The Preparation of N-Phenyl-1,2-dihydropyridine^1,2

Preparation, structure, and conformation in solution of diacetyl derivatives of 6,7-dimethyl-1,4-dihydroquinoxaline and of dihydropyridotriazines

“…These 6 and J values, which are close to those observed in pyridine (5), indicate that the pyri- dinic ring retains its aromatic character in 5, 9, 10, and 11; therefore these derivatives have structures of type 1 or 11. ' The resonances of H5, H7, and H8 move upfield in 6 and the vicinal coupling constant -'J7_, increases to 8 Hz, as previously observed in 1,4-dihydropyridines (6). Hence the pyridinic ring has lost its aromatic character in 6 and this compound has a structure of type I11 or 1V.…”

The Chemistry of Imines.

“…Aliphatic aldimines when heated and then hydrolyzed were found to have undergone aldol condensation reactions to give the a,@-unsaturated aldehydes (273). Aniline when reacted with butyraldehyde in the presence of acetic acid has been shown to give as the main product N-phenyl-3,5-diethyl-2-propyl-l,2-dihydropyridine (50,233). This reaction probably results from tautomerization and ring closure of the following aldol condensation product.…”

Mass spectrometric studies on 4‐aryl‐1‐cyclopropyl‐1,2‐dihydropyridinyl derivatives: an examination of a novel fragmentation pathway

“…An alternative approach to this system, involving treatment of 4‐phenyl‐ trans ‐1‐(2‐phenylcyclopropyl)pyridinium perchlorate ( 12 + ClO 4 − ) with NaBH 4 in methanolic KOH,21 gave the free base 6 in good yield (Scheme ). The 1 H and 13 C NMR spectra are fully consistent with the assigned structure.…”