OXALYL