ISSN:
0170-2041
Keywords:
Pyrano[4,3-b]azepines
;
Azepines, 1,2-didehydro-
;
3-Azaheptafulvenes
;
Fulvenes, 3-azahepta-
;
Hetero-Diels-Alder reaction
;
Antiaromaticity
;
Photochemistry
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
3-Alkoxycarbonyl-1,2-didehydroazepines, generated by photolysis of alkyl 2-azidobenzoates, undergo a hetero-[4 + 2] cycloaddition (stepwise or concerted) with ketone-derived enol ethers to form intensely colored, paratropic 6,8-dialkoxy-8,9-dihydropyrano[4,3-b]azepines 5-7 which contain the unusual 3-azaheptafulvene partial structure. Other derivatives of 2-azidobenzoic acid as well as aldehyde-derived enol ethers, other classes of olefins, phenol ethers, and furans are unreactive although 2-methoxynaphthalene undergoes demethylation to produce methyl 2-(2-naphthyloxy)-3H-azepine-3-carboxylate (8). Acid-catalyzed hydrolysis of the title compounds produces 2-(acylmethylene)-2,3-dihydro-1H-azepine-3-carboxylates 9 and indoles 10, catalytic hydrogenation generates a tetrahydro derivative 11, and diastereomeric tricarbonyliron complexes 12 are formed with Fe2(CO)9 at the conjugated diene moiety. An intensely colored byproduct 13 of the photolysis reaction is identified as the first known derivative of 3,3′-diazaheptafulvalene.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199419941205
Permalink
