The synthesis of a number of substituted 1 : 2 : 3 : 4-tetrahydro-l-0~0quinolizinium bromides is reported. When boiled in acetic anhydride these ketones were converted in high yield into the corresponding substituted quinolizinium salts. From the tricyclic ketones (XXVIII), (XXIX), and (XXX), by similar treatment, the three benzoquinolizinium compounds were obtained.THE simple quinolizinium salts (I; X = I, ClO,, and picrate) were first obtained by Boekelheide and Gall,l by dehydrogenation of the dihydroquinolizinium iodide (11). This method has also been successfully applied to the synthesis of 4-methylquinolizinium saIts (XXIV) but has failed to give 4 : 6-dimethylquinolizinium salts.3 A second synthesis was reported by Richards and Stevens,* who have extended it subsequently to the preparation of a number of alkyl-and aryl-quinolizinium compound^.^ More recently, Nesmeyanov and Rybynskaia have described a synthesis which is specific for the preparation of 2-substituted quinolizinium salts6In a preliminary communication 7 we recorded the conversion of 1 : 2 : 3 : Ptetrahydro-l-oxoquinolizinium bromide 8 (111) into a quinolizinium salt, isolated as quinolizinium picrate (I; X = picrate), by treatment with boiling acetic anhydride containing a drop of sulphuric acid. We now record improvements in this synthesis, together with

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The synthesis of ( Z ) -and (€)-1 -azido-l,4-diphenylbut-l -ene (6a and b) is described, and their thermal decomposition. The synthesis of 5H-pyrrolo[l,2-a]azepine (2) and of 7H-pyrrolo[l,2-a]azepin-7-one (3) via the common dihydroazepinone intermediate (1 1 ) is also described.

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