3-picoline permanganate oxidation

Picolinic acid has been generally prepared by the permanganate oxidation of a-picoline and isolated through the copper salt.1-2 3-4 5 In one instance,6 it was isolated directly as in the present procedure. It has recently been secured by the hydrolysis of w-trichloropicoline.7... 

Picoline (as KMnOJ (as H2SO4) Nicotinic Acid Scheme 15.2 Permanganate oxidation of 3-picoline. 

Picoline is also efficiently oxidized to isonicotinic acid by the black manganese dioxide that is formed in some permanganate oxidations of organic substances.392... 

Oxidation of hydroxymethyl alkylpyridines with the HjOa/HOAc affords N-and C-oxidation products 2 ydroxymethyl-6-methylpyridine (X-210) yielded 6-inethylpicolinic acid-1-oxide (X-211) and 2-hydroxymethyl-6-methylpyri-dine-l-oxide (X-212). Similarly, 2,6-bis(hydroxymethyl)pyridine (X-213) yielded the expected pyridine-1-oxide (X-214) and a small amount of 6-hydroxymethyl-picolinic acid-l-oxide (X-215). On the other hand, permanganate oxidations lead... 

Kcolinic acid Is readily prepared by the oxidation of a-picoline with potassium permanganate ... 

Bipyridine was first prepared in 1888 by the dry distillation of the copper salt of picolinic acid. This method and modifications give low yields of 2,2 -bipyridine. Another old method Involves oxidation of 1,10-phenanthrbline (28) to 2,2 -bipyridine-3,3 -dicarboxylic acid (29) by alkaline permanganate, followed by decarboxylation. This... 

Nicotinic acid has been prepared by the oxidation of nicotine with nitric acid.1 It has also been prepared by the action of potassium permanganate upon /3-picoline, nicotine, lutidine, /3-phenyl pyridine, and /3-dipyridyl2 and by the action of chromic acid upon nicotine and /3-phenyl pyridinecarboxylic acid.3... 

Fischer attempted the bromination of apoharmine in dilute sulfuric acid at room temperature and obtained a tetrabromo compound, which he did not characterize further. Treatment of l-benzoyl-2,5-dimethyl-4-azaindole with bromine in acetic acid at 25° gave the 3-bromo-l-benzoyl compound in 60% yield. On oxidation with permanganate it gave the same picolinic acid obtained before. Alkaline hydrolysis gave 3-bromo-2,5-dimethyl-4-azaindole (90%), also obtained by direct bromination of 2,5-dimethyl-4-azaindole in 60 % yield. 

Niacin (also known as vitamin B ) and other oxygenated products of picolines, pyrimidines, quinolines, and pyrazines are of considerable value in pharmaceutical, agrochemical, and fine-chemical applications. Most these intermediates are usually produced using environmentally aggressive oxidizing agents such as chromic acid, permanganates, selenium dioxide (SeO ), and BnO +O and may involve two (or more) separate steps. 

Liquid-Phase Oxidation of 3-Picoline with Permanganate, Chromic Acid or Nitric Acid... 

The oxidation of picoline with permanganate or chromic acid suffers from the same drawback, albeit in a lesser form, as nicotine (Scheme 15.2). 

Isonicotinic and picolinic acid are similarly obtained from 4- and 2-picoline, respectively, by oxidation with permanganate,391 yields being 50- 60% and 50% (as hydrochloride), respectively. 

---