Abstract
5,6,8,9-Tetrahydrodibenzo[
c
,
h
]xanthylium salts (
13
) react with amines to yield the corresponding tetrahydroacridinium salts (
14
) which are reduced by NaBH
4
to hexahydroacridines (
15
). The
N
-alkylhexahydroacridines undergo thermolysis at
ca.
160 °C and the
N
-aryl analogues at > 250 °C to give alkanes and arenes. The
N
-alkyltetrahydroacridinium salts (
14
) and their 7-phenyl analogues (
12
) react at
ca.
130 °C with 1,5-diazabicyclo[4.3.0]non-5-ene to give the corresponding alkanes in good yield.