Patent ID: 8809024

Claim:
A method for making a compound of the structure or a salt thereof, the method comprising: treating (1S,3S,5S)-2-(tert-butoxycarbonyl)-2-azabicyclo[3.1.0]hexane-3-carboxylic acid first with an alkyl chloroformate or mesyl chloride in the presence of a base, and then with ammonia to form (1S,3S,5S)-tert-butyl 3-carbamoyl-2-azabicyclo[3.1.0]hexane-2-carboxylate; and deprotecting the (1S,3S,5S)-tert-butyl 3-carbamoyl-2-azabicyclo[3.1.0]hexane-2-carboxylate to form the compound or salt.