Thesis On Coumarins

Coumarins can be subdivided into two categories: (1) benzo-α-pyrone commonly called as coumarins (2) benzo-ϒ-pyrones called as chromones or flavanoids, differs only in the position of carbonyl group on the heterocyclic system. 1: 2-H CHROMEN-2-ONE COUMARIN Some important compounds isolated from coumarin are Warfarin, Acenocoumarol, Armillarisin A, Novobiocin, Clorobiocin, Hymecromone etc.

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some mannich base of 5-methyl-[(2-oxo-2H-chromen-3-yl) carbonyl]-2,4-dihydro-3H-pyrazol-3-one (Fig.

20) by using conventional and non conventional (microwave) techniques.

Ethyl 2-oxo-2H-chromene-3-carboxylate was prepared by cyclization of salicylaldehyde with diethylmalonate in presence of catalytic amount of piperidine.

Reaction of this ester compound with hydrazine hydrate in ethanol formed 2-oxo-2H-chromene-3-carbohydrazide.

Activity of other compounds indicated that the presence of an additional fused benzene ring between the C-5` and C-6` positions inhibited the antibacterial activity towards ) compared to in Potato Dextrose Broth medium (PDB).

Appropriate volumes of tested compounds were added to produce concentrations ranging from 10 to 100μg/m L. 12) and (Fig.13) showed good activity as antifungals compared to the antifungal ability of fluconazole, which was used as a standard drugs. 12 FIG.13 4-Heteroaryl-coumarin-3-carbaldehydes Streptomycin was used as standard anti-bacterial drug and ketoconazole was used as standard anti-fungal drug. 17) had activity equal to that of standard drug ketoconazole (31.25 μg/m L) against ntiinflammatory and analgesic activity: Parmar V et al synthesized 4-methyl coumarin derivatives 7,8-dihydroxy-3-ethoxycarbonyl methyl -4-methylcoumarin (DHEMC) and 7,8-diacetoxy-3 - ethoxycarbonylmethyl - 4 - methylcoumarin (DAEMC) (Fig.Therefore, the condensation of pyrazolone with formaldehyde (60%) and various aromatic primary amines resulted in the formation the corresponding Mannich base derivatives.Antiinflammatory activity was evaluated by carageenan induced paw oedema in albino rats.Environmental conditions and seasonal changes can influence the occurrence in diverse parts of the plant .Although most of the natural coumarins in existence have been isolated from the higher plants, some members have been discovered in microorganisms.Specifically, coumarin-3-sulfonamides and carboxamides were reported to exhibit selective cytotoxicity against mammalian cancer cell lines.The C4-substituted aryloxymethyl, arylaminomethyl, and dichloroacetamidomethyl coumarins, along with the corresponding 1-azacoumarins, have been demonstrated to be potential anti-microbial and anti-inflammatory agents.All the synthesized compounds showed activity against both gram positive and gram negative bacteria but lesser activity compared to standard drug. 9 Patel et al synthesized some 4-aryl-2,6-di(coumarin-3-yl)pyridines by the reaction of 3-coumarinoyl methyl pyridinium salts with1-[2H-1-benzopyran-2-on-3-yl]-3-aryl-prop-2-ene-1-ones in the presence of ammonium acetate and acetic acid under the Krohnke reaction conditions (Fig. All the synthesized compounds were screened for antimicrobial activity.None of the compounds showed activity against either in the coumarin nucleus or in the phenyl ring did not affect the antibacterial activity much more and all the compounds have the same activity.19) by using Pechman condensation of pyrogallol with ethyl acetoacetate by introduction of an ethoxycarbonylmethyl group at C-3 position. Both were examined on the inflammatory process induced by lipopolysaccharide (LPS) in activated primary rat microglial cultures by Anna Rita Togna et al and thromboxane were inhibited in the presence of 100µM of DHEMC and DAEMC.Their experimentation showed that 4-methyl coumarin derivatives can modulate inflammatory pathways in microglial cells, probably by acting at the protein expression level.