4-Methyl-7-methoxycoumarin

A wide variety of other esters has been made, or may potentially be accessible, by the type of procedure outlined in this section. To give a couple of examples, the naphthacyl esters were made for improved detectability in HPLC analysis in the same way as the phenacyl esters mentioned earlier [102], the fluorescent esters of 4-methyl-7-methoxycoumarin were made from the 4-bromomethyl-7-methoxycoumarin by the potassium salt procedure [103] and anthrylmethyl esters were obtained by an extractive alkylation procedure [104]. 

Methyl-7-methoxycoumarin and 85%-hydrazine hydrate refluxed 6 hrs. on a steam bath resorcinol monomethyl ether and 3-methyl-5-pyrazolone. Y 65-75%.—The above behavior differs markedly from that of the 3-subst. cou-marin, which yields an o-hydroxybenzaldehyde. F. e. s. G. B. Marini-Bettdlo, G. G. Casinovi, and I. L. de Albuquerque, G. 9A, 366 (1964). 

Elbert, W. Breitenbach, S. Neftel, A. Hahn, J. 4-Methyl-7-methoxycoumarin as a fluorescent label for high-performance liquid chromatographic analysis of dicarboxylic acids. J. Chromatogr. 1985, J2S, 111-120. 

Zelenski, S. G. Huber, J. W, III,. Application of 4-methyl-7-methoxycoumarin derivatives to the high pressure liquid chromatographic analysis of fatty acids. Chromatographia 1978,11, 645-646. 

For more specific analysis, chromatographic methods have been developed. Using reverse-phase columns and uv detection, hplc methods have been appHed to the analysis of nicotinic acid and nicotinamide in biological fluids such as blood and urine and in foods such as coffee and meat. Derivatization techniques have also been employed to improve sensitivity (55). For example, the reaction of nicotinic amide with DCCI (AT-dicyclohexyl-0-methoxycoumarin-4-yl)methyl isourea to yield the fluorescent coumarin ester has been reported (56). After separation on a reversed-phase column, detection limits of 10 pmol for nicotinic acid have been reported (57). 

CijHijNOj 83073-63-6) see Tilisolol hydrochloride l-methyl-2-[[4-(methoxycarbonyl)phenyl]methyl]-l,2-hy-drazinedicarboxylic acid bis(phenylmethyl) ester (CifiHjgNjOg) see Procarbazine 5-methyl-8-methoxycoumarin... 

An improved route to fluorinated 4-hydroxycoumarins has been reported, based on a facile decarboxylation-deacetylation of their 3-(3-oxopropanoic acid) derivatives <96TL15S1>. The reaction of methyl salicylates with triphenylphosphoranylidene ketene, Ph3P=C=C=0, affords 4-methoxycoumarins <96JCS(P1)2799> and the formation of coumarin 3-phosphonates from salicylaldehydes and phosphonoacetates, Et02CCH2P(0)(0R)2, has been investigated <96T12597>. 

A comparison of the photobehavior of two crystals, 7-methoxycoumarin (19) and methyl m-bromo-cinnamate (20), exemplifies the importance of the need for the existence of free volume close to the reaction site [133-135]. Neither of these molecules is topologically oriented for efficient reaction in the crystal, meaning that the reactive pairs need to undergo some inter-molecular realignment before they can dimerize. 

Figure 4 Duration of irradiation versus yield-irradiation time given in hours for 7-methoxycoumarin and 7-chlorocoumarin (topochemical reaction) irradiation in days for 4-methyl-6-chlorocoumarin (defect-initiated reaction)...

Schade, B., Hagen, V., Schmidt, R., Herbrich, R., Krause, E., Eckardt, T. and Bendig, J. (1999) Deactivation behavior and excited-state properties of (coumarin-4-yl) methyl derivatives. 1. Photocleavage of (7-methoxycoumarin-4-yl)methyl-caged acids with fluorescence enhancement. Journal of Organic Chemistry, 64, 9109—9117. 

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... 

