Boron‐Nitrogen Compounds. 88 [1]. Boron Derivatives of Pyridylalkylamines

2‐Aminomethylpyridine and 2‐aminoethylpyridine, when reacted in a 1:2 molar ratio with trialkylboranes, form intermediates which on pyrolysis yield (2‐pyridylalkylamino)dialkylboranes, C 5 H 4 N2‐(CH 2 ) n NHBR 2 (n = 1 or 2; R = C 2 H 5 , n‐C 3 H 7 ). Nuclear magnetic resonance data show that if R = C 2 H 5 the compounds exist in an intramolecular coordinated bicyclic structure containing four‐coordinate boron. If R = C 3 H 7 , the species with n = 1 exists in both the noncoordinated (with trigonal boron) as well as the bicyclic coordinated form, but with n = 2 the compound exists exclusively in the open form with trigonal boron. — The two cited bases are similar in their reactivity with tetracoordinated boron derivatives. With trimethylamine‐borane, both amines undergo identical simultaneous base displacement and condensation to yield amine‐aminoboranes, 2‐[H 2 BNH(CH 2 ) n ]C 5 H 4 NBH 3 , while in the case of trimethylamine‐iodoborane base displacement and iodide ion displacement occurs with either pyridine derivative to yield a boronium(1+) salt.