Process for making CGRP receptor antagonists

A process for making a compound of Formula I

• or a pharmaceutically acceptable salt thereof, wherein:
• X is —C(R3)═ or N—, wherein R3 is hydrogen, F or CN;
• Y is CH or N;
• R1 is:
• C1-4alkyl, cyclopropylmethyl, cyclobutylmethyl, or [1-(trifluoromethyl)cyclopropyl]methyl, each of which may optionally be substituted with one or more substituents as allowed by valence, which are independently:
• F or hydroxy;
• and
• R2 is 0 to 5 substituents which are independently for each occurrence:
• methyl, F, Cl, or Br;
• said process comprising crystallizing the compound of Formula A
• in the presence of an arylaldehyde derivative and a first acid in a first organic solvent to yield the compound of Formula B
• optionally as a salt, and coupling the compound of Formula B with a compound of Formula C
• or a salt thereof, under conditions for an amide bond formation between an acid and an amine to yield a compound of Formula I.