Aromatic fluorine compounds. X. The 2,3- and 2,6-difluoropyridines
The preparation of difluoropyridines by the Schiemann reaction was investigated. 2-Amino-6-fluoropyridine (IIIa), necessary for the synthesis of 2,6-difluoropyridine (IVa) by the Schiemann reaction, was conveniently prepared by the Curtius degradation of 6-fluoropicolinic hydrazide (IIa) and by the Hofmann reaction on 6-fluoropicolinamide (IId). Since an α-fluorine on a pyridine nucleus is preferentially replaced by hydrazine when it is either adjacent to or opposite a carbomethoxy group, the hydrazides necessary for the synthesis of 3-amino-2- and 6-fluoropyridine could not be prepared. These amines were prepared from the appropriate 2-fluoropyridinecarboxamide by the Hofmann reaction. The preparation of difluoropyridines was successful with two of the aminofluoropyridines and led to the following new compounds: 2,3-difluoro(IVb) and 2,6-difluoropyridine (IVa).
Citation Information
Publication Year | 1962 |
---|---|
Title | Aromatic fluorine compounds. X. The 2,3- and 2,6-difluoropyridines |
DOI | 10.1021/jo01058a050 |
Authors | G. C. Finger, L. D. Starr, A. Roe, W. J. Link |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Journal of Organic Chemistry |
Index ID | 70010794 |
Record Source | USGS Publications Warehouse |