Céline Damez, J. Labrosse, P. Lhoste
Nov 13, 2001
Citations
0
Influential Citations
4
Citations
Journal
ChemInform
Abstract
2H-1,5-Benzodioxepin-3(4H)-one (4a) is a key intermediate in the synthesis of analogs of 3,4-dihydro-2H-1,5benzodioxepine, which possess interesting biological properties. For example, members of this series constitute a unique class of -adrenergic stimulants and have also interesting bronchial dilator activity.1 The antifungal strobilurins I and K are also derivatives of 3,4-dihydro-2H-1,5benzodioxepine.2 These compounds have been obtained in very low yields by condensation of benzene-1,2-diol (1a) and 1,3-dichloro-2-hydroxypropane followed by oxidation with KMnO4 3 or by an allylation-epoxidation-cyclization-oxidation sequence.2 An alternative synthesis started with the condensation of benzene-1,2-diol (1a) with ethyl bromoacetate. Dieckmann cyclization of the obtained diester with sodium tert-butoxide yielded 2H1,5-benzodioxepin-3(4H)-one (4a).4 In another case, 6methoxy-3-oxo-2H-[1,5]-benzodioxepine was obtained by Thorpe cyclization of 1,2-bis(cyanomethoxy)benzene, affording an enaminonitrile which was easily hydrolyzed to the ketone 4a.1