7.8- Dihydroxy 4-methyl coumarin

Dihydroxy-4-methyl-2H-1-benzopyran-2-one. See 5,7-Dihydroxy-4-methyl coumarin... 

Methyl-5,7-dihydroxycoumarin. See 5,7-Dihydroxy-4-methyl coumarin Methyl Di-lcinol. See Methoxydiglycol Methyl dimethylacetate. See Methyl isobutyrate Methyl trans-2,3-dimethylacrylate. See Methyl tiglate... 

Dihydroxy-4-methyl- coumarin) (coumarin) 4 -0-Methyl-OTt- Panda oleosa (Pandaceae) COX-1, COX-2... 

Formylation of 5,7-dihydroxy -( -propyl)-coumarin (1) provided on 8-formy-lated product (26). Treatment of the compound 26 with 3-chloro-3-methyl-l-butyne to introduce regioselectively the chromene 27 because the phenolic hydroxyl group at the C position was less accessible for formylated substitution because of a presumed hydrogen-bonding interaction. To construct the enantiomerically pure rra i-2,3-dimethyl chroman-4-ol system, Deshpande et al." ° used organoborone... 

Pechman condensation may also be exemplified by the S3mthesis of a 4-substituted coumarin, wherein a dihydroxy phenol (e.g., resorcinol) may be condensed with ethyl acetoacetate under the influence of sulphuric acid to give rise to the formation of 7-hydroxy-4-methyl coumarin. 

Other Names Coumarin, 6,7-dihydroxy-4-methyl- Esculetin, 4-methyl- 4-Methyl-6,7-dihydroxy-coumarin 4-Methylaesculetin 4-Methylesculetin 4-Methylesculetol 6,7-Dihydroxy-4-methyl-coumarin Methylesculetin NSC 11828 NSC 688807 CA Index Name 2H-l-Benzopyran-2-one, 6,7-dihydroxy-4-methyl-CAS Registry Number 529-84-0 Merck Index Number Not listed Chemical Structur... 

B. Tyagi et al. described the synthesis of 5,7-dihydroxy 4-methyl cou-marin and 7,8-dihydroxy 4-methyl coumarin using nanocrystalline sulfated-zirconia catalyst in solventless system under MWI at 130 °C within 5-20 min in 78-85% yields (08JMCCF241). 

Amino-4,7-dihydroxy- [4-Hydroxy-3 (3-methyl-2-8-methyl coumarin] butenyl)benzoic acid]... 

Lasius fuliginosus W-HG Trail following antennal responses (3R)-(-)-3,4-Dihydro-8-hydroxy-3-methyliso-coumarin 129 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one 134 [175]... 

The 3-amino-4,7-dihydroxy-coumarin moiety is a core unit of this family of compounds. The amino group of coumarin scaffold is further decorated with derivatives of pyrrole or benzoic acid moieties. Also, branched deoxysugar 5-C-methyl-L-rhamnose (noviose) is installed onto one of the hydroxyls of the coumarin. Clorobiocin 67 and novobiocin 68 can be considered prototypical aminocoumarins. These molecules are potent inhibitors of bacterial gyrase and topo-isomerase IV and 68 is used to treat human infections. Several works also showed that analogs of 68, in combination with other drugs, can improve the chemotherapy of certain tumors [121]. 

A solution 35.6 g of 4-chlormethyl-6,7-dihydroxycoumarin and 27.3 g of morpholine in 4.5 L methyl ethyl ketone was refluxed for 9 hours. On cooling the morpholine hydrochloride was deleted. Methyl ethyl ketone was evaporated in vacuum. The solid product was mixed with 500 ml of water and dried in vacuum with P205. Yield of crude 6,7-dihydroxy-4-(morpholinomethyl)coumarin is 41.5 g. After recrystallization from ethanol was obtained 6,7-dihydroxy-4-(morpholinomethyl)coumarin with M.P. 232°C. 

In the alternate approach, selective methylation117,138) of the dihydroxy-coumarin (55) produced the 7-methyl ether (56) as the major product, which was readily benzylated to afford (49). In both of the above cases, the regiochemical nature of the compounds was ascertained by spectral comparisons with a known compound (50) and the compounds directly derived therefrom137). 

The biosynthesis of novobiocin has been reviewed 52, and the formation in cell-free extracts of novobiocic acid has been described 53. The latter can be formed from 3-am1no-4, 7-dihydroxy-8-methvl coumarin (B ring) and 4-hydroxy-3(3-methyl-2-butenyl)benzoic acid (A ring) by an enzyme that forms an amide bond between these precursors. Energy (ATP) is required but the mode of activation of the carboxyl group is unknown. Novobiocin itself possesses a sugar (noviose) but its biosynthesis and the formation of the glycosidic link are little studied 52. 

Phenylketonuria can be induced experimentally using various phenylalanine derivatives. Among these are phenylalanine alkylating agents [236] and several o-dihydroxy derivatives [237-239] particularly esculetin (6,7-dihydroxy-coumarin) derivatives were found to be very potent in inhibiting phenylalanine hydroxylase both in vivo and in vitro [240, 241]. This observation led to further structure-activity studies applying different 3- and 4-substituted 6,7-dihydroxy-coumarins. In vitro 4-methyl-, 4-butyl- and 4-pheny -6,7-dihydroxycoumarin, and in vivo esculin, 4-methyl- and 4-phenyl-6,7-dihydroxycoumarin appear to be the most powerful inhibitors of the rat liver enzyme (Table 3,7). 

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