... Tetrahedron: Asymmetry. Volume 9, Issue 16, 21 August 1998, Pages 2791–2794. ... 3. Treatment of 2-chloro-5-aminopyridine 5 with boron trifluoride etherate and t-butylnitrite generated the diazonium salt which was decomposed in acetic anhydride [9]to give 2-chloro-5 ...