Standard molar enthalpies of formation in the crystalline phase of 7-hydroxy-4-methylcoumarin, 7-ethoxy-4-methylcoumarin, and 6-methoxy-4-methylcoumarin

Revision and Extension of a Generally Applicable Group-Additivity Method for the Calculation of the Standard Heat of Combustion and Formation of Organic Molecules

“…A considerable number of experimental combustion and formation data have been published for heterocyclic compounds, including hetarenes, unsubstituted and substituted by functional groups just mentioned. According to the hetero elements in the ring system, they have been subdivided into N x -heterocycles (where x is 1 to 4) , N,O-heterocycles [424][425][426][427][428][429][430][431][432][433], N,S-heterocycles [434][435][436][437][438], O x -heterocycles [439][440][441][442][443][444][445][446][447][448][449][450][451][452], and S x -heterocycles [280,[282][283][284][453][454][455][456][457][458][459][460][461]. A small number of papers contributed data for hetarenes with several element combinations [462][463][464]…”

Synthesis of Coumarin Derivatives Coupled to Amino Acid Esters and Studying their Biological Activity as Antimicrobial Agents

“…They are also known as benzo-2-pyrones. These compounds and their derivatives represent a broad class of natural and pharmaceutical products (1) .This group of compounds has been isolated from a variety of plant sources. Coumarin was first isolated in 1820 by Vogel from the seeds of Tonka beans (coumarouna adorata)…”

“…The solvent was evaporated to dryness under vacuum, re-dissolved in methanol and evaporated, this process was repeated several times and re-crystallize the product from methanol-diethyl ether. Percent yield, physical appearance, m.p, R f values were listed in table (1), and IR characteristics absorption bands were listed in table (2).…”

“…A suspension of Methionine (10mmol, 1.5g) dissolved in (15ml) of absolute methanol and (10mmol, 0.75ml) of thionyl chloride, then complete the procedure as mentioned in the synthesis of A.1. Percent yield, physical appearance, m.p, R f values were listed in table (1), and IR characteristics absorption bands were listed in table (2). (17) A suspension of 4-methyl-7hydroxy coumarin (39.7mmol, 7g) in acetone (70ml) was refluxed with ethyl bromoacetate (59.55mmol, 6.5ml) and anhydrous K 2 CO 3 (218.3mmol, 30g) for 16 hr.…”

“…after cooling, the mixture was evaporated to dryness. The residue was recrystallized from acetone to give off-white powder of 4-methyl-7-(methoxy ethyl acetate) coumarin.Percent yield, physical appearance, m.p, R f values were listed in table (1), and IR characteristics absorption bands were listed in table (2). (18) Compound (B) (26.7mmol, 7g) was dissolved in (100ml) of absolute ethanol and (42ml) of 5% NaOH solution was added, the reaction mixture was stirred overnight at room temperature, then the solvent evaporated, and the residual was dissolved in water and acidified with 6 N of HCl.…”