No or only minimal cytotoxicity of most coumarins could be detected in normal cells in contrast to the positive control gallic acid. On the other hand, several of them showed concentration-dependent cytotoxicity against tumor cell lines HSC-2 and HSC-3. Among them, 6-hydroxy-7-methoxycoumarin derivatives (C29, C30, C39, C40, C41, C42, and C43) were cytotoxic to tumor cell fine HSC-2. However, C34 and C38 were relatively non-toxic to all cell lines used. It is suggested that the presence of polar substituents such as ester and alcohol group at the C-3 and/or C-4 position was unfavorable for cytotoxicity. This observation confirms the recent findings that 3,4-dimethyl- (C17) and 3,4-cyclopentano-6-hydroxy-7-methoxycoumarin (C22) showed marked cytotoxic effects [25]. However, it should be noted that 4-methyl-6-hydroxy-... 

Irradiation of JV,A, iV-tributyl-JV-(4-methylene-7-methoxycoumarin)ammo-nium borates promotes electron transfer from the borate anion to the singlet excited state of the coumarin, and in acetonitrile separation of the radical pair is efficient. Measurements have shown that electron donors will quench the excited state of triplet methyl phenylglyoxylate in excess of three orders of magnitude more rapidly than will hydrogen donors." ... 

Sample preparation Perform all operations with the exclusion of light. Evaporate 240 jjiL derivatization solution into a vial, add 400 pL 50 mM pH 7.0 phosphate buffer, add 100 [xL plasma, add 10 (xL 46 jxg/mL undecylenic acid in MeCN, vortex for 5 s, heat at 70° for 40 min, add 500 jxL MeCN, centrifuge at 3000 g for 5 min, inject a 20 jxL aliquot. (Derivatization solution was 1.65 g Arkopal N-130 (a non-ionic surfactant, nonylphenol/13 unit chain polyoxyethylene) + 650 mg tetrahexylammonium bromide -I- 60 mg 4-bromo-methyl-7-methoxycoumarin in 20 mL acetone.)... 

Bromo-methyl-7-methoxycoumarin Br-Mmc Carboxyl, imide, phenol, thiol... 

Carbonyl azides react with alcoholic hydroxy compounds to form the corresponding urethanes. In the same manner, ferrocenoyl azide, and 3-fe-rrocenylpropionyl azide can derivatized, hydroxy-steroids and the resultant derivatives are determined electrochemically by LC with the detection limits at subpicomole levels. 2-[2-(Azidocarbonyl)ethyl]-3-methyl-1,4-naphthoquinone (AMQ) reacts with primary and secondary alcohols to produce carbamic acid derivatives and is used in LC with BCD and FL detections. 7-Methoxycoumarin-4-carbonyl azide (7-MC-4-CON3) and 3,4-dihydro-6,7-dimethoxy-4-methyl-3-oxoquinoxaline-2-carbonyl azide (DMEQ-CON3) are also applied to LC with FL detection as precolumn reagents. 

Dihydroxy-3- 3-methyl-2-butenyl)phenyI -7-hydroxy-5-methoxy-2H-l-benzopyran-2-one, 9C1. 3- 2,4-Dihydroxy-3-prenylphenyl)-7-hydroxy-5-methoxycoumarin [155023-53-3]... 

Hydroxy-6-methoxycoumarin. Scopoletin. Aesculetin 6-methyl ether. Chrysatropic acid. Gelseminic acid, p-Methylaesculetin... 

FIGURE 2.1 Reagents for introducing a fluorophore into compounds with a complementary reactive functional group. Reagents 1 = dansyl chloride 2 = dabsyl chloride 3 = dansyl hydrazine 4 = fluorescamine 5 = 2,4-dihydro-6,7-dimethoxy-4-methyl-3-oxo-quinoxaline-2-carbonyl azide 6 = o-phthalaldehyde 7 = fluorenyhnethyloxycarbonyl chloride 8 — 4-bromome iyl-7-methoxycoumarin and 9 = 4-chloro-7-nitrobenzofurazan. 

---