ISSN:
0170-2041
Keywords:
Dioxetanes
;
Furocoumarins
;
Furoquinolines
;
Naphthofurans
;
Photooxygenation
;
Singlet Oxygen
;
Salmonella typhimurium
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The low temperature photooxygenation of the furocoumarins 1a-e, the naphthofurans 1f-h, and the furoquinoline 1i afforded the corresponding dioxetanes 2 in good yields, except the linearly annulated naphthofuran 1f, which led exclusively to the allylic hydroperoxide 5f by ene reaction with singlet oxygen. The dioxetanes 2 were rigorously purified by means of low temperature silica gel chromatography and fully characterized. Thermolysis of the furocoumarin dioxetanes 2a-e led to the expected cleavage products 3a-e (acetyloxy- and acetyl-substituted coumarins), while the naphtho- and quino-linofuran dioxetanes 2g-i gave in addition to the cleavage products 3g-i also the spiroepoxides 4g-i. Intramolecular electron transfer from the aromatic moiety to the dioxetane ring, with subsequent cyclization of the radical-ion species and fragmentation is postulated as mechanism for the formation of this novel rearrangement product of dioxetanes. On heating in chloroform the spiroepoxides 4g,h rearranged into the 1,3-dioxole 6g, but heating of 4g in methanol gave the dioxine 7g by trapping of the dipolar intermediate. - The furocoumarin dioxetanes 2a,c,d showed high mutagenic activity in the Salmonella typhimurium strain TA 100 but not in the strain TA 2638. The naphtho- and quinolinofuran dioxetanes 2h,i and the spiroepoxides 4g,h were nonmutagenic in the TA 100 strain. Epoxide-like DNA damage appears to be responsible for the mutagenicity of the furocoumarin dioxetanes 2a,c,d.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.1990199001221
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