Experiments towards the Preparation of 6‐Hydroxy‐,6‐Methoxy‐, and 6‐(hydroxyphenyl)‐2,3‐dihydro‐1,4‐diazepinium Salts and 1,2‐Dihydro‐5‐(Hydroxyphenyl)‐2‐oxopyrimidinium Salts

The preparation of a number of 2,3‐dihydro‐6‐(hydroxyphenyl)‐1,4‐diazepinium salts ( 11c – f ) and of 1,2‐dihydro‐5‐(hydroxyphenyl)‐2‐oxopyrimidinium salts ( 17a, b ) from 3‐(hydroxyphenyl)vinamidinium salts ( 10b, c ) is described. Attempted preparation of a 3‐(2‐hydroxyphenyl)vinamidinium salt gave instead a mixture of formyl‐substituted benzofuranones ( 15 and 16 ). Attempted preparation of 2,3‐dihydro‐6‐hydroxy‐1,4‐diazepinium salts ( 1a – c ) provided products other than diazepinium salts, but 2,3‐dihydro‐6‐methoxy‐1,4‐diazepinium salts ( 7a, b ) were prepared.