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Pyridines Reimer-Tiemann reaction

Pyrrolo[2,3-6]pyridine, 2-methyl-Reimer-Tiemann reaction, 4, 508 Pyrrolo[2,3-6]pyridine, 4-methyl-hydrogen exchange, 4, 502 reaction with aldehydes, 4, 503 reaction with benzaldehyde, 4, 511... [Pg.822]

Methylpyrrolo(2,3-6]pyridine reacts with dichlorocarbene (Reimer-Tiemann reaction) to give the aldehyde (51) with no trace of a ring-expanded product (68AHC(9)27). On the other hand, the 2-phenyl compound gives the chloropyridine (52) and no aldehyde... [Pg.508]

Under the conditions of the Reimer-Tiemann reaction, 2-methyl-1 //-pyrrolo[2,3-/>]pyridine (57) gave the aldehyde (58) without any ring-expanded products (Equation (9)) <68AHC(9)27>. [Pg.200]

Pyrrolenines, intermediates in Reimer-Tiemann reaction of pyrroles, 72 pyridines from, 72 ring expansion of, 72 structures of, 72 3H-Pyrrolo[2,3-c]quinoline, 93 Pyrroloquinolones, 169... [Pg.216]

Methylpyrroles have been converted into pyridines by hydrochloric acid under severe conditions, and also by pyrolysis (p. 109). The formation of a 3-chloropyridine derivative from a pyrrole under Reimer-Tiemann conditions has been mentioned (p. 63). This type of reaction was discovered by Ciamician and Dennstedt treated pyrrole with chloroform in ether and isolated a small yield of 3-chloropyridine. Subsequently, similar reactions were realized with bromoform, carbon tetrachloride, methylene iodide and benzal chloride. Those of several of these reagents with lithium pyrrole in ether and sodium pyrrole under various conditions have been compared. The yields of pyridine derivatives were always low. In submitting 2,5-dimethylpyrrole to the Reimer-Tiemann reaction, Plancher and Ponti23 isolated a pyrrolenine (7). This and its analogues are not intermediates in the conversion of pyrroles into 3-chloropyridines. The idea that dichlorocarbene is the active reagent in reactions using chloroform is supported by recent work 22 ... [Pg.88]

The idea that dichlorocarbene is an intermediate in the basic hydrolysis of chloroform is now one hundred years old. It was first suggested by Geuther in 1862 to explain the formation of carbon monoxide, in addition to formate ions, in the reaction of chloroform (and similarly, bromoform) with alkali. At the end of the last century Nef interpreted several well-known reactions involving chloroform and a base in terms of the intermediate formation of dichlorocarbene. These reactions included the ring expansion of pyrroles to pyridines and of indoles to quinolines, as well as the Hofmann carbylamine test for primary amines and the Reimer-Tiemann formylation of phenols. [Pg.58]


See other pages where Pyridines Reimer-Tiemann reaction is mentioned: [Pg.1021]    [Pg.646]   
See also in sourсe #XX -- [ Pg.773 ]

See also in sourсe #XX -- [ Pg.773 ]

See also in sourсe #XX -- [ Pg.773 ]




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