Acetone → hexahydro-3,3-dimethylimidazo(1,5-a)pyrazin-1(5H)-one

Reaction equation

[NH:1]1[CH2:6][CH2:5][NH:4][CH2:3][CH:2]1[C:7]([NH2:9])=[O:8].COCCO.[CH3:15][C:16](=O)[CH3:17]>>[CH3:15][C:16]1([CH3:17])[N:1]2[CH2:6][CH2:5][NH:4][CH2:3][CH:2]2[C:7](=[O:8])[NH:9]1

Participants

Reactant 3

HCID 180Acetone

HCID 80192-Methoxyethanol

HCID 3019914Piperazine-2-carboxamide

Product 1

HCID 14230278hexahydro-3,3-dimethylimidazo(1,5-a)pyrazin-1(5H)-oneYield 64%

Procedure

To a stirred and warm solution of 3 parts of 2-piperazinecarboxamide in 16 parts of 2-methoxyethanol were added 51.2 parts of 2-propanone. The whole was stirred and refluxed for 20 hours. The reaction mixture was evaporated. The solid residue was crystallized from acetonitrile, yielding 2.5 parts (64%) of hexahydro-3,3-dimethylimidazo[1,5-a]pyrazin-1(5H)-one; mp. 174.2° C. (intermediate 83).