Carbon tetrachloride Coumarins

In order to determine the sensitivity of coumarin dimerization to heavy-atom perturbation, the direct photolysis was carried out in butyl chloride, propyl bromide, and ethyl iodide. Comparison of these results with those obtained in nonpolar solvents indicated that there was no significant change in the amount of the triplet-derived product (80) formed in the heavy-atom solvents as would be expected if heavy-atom perturbation were important.<90) More recent investigations,<93W however, of the formation of (79) in carbon tetrachloride indicate that halocarbon enhancement of the formation of this isomer exists. A direct measure of the intersystem quantum... 

Some glyoxal derivatives of coumarin have been shown to elicit a diuretic action [509—511]. This effect was demonstrated using coumarin-3-ylglyoxal (89) and 8-methoxycoumarin-3-ylglyoxal (90) in normal animals submitted to hydroxa-line load test, and in animals with experimentally impaired renal function brought about either by carbon tetrachloride poisoning or by aldosterone intervention. These coumarins were synthesised [512] and successfully applied in human therapy on renal function both in normal and pathological conditions. 

In its deprotonated form, cinnamic acid already presents some prerequisites of surfactants and is easily incorporated in reversed micelles, as demonstrated bySawaki and co-workers " " and others.Then-results support the view that increased local concentration and alignment can be achieved at micellar interfaces. Substantially higher conversion of cinnamate to its photodimers is observed upon irradiation of reversed micelles formed by laurylammonium or hexadecyltrimethylammonium cinnamate in carbon tetrachloride. The photoproducts are mainly the P- and 5-truxinates, consistent with the requirements imposed by the assembly for the formation of contact ion pairs. Unfortunately, these are also the main products observed by Reiser upon irradiation of ethyl cinnamate (albeit in different proportions). Interestingly, however, the observed dimer distribution varies as a function of added water that is proposed to He near the ion pair interface. Similar results were also obtained for indene-2-carboxylate and using sodium dodecyl sulfate microemulsions in water. " The photodimerization of coumarin in micelles has been investigated by Ramamurthy and co-workers. ... 

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