3.81 (s, 3H), 3.85 (s, 3H), 5.92 (d, J = 2.4 Hz, 1H), 6.06 (d, J = 2.5 Hz, 1H); 13 C NMR (100 MHz, CDCl 3 ) δ 14.0, 18.1, 46.1, 55.5 (×2), 90.7, 93.6, 105.8, 162.7, 165.7, 167.6, 205.8; HRMS (APCI) calcd for [M+H] + C 12 H 17 O 4 225.1121, found 225.1122.…”

An Efficient Synthesis of Coumarin Derivatives Using a SBA-15 Supported Cobalt(II) Nanocatalyst

“…Pechmann condensations generally involve the reaction of phenolic compounds with a carboxylic acid or an ester containing a b-carbonyl group to generate an intermediate that undergoes dehydration to the final coumarin product. Several protocols have extensively covered the synthesis of coumarin derivatives via Pechmann condensation, mostly catalysed by homogeneous acidic catalysts including H 2 SO 4 , P 2 O 5 [10], trifluoroacetic acid [11] as well as different metal salts such as FeCl 3 , TiCl 4 , InCl 3 , ZrCl 4 [12][13][14][15], Bi(NO 3 ) 3 Á5(H 2 O) [16] and Cu(CH 3 CN) 4 PF 6 [17]. The use of homogeneous acid catalysts possesses inherent corrosion, separation, product isolation and purification and catalyst recycling issues, highly detrimental from the practical point of view.…”