Organic Syntheses, CV 5, 897
Submitted by Ernst Schmitz and Roland Ohme
1.
Checked by E. J. Corey and Richard Glass.
1. Procedure
A.
3,3-Pentamethylenediaziridine. A solution of
147 g. (1.5 moles) of cyclohexanone in
400 ml. of 15N aqueous ammonia (6.0 moles) in a
1-l. beaker is stirred mechanically and cooled to 0° with an ice-salt mixture. Maintaining the temperature of the solution between 0° and +10°,
124 g. (1.0 mole) of 90% hydroxylamine-O-sulfonic acid (Note
1) is added in portions of about 1 g. The addition requires about 1 hour, and the mixture is stirred for another hour at 0° and allowed to stand overnight at −15° in a refrigerator. The precipitated crystalline cake is filtered and pressed tight with a
glass stopper. The solid is washed with
50-ml. portions of ice-cold ether, toluene, and finally ether. There is obtained
110–115 g. of product which is 70–90% pure (Note
2) and (Note
3). The product is divided into two portions, each of which is boiled briefly with a
50-ml. portion of toluene; the solutions are decanted from small salt residues and cooled to 0° for 2 hours. The precipitates are filtered with suction and washed with
50 ml. of ice-cold petroleum ether. The combined yield of
3,3-pentamethylenediaziridine is
68–78 g. (
61–70%), m.p.
104–107°. The purity is 96–100% (Note
4).
B.
3,3-Pentamethylenediazirine.
Caution! See (Note 5). A solution of
34.0 g. (0.2 mole) of silver nitrate is 100 ml. of water is treated dropwise, with shaking, with
100 ml. of 2N sodium hydroxide. The precipitate is filtered with suction and washed thoroughly with water,
methanol, and lastly
ether. A mixture of
10.0 g. (0.089 mole) of 3,3-pentamethylenediaziridine (Note
5) and
220 ml. of ether is warmed, the resulting solution cooled to room temperature, and within a 5-minute period the
silver oxide prepared above is added in small portions, with shaking, to the cooled solution. During the addition the reaction mixture is cooled with tap water and then is shaken without cooling until an aliquot does not liberate
iodine from an acidified iodide solution; the reaction is normally complete in 30–60 minutes. The mixture is filtered through a fluted filter, the solid residue washed with a small volume of
ether, and the filtrate dried over
potassium carbonate. The
ether is distilled at a bath temperature of 45° through a
30-cm. Vigreux column. The last 20 ml. of the solvent is removed at a pressure of 30 mm. and a bath temperature of 10°. Using a protective shield, the residue is distilled at
33° (30 mm.) to yield
6.4–7.4 g. (
65–75%) of
3,3-pentamethylenediazirine. In order to prevent decomposition of the product on storage, it is diluted with ether and kept in a refrigerator.
2. Notes
1.
Hydroxylamine-O-sulfonic acid is prepared according to the method of Gösl and Meuwsen,
2 or of Matsuguma and Audrieth.
3 The material is available from Eastman Organic Chemicals.
Analysis of this substance, just prior to use, is carried out in the following manner. A sample is dissolved in water and treated with a solution of
potassium iodide in
2N sulfuric acid. After 5 minutes the solution is titrated with thiosulfate solution; near the end of the titration the solution is boiled to ensure completeness of
iodine liberation. Instead of the 90% product, a correspondingly greater amount of the 80% product can be employed.
3. The crude product is recrystallized without additional drying; it undergoes partial decomposition on standing.
4. If subsequent treatment is not to be performed within a few days, it is recommended that the preparation be recrystallized a second time to obtain a stable product. Smaller amounts can be advantageously purified by vacuum sublimation.
5. It is recommended that the dehydrogenation be done with small amounts if the dehydrogenation product is to be isolated. Although decomposition was never observed with the preceding procedure,
diazirines should be handled with caution. Explosions were reported when working with 3-methyldiazirine4 and 3-n-propyldiazirine4 as well as when overheating pentamethylenediazirine.5 Most of the reactions of diazirines, especially the reaction with Grignard compounds,
5 can be done without purification of the diazirine.
3. Discussion
Diazirines have been prepared by dehydrogenation of diaziridines with
mercuric oxide,
6 silver oxide,
5 or dichromate-sulfuric acid.
4 The present procedure corresponds to that of Schmitz and Ohme.
5 The procedure for the preparation of the
3,3-pentamethylenediaziridine has been reported by H. J. Abendroth.
7
4. Merits of the Preparation
Copyright © 1921-2002, Organic Syntheses, Inc. All Rights Reserved