Process for antiarrhythmic 1,3-diazabicyclo[4.4.0]dec-2-en-4-ones

A process for preparing a 1,3-diazabicyclo[4.4.0]dec-2-en-4-one of the formula ##STR20## or an isomer of a racemate thereof, wherein R is:

• (a) hydrogen
• (b) alkyl of 1 to 6 carbon atoms, inclusive;
• or
• (c) ##STR21## wherein each T is a substituent taken independently, selected from the group consisting of:
• (a) hydrogen
• (b) halogen;
• (c) alkyl of 1 to 6 carbon atoms, inclusive;
• (d) alkoxy of 1 to 6 carbon atoms, inclusive;
• or
• (e) phenyl;
• wherein each X is a substituent taken independently, selected from the group consisting of:
• (a) hydrogen;
• (b) halogen;
• (c) alkyl of 1 to 6 carbon atoms, inclusive;
• (d) alkoxy of 1 to 6 carbon atoms, inclusive;
• or
• (e) phenyl
• comprising
• (a) acylating a 2-piperidineacetamide of the formula ##STR22## or an isomer or a racemate thereof, wherein T and X are defined as above, to form a 1-acyl-2-piperidineacetamide of the formula ##STR23## or an isomer or a racemate thereof, wherein R, T, and X are defined as above;
• and
• (b) cyclizing the 1-acyl-2-piperidineacetamide with a strong base taken from the group consisting of alkali metal hydroxides, alkali metal alkoxides, alkaline earth hydroxides, and quaternary ammonium hydroxides in a polar organic solvent.