The Formation of 3-Substituted Pyridines from Pyrrole¹

The Reimer-Tiemann Reaction.

“…It is perhaps significant that a combination of (1) high molecular weight, (2) structure, and (8) solubility inhibits side-reactions (formation of leucaurins, cyclohexadienones, and orthoformic esters). Hydroxy aldehydes obtained from phenols substituted with carboxy and sulfonic acid groups S. Phenols carrying carboxyl and sulfonic acid groups…”

“…Ring-expansion products (table 10) In 1881 Ciamician (35) observed and subsequently proved that the potassium salt of pyrrole, when heated with chloroform or bromoform in ether, furnished a jS-halopyridine. o -w• CT NT K (9%) Subsequent investigators (2,34,35,36,89,104) found that even under normal (aqueous) Reimer-Tiemann reaction conditions, ring-expansion products could be isolated in addition to normal products. In 1950 Alexander (2), investigating the reaction in some detail, confirmed the findings of earlier workers but was unable to improve the low (1-25 per cent) yields of this conversion.…”

“…Phenylpyridine is obtained in 1 per cent yield from pyrrole and a benzal halide(2,34,36).In1955 Parham and Reiff (97) treated the sodium salt of indene with chloroform, using indene as the i v i d u a l n o t d i r e c t l y a s s o c i a t e d w i t h s c i t e i s p r o h i b i t e d .…”

The brief career of a prolific, pioneering physical organic chemist, Elliot Ritchie Alexander, Jr.

“…Besides continuing investigations into sulfonation (7,8) nois involved the deamination of arenediazonium salts in the presence of deuterated acid (JO). In the following scant four years he published papers on deamination (fi), the Leuckart Reaction (12), reductive amination (13), the Mannich Reaction (14), hydrogenolysis (15), dibenzoylfurazane oxide formation ( 16), a pyrrole-to-pyridine transformation (17), and an improved method for the synthesis of ethyl 2,4-dimethyl-3-furoate (18). Various investigations into the chemistry of acetals and ortho esters and their interconversions led to five publications (19)(20)(21)(22)(23).…”