6-Methoxy coumarins

The comparison of three coumarin compounds, 4-(bromomethyl)-7-methoxy-coumarin (Br-MMC), 7-(diethylamino)coumarin-3-carbohydrazide (DCCH), and 7-(diethylamino)-3-[(4-(iodoacetyl)amino)phenyl]-4-methylcoumarin(DCIA) as potential chemiluminescence with HPLC was reported by Grayeshi and Vasto (35) (see Chemical Structure 2). 

McKeone et al. proposed to use 7-methoxy coumarin-3-carbonyl azide (7-MCCA) to prepare fluorescent derivatives to be detected with absorption at 340 nm and emission at 370 nm (91). Reversed-phase HPLC was carried out with A/2-P/W (64/25/11) some typical chromatograms are shown in Fig. 8. 

Wittig reagents, which are formed in situ from ethyl 2-chloroacetate and triphenylphosphine, react with salicylal-dehydes under solvent-free conditions to afford coumarins in high yield (Equation 278) <2003PS501>. Methyl 2-hydroxybenzoate reacts with keteneylidene(triphenyl)phosphorane 685 to yield 4-methoxy coumarin, via formation of the ylide intermediate 686 (Scheme 166) <1996J(P1)2799>. 

A comparison of the solid state photochemistry of two crystals, 7-methoxycoumarin and methyl m-bromo-cinnamate, further exemplifies the importance of the existence of free volume near the reaction site (Sch. 15) [127-129], In spite of the fact that the reactive double bonds are rotated by 65° with respect to each other and a center-to-center double-bond distance of 3.83 A (Fig. 16), photodimerization occurs in crystals of 7-methoxy-coumarin to give the syn head-to-tail isomer (Sch. 15). On the other hand, methyl m-bromo-cinnamate, which also has a nonideal arrangement of the... 

Hydroxy-7-methoxy-coumarin] (coumarin) [4-Hydroxy-6,7-methylene-dioxycoumarin] (coumarin) [4 -Hydroxy-5,6,7,8,3 -pentamethoxyflavone] (flavone)... 

The derivative is formed by reaction of an amine with 4-bromomethyl-7-methoxy-coumarin. Cleavage is affected by irradiation at >360 nm in the presence of an H-donor such as C10H21SH in MeOH, 77-90% yield. ... 

Both the approaches mentioned above have intrinsic problems. This may be illustrated with the synthesis of certain specific compounds like 5-methoxy coumarin, naphtho(2,3-b)furan and 8-methoxy isoquinoline. 

The starting compound for the synthesis of 5-methoxy coumarin would be the resorcinol derivative (1), which after demethylation followed by Perkin condensation can afford 5-methoxy coumarin. 

Rabaron et al (24) described a three-parameter correlation of the 13C chemical shifts of various 3-substituted 4-hydroxy- and 4-hydroxy-7-methoxy-coumarins with J-, R and Q (68) ... 

Other reagents used are 4-bromomethyl-7-ace-toxycoumarin (BrMAC), 3-Bromoacetyl-7-methoxy-coumarin (BrAMC). The use of BrAMC allows the derivatization of fatty acids at room temperature. BrAMC has a higher reactivity than other bromomethylcoumarins 4-bromomethyl-6,7-dimethoxycoumarin, 4-bromomethyl-6,7-methylene-dioxycoumarin, 4-bromomethyl-7,8-benzocoumarin, 4-diazomethyl-7-methoxycoumarin, and 7-(diethyl-amino)-coumarin-3-carbohydrazide. 

Berthelot, T. Talbot, J. Lain, G. Deleris, G. Latxague, L. Synthesis of Ne-(7-diethyl-aminocoumarin-3-carboxyl)- and Ne-(7-methoxy-coumarin-3-carboxyl)-L-Fmoc lysine as tools for protease cleavage detection by fluorescence. J. Pept. Set 2005,11,153-160. 

CA Index Name 2/1-1-Benzopyran-3-carboxylic acid, 7-methoxy-2-oxo-, 2,5-dioxo-l-pyrrolidinyl ester Other Names 2,5-Pyrrolidinedione, l-[[(7-methoxy-2-oxo-2//-l-benzopyran-3-yl)carbonyl]oxy]- 7-Methoxy-coumarin-3-carboxylic acid succinimidyl ester Succinimidyl 7-methoxy-2//-chromene-3-carboxylate MCCS... 

C12-C18 soaps alkyl distribution Sewage and sewage sludge Sludge preliminary Soxhlet extraction with petroleum ether to remove lipids, addition of Ci7 internal standard, conversion to soluble salts, Soxhlet extraction with MeOH. Sewage no workup RP-HPLC of p-bromophenacyl bromide derivative-UV detection (254 nm), or 4-bromomethyl-7-methoxy coumarin-fluorescence detection (X xAem = 328/380 nm) 45,176,177... 

Coumarin, 4-methyl-7-methoxy-mass spectra, 3, 608 Coumarin, 4-methylsulfonylmethyl-synthesis, 3, 805 Coumarin, nitro-reduction, 3, 691 Coumarin, 3-nitro methylation, 3, 682 Coumarin, 3-phenoxy-synthesis, 3, 807... 

The nOe difference measurements not only help in stereochemical assignments but also provide connectivity information. A large nOe at 8 6.91 (G-8H), resulting from the irradiation of the methyl singlet of the methoxy group (8 3.94), confirms their proximity in space. This nOe result is consistent with structure A for the coumarin. 

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