1031. The reaction of nicotinic acid 1-oxide and 3-picoline 1-oxide with acetic anhydride

Abstract

Nicotinic acid 1-oxide reacts with acetic anhydride to give as principal product 2-acetylnicotinic acid l-oxide ; 2-hydroxynicotinic acid and 6-hydroxynicotinic acid are by-products. Nicotinic acid l-oxide and propionic anhydride give a neutral diketone (111), together with 2-and 6-hydroxynicotinic acid ; 2-propionylnicotinic acid 1-oxide is formed when reaction times are very short. Isonicotinic acid l-oxide and cinchomeronic acid l-oxide are deoxygenated by acetic anhydride. 3-Picoline l-oxide and acetic anhydride give 3-methyl-2-pyridone, 5-methyl-2-pyridone, and 3-methyl-l-(5-methyl-2-pyridyl) -2-pyridone. Under the same conditions S-hydroxypyridine 1-oxide gives 2,3-dihydroxypyridine as the only product isolated. The mechanisms of these reactions are briefly discussed.ALTHOUGH the rearrangements of pyridine N-oxides have been studied extensively in recent years, there appears to be no record of the behaviour of nicotinic acid 1-oxide towards acetic anhydride. The available evidence relating to the rearrangements of 3-substituted pyridine N-oxides (e.g. , the reaction of nicotinic acid l-oxide with phosphorus pentachloride and phosphorus oxychloride,l and the reaction of 3-picoline 1-oxide with acetic anhydride 2, led us, ab initio, to expect a preponderance of 2-hydroxynicotinic acid in the product. When nicotinic acid I-oxide was boiled with acetic anhydride for six hours N $3cc; ' , , J CHMe 2-acetylnicotinic acid l-oxide (I) (25-30y0), 2-hydroxynicotinic acid (lo%), and 6-hydroxynicotinic acid (3%) were obtained.2-Acetylnicotinic acid l-oxide readily gave the haloform reaction ; the major product * A preliminary account of part of this work has been reported in Clzem. and Ind., 1960, 402.

The Rearrangement of 2,4-Dimethylthiazole 3-Oxide With Acetic Anhydride

“…The usual as well as a wide variation of oxidation conditions gave a low yield of the known 4-methylthiazole 3-oxide (3). Rearrangement in acetic anhydride produced a mixture of products containing both 4-acetoxymethylthiazole and 2-acetoxy-4-methylthiazole.…”

Controlled Oxygen Release from Pyridone Endoperoxides Promotes Cell Survival under Anoxic Conditions

“…3,5-Lutidine 7 was converted with meta-chloroperbenzoic acid into its corresponding N-oxide, which was first treated with acetic acid anhydride and then with water at elevated temperature giving 3,5-dimethyl-2-pyridone 8. 41 The series of 2-pyridones was N-alkylated with 2-[2-(2methoxyethoxy)ethoxy]ethyl 2-bromoacetate. 42 Careful adjustment of the reaction conditions for each 2-pyridone was necessary to control N-versus O-alkylation.…”

“…3,5-Lutidine 7 was converted with meta -chloroperbenzoic acid into its corresponding N -oxide, which was first treated with acetic acid anhydride and then with water at elevated temperature giving 3,5-dimethyl-2-pyridone 8 …”

Pyridine (Continued) the Properties of Functional Groups

“…- (58) - (59) Ar ~2-CsHsN u~~ ~sN UN~~ Oxidations-4-Vinylpyridine can be oxidized to the glycol by cold permanganate solution333. When the acetic anhydride reaction (p. 340) is applied to 2-styryl-and 2-propenyl-pyridine 1-oxides, some of the glycol is produced in each case334.…”