II.* MASS SPECTROMETRY By D. G. HAWTHORN,E~$ and
Q. N. PORTER^ [Manzlscript received March
6, 19671 The high-resolution mass
spectra of some derivatives of naphtho[l,S-be]- thiophen have been
analysed. The base peak in the spectra is usually the naphtho- [1,8-bclthienylium cation
(mle 171) or one of its substitution products; this emphasizes the stability of
this species. Structures are suggested for most of the other ions observed in the
spectra. INTRODUUTION In Part I, which dealt with
the synthesis of naphtho[l,8-bclthiophen derivatives, the mass spectra of the
2-methyl-2H- (I; R = CH,) and 2-phenyl-2H- (I; R = Ph) compounds were briefly
described. It was suggested that in each case the cleavage shown gave the ion of mle
171, for which the naphthothienylium cation structure ac was proposed. (1) ac; m/e 171 In this paper we present a
complete analysis of the spectra of these compounds, and of some related
naphtho[l,8-bclthiophen derivatives. For reasons outlined in
Part I of this series, it is not possible to write structures for fragment ions from
aromatic and heteroaromatic molecules with the confidence with which this can be done
for many less-aromatic systems. In writing ionic structures to formalize the
observed spectra, the following principles have been used: (i) Where the formation of
an odd-electron system is involved, the ion is, if possible, written as a
radical cation derivable from an aromatic system. There is * Part I, Aust. J. Chem.,
1966, 19, 1909. t Department of Organic
Chemistry, University of Melbourne, Vic. 3052. $ Present Address: Division
of Applied Mineralogy, CSIRO Chemical Research Labora- tories, Melbourne, Vic.
3001. Aust. J. Chem., 1968, 21,
171-83
Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides
