Organic Syntheses, Coll. Vol. 3, p.351 (1955); Vol. 24, p.53 (1944).
Submitted by Lee Irvin Smith and Kenneth L. Howard.
Checked by H. R. Snyder, R. L. Rowland, and H. J. Sampson, Jr..
1. Procedure
In a pressure bottle are placed
19.6 g. (0.1 mole) of benzophenone hydrazone (Note 1),
22 g. (0.1 mole) of yellow oxide of mercury, and
100 ml. of petroleum ether (b.p.
30–60°). The bottle is closed, wrapped in a wet towel, and shaken mechanically at room temperature for 6 hours. The mixture is then filtered to remove
mercury and any
benzophenone azine (Note 2), and the filtrate is evaporated to dryness under reduced pressure at room temperature. The crystalline residue of
diphenyldiazomethane melts when its temperature reaches that of the room
(Note 3), but it is difficult to purify and this product is pure enough for all practical purposes. The material weighs
17.3–18.6 g. (
89–96%). The product should be used immediately
(Note 4).
2. Notes
2.
This ketazine is insoluble in
petroleum ether.
3.
The reported melting point of
diphenyldiazomethane is
29–30°, but this melting point is shown only after the substance has been recrystallized from
petroleum ether.
4.
On standing,
diphenyldiazomethane decomposes to yield
benzophenone azine. In one of the checkers' runs the product was stored at room temperature; after 2 days, crystals of the azine were visible. The product at this stage was assayed by treatment with
benzoic acid; addition of 6.8 g. of the diazo compound in a thin stream to a solution of
17 g. of benzoic acid in 90 ml. of ether, and, after 30 minutes, extraction of the excess
benzoic acid with dilute
sodium hydroxide followed by distillation of the
ether gave
7.4 g. (
75%) of crude
benzohydryl benzoate melting at
83–85°. In the same procedure the freshly prepared diazo compound gave a quantitative yield of the crude ester.
3. Discussion
This preparation is referenced from:
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved
