Org. Synth. 1963, 43, 1
DOI: 10.15227/orgsyn.043.0001
1-AMINOPYRIDINIUM IODIDE
[Pyridinium, 1-amino-, iodide]
Submitted by R. Gösl and A. Meuwsen
1.
Checked by N. A. Fedoruk and V. Boekelheide.
1. Procedure
To a freshly prepared solution of 11.3 g. (0.10 mole) of hydroxylamine-O-sulfonic acid (Note 1) in 64 ml. of cold water there is added 24 ml. (24 g., 0.30 mole) of pyridine (Note 2). The mixture is heated at about 90° on a steam bath for 20 minutes. It is then cooled to room temperature with stirring, and 13.8 g. (0.10 mole) of potassium carbonate is added. The water and excess pyridine are removed from the mixture by heating it at 30–40° in a rotatory evaporator in conjunction with a water aspirator. The residue is treated with 120 ml. of ethanol, and the insoluble precipitate of potassium sulfate is removed by filtration.
Fourteen milliliters (22 g., 0.10 mole) of 57% hydriodic acid is added to the filtrate, and the resulting solution is stored at −20° for 1 hour (Note 3). The solid that separates is collected; weight 15.5–17.5 g. Recrystallization of this solid from about 100 ml. of absolute ethanol gives 14–16 g. (63–72%) of 1-aminopyridinium iodide as almost-white crystals, m.p. 160–162° (Note 4).
2. Notes
1.
Hydroxylamine-O-sulfonic acid may be purchased from Ventron Corporation or prepared according to the directions in
Inorganic Syntheses.2Because aqueous solutions of hydroxylamine-O-sulfonic acid are not very stable, it is very important to use freshly prepared solutions. The purity of hydroxylamine-O-sulfonic acid should be checked by iodometric titration. If it is less than 85–90% pure, the yield of 1-aminopyridinium iodide will suffer. The acid can be purified by dissolving it in an equal weight of water and then precipitating it by stirring 7 volumes of acetic acid into the solution.
2.
The
pyridine was distilled before use. When the conversion is carried out in the presence of
potassium carbonate using an equimolar amount of
pyridine instead of an excess, the yields obtained are
20–30% lower.
33.
The temperature is kept at −20° or lower by a
bath of dry ice and methanol. If the temperature rises above −20°, an appreciable quantity of
1-aminopyridinium iodide may redissolve and be lost.
4.
The melting point recorded for
1-aminopyridinium iodide is
161–162°.
3
3. Discussion
The formation of
1-aminopyridinium chloride has been accomplished by the acid hydrolysis of
N-(p-acetaminobenzenesulfonimido) pyridine.
4 Also, the rearrangement of a substituted diazepine has been observed to give a 1-aminopyridine derivative.
5 The present procedure is an adaptation of that described by Gösl and Meuwsen.
34. Merits of the Preparation
This procedure is a convenient and general method for preparing asymmetrically substituted hydrazines.
3 This is illustrated by the following examples reported by the submitters
3 (% yields in parentheses):
methylamine to
methylhydrazinium hydrogen sulfate (
49–53%);
ethylamine to
ethylhydrazinium hydrogen oxalate (
51%);
butylamine to
butylhydrazinium hydrogen sulfate (
49–56%);
piperidine to
1-aminopiperidinium hydrogen oxalate (
32%);
dibutylamine to
1,1-dibutylhydrazinium hydrogen oxalate (
34%);
trimethylamine to
1,1,1-trimethylhydrazinium hydrogen oxalate (
79–85%);
2-picoline to
1-amino-2-methylpyridinium iodide (
57%);
2,4-lutidine to
1-amino-2,4-dimethylpyridinium iodide (
40%);
2,6-lutidine to
1-amino-2,6-dimethylpyridinium iodide (
34%);
2,4,6-collidine to
1-amino-2,4,6-trimethylpyridinium iodide (
30%); and
quinoline to
1-aminoquinolinium iodide (
32%).
Primary, secondary, and tertiary amines can be aminated by chloramine also, but pyridine nitrogens have been aminated only by hydroxylamine-O-sulfonic acid.
It has been shown that, on treatment with base,
1-aminopyridinium iodide undergoes 1,3-dipolar addition with
ethyl propiolate or
dimethyl acetylenedicarboxylate; thus the N-aminoheterocycles may serve as convenient starting materials for the synthesis of a variety of unusual fused heterocycles.
6
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
N-(p-acetaminobenzenesulfonimido) pyridine
ethanol (64-17-5)
potassium carbonate (584-08-7)
acetic acid (64-19-7)
potassium sulfate (37222-66-5)
pyridine (110-86-1)
piperidine (110-89-4)
hydriodic acid (10034-85-2)
Quinoline (91-22-5)
2,6-Lutidine (108-48-5)
Butylamine (109-73-9)
methylamine (74-89-5)
Trimethylamine (75-50-3)
chloramine (10599-90-3)
2,4,6-collidine (108-75-8)
2-picoline (109-06-8)
Dimethyl acetylenedicarboxylate (762-42-5)
ethylamine (75-04-7)
1-Aminopyridinium iodide,
Pyridinium, 1-amino-, iodide (6295-87-0)
Hydroxylamine-O-sulfonic acid (2950-43-8)
1-aminopyridinium chloride
ethylhydrazinium hydrogen oxalate
butylhydrazinium hydrogen sulfate
1-aminopiperidinium hydrogen oxalate
Dibutylamine (111-92-2)
1,1-dibutylhydrazinium hydrogen oxalate
1,1,1-trimethylhydrazinium hydrogen oxalate
1-amino-2-methylpyridinium iodide
2,4-lutidine (108-47-4)
1-amino-2,4-dimethylpyridinium iodide
1-amino-2,6-dimethylpyridinium iodide
1-amino-2,4,6-trimethylpyridinium iodide
1-aminoquinolinium iodide
ethyl propiolate (623-47-2)
methylhydrazinium hydrogen sulfate
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