4-Methyl-7-methoxycoumarin esters

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... 

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-... 

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]. 

---