The chemical properties of ( I ) , X = 0, are also in accord with the proposed structure. Treatment of the compound with acids leads t o a-naphthol and other products; during chromatography on silica gel it isomerizes to l-benzoxcpin ( 4 ) [3], a yellow liquid, b.p. 101-102ยฐC/14 mm, ng = 1.6015 (yield up t o 77 %). The structure of the rearrangement product (4) is secured by its spectra and its catalytic hydrogenation t o yield the known tetrahydro-I-benzoxepin, m.p. 30 "C [4].
The aziridine (5), b.p. 76--77 "C/0.6 mm, required for the synthesis of the acetyliminobridged compound ( I ) , X = NCOCH3, was prepared from the nitrosochloride [2] of 1,4,5,8-tetrahydronaphthalene using the method of Cluss [5].
Bromination of the N-acetyl derivative of (5), m.p. 73--74 " C , gave the tetrabromide (6) as a n oil, which reacted with potassium t-butoxide in tetrahydrofuran at -15 " C t o form ( I ) , X = NCOCH3, as paleyellow crystals, m.p. 160-161 "C,
The main evidence for structure ( I ) , X = NCOCH3, is again given by the N M R spectrum of the compound; it exhibits an A2B2 system (8 protons) centred at 2.35 T and a CH3 singlet at 8.97 7. Further support for structure ( I ) , X = NCOCH3, is obtained from the ultraviolet spectrum, which has maxima at 252 (E =.57000), 299 (5500), 387 (300), 398 (500), and 408 rnv-( ) and agrees well with the ultraviolet spectra of ( I ) , X = CH2, and ( I ) '
[71.