Trimethyl-1,2-dioxetane

Chemiluminescence has been observed from chelate complexes of Eu ". For the case of the complex Eu(dbm)3(pyridine), the Do excited state can be populated by energy transfer from the electrogenerated singlet state exciplex BF /TPTA (where BP is benzophenone and TPTA is tri-p-tolylamine). A similar chemiluminescent system has been observed in the thermal decomposition of trimethyl-1,2-dioxetane to a triplet excited state in the presence of Eu(Ha)3(phen). The major fraction of the emission is observed from the Do state of Eu ", which is populated by intermolecular energy transfer. " ... 

A peculiar effect was observed in the decomposition of 19 a with anthracene as fluorescer when oxygen was carefully removed from the solutions an increase of the chemiluminescence decay rate and of the dioxetane cleavage resulted. It was suggested that this was due to a catalytic effect of triplet anthracene (formed by energy transfer from triplet formate) on the decomposition of the dioxetane. When oxygen is present, triplet anthracene is quenched. Whether such a catalytic effect of triplet anthracene or similar compounds on dioxetane cleavage actually exists has not yet been fully established positive effects were observed by M. M. Rauhut and coworkers 24> in oxalate chemiluminescence and by S. Mazur and C. S. Foote 80> in the chemiluminescent decomposition of tetramethoxy-dioxetane, where zinc tetraphenylporphy-rin seems to exert a catalytic effect. However, the decomposition of trimethyl dioxetane exhibits no fluorescer catalysis 78h... 

Up to about 10 percent of crs-stilbene was obtained when trimethyl-dioxetane 129 was decomposed in the presence of trans-stilbene 182) the electronic excitation energy of the excited carbonyl compounds formed in the cleavage of 129 (see Section V.) was transferred to trans-stilbene, so effecting the photochemical trans-cis isomerization. When bis (2.4-dinitrophenyl) oxalate reacted with hydrogen peroxide (see Section V. C. in the presence of o-tolyl-propane-1.2-dione 130, 2-methyl-2-... 

Dioxetan 3-Ethoxymethyl-3,4,4-trimethyl-E13/l,419(OH - OR) Ethan 1 -Ethoxy-1 -(2-methyl-propanoyloxy)- E14a/1, 326 (Enol-ether + R-COOH)... 

Cyclopropan l-(4-Methyl-phenyl-sulfonyl)- , 2,3-trimethoxy- E19b, 1732 f. (Carben + En) 1,2-Dioxetan 3-(4-Methyl-benzol-sulfonyloxy-methyl)-3,4,4-trimethyl- El3/1, 420 (OH - ... 

Serendipity, insight, and keen observation power were the ingredients of success in the preparation, isolation, and characterization of the first stable 1,2-dioxetane, namely, the trimethyl derivative (2) obtained in the base-catalyzed dehydrobromi-nation of 3-bromo-2-hydroperoxy-2-methylbutane (Eq. 5). Since then, well over a hundred 1,2-dioxetanes have been documented in the organic literature, most as transient intermediates and a good number (Table 1) as stable, isolable substances. 

Fig. 31. Thermal decomposition of the cyclic peroxide, 3,3,4-trimethyl-l,2-dioxetane, to give chemiluminescence.

Adam, W., Beinhauer, A., Fisher, R., and Hauer, H., A psoralen-substituted dioxetane as DNA intercalator for photogenotoxic studies. Angew. Chem., Int. Ed. Engl. 26, 796-797 (1987). Adam, W., Bhushan, V., Fuchs, R., and Kirchgassner, U., Functionalized 1,2-dioxetanes as potential phototherapeutic agents. The synthesis of carboxylate, carbonate, carbamate, and ether derivatives of 3- (hydroxymethyl)-3,4,4-Trimethyl-l,2-dioxetane. J. Org. Chem. 52, 3059-3062 (1987). 

Luminescence due to the decomposition of tetramethyl-1,2-dioxetane in benzene yielded a maximum value for wavelength of 430-440 mvi. This is similar to the spectrum of luminescence obtained by Kopecky (1969) for the thermal decomposition of 3,3,4-trimethyl-l,2-dioxetane with a maximum emission of 430-440 mji. Decomposition of these transient 1,2-dioxetanes form the electronically excited carbonyl compounds acetone and acetone/acetaldehyde, respectively. By excitation of acetone and acetaldehyde either singly, or as a 50% mixture of each with O2 generated from KO2, we obtained identical photon interference data placing the maximum emission around 435 my. 

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