2,3-Methylenedioxy-7,8,10,11-tetrahydro-9H-cyclohepta [a] naphthalen-9-oneの合成

抄録

For the purpose of obtaining the compound (V) containing a seven-membered heterocyclic ring by cyclization of the amino-alcohol (VIII), either the nitroalcohol (VII) or the cyanohydrin (X) was first treated with lithium aluminum hydride. The product thus obtained was found, however, to be the diol (IX) and not the expected aminoalcohol (VIII) which was finally obtained by catalytic hydrogenation of X, but could not be cyclized to the 2-benzazepine (XIII) by the Pictet-Spengler or the Bischler-Napieralski method.
Next, we turned to the synthesis of the tetralone (XV), which was expected to be converted into a 2-benzazepine derivative by the Schmidt reaction. For this purpose the nitrile (XVI) was treated with methyl magnesium iodide to give the methyl ketone (XVIII) which underwent smooth condensation with ethyl formate, yielding XX. Acetalization of XX with ethylene glycol, followed by treatment with sodium borohydride, and acetylation, afforded XXII which on treatment with acetic acid-hydrochloric acid gave, as a result of cyclization by the acid used to the dihydronaphthalene (XXIII) and simultaneous Wagner-Meerwein rearrangement, the cycloheptanaphthalene (XXIV), as shown by the infrared, ultraviolet, and NMR spectra, together with its analytical values.