Pyridines ANRORC reaction

The acid-catalyzed ot7, o-acylation of /3-oxoalkyl derivatives of 7t-excess aromatic heterocycles known as the Dorofeenko-Dulenko-Krivun reaction affords condensed pyrylium derivatives which are convenient precursors of the corresponding pyridines <2001CHE1310>. By this approach (Scheme 14), carbazole 100 is converted into carba-zolo[3,2-f]pyrylium 101, a new ISrt-electron heteroaromatic system, and 101 is readily transformed into isomer 102 of 6-methylellipticine via an Sn(ANRORC) reaction using ammonia. The yields for these transformations were not reported. 

The occurrence of this Sn(ANRORC) process has also been substantiated by N-labeUng experiments. Reaction of 3-aminocarbonyl-l-methylpyridinium salt (5, R = CONH2, Alkyl = CH3) with N-labeled liquid ammonia gives incorporation of the label into the pyridine ring (Scheme III.5) (84T433). 

Chichibabin and Ziegler reaction). In the presence of good leaving groups, diazines in general are more reactive in SnAt reactions than pyridine often substitution does not occur by simple addition/elimination processes, but by ANRORC mechanisms (cf. p 418). 

Breuker K, Van der Plas HC. Occurrence of an S m(ANRORC) mechanism in the chichibabin amination of 4-phenylpyrimidine. J Org Chem. 1979 44 4677-4680. Francis RF, Davis W, Wisener JT. Reaction intermediates in the alkylation of pyridine... 

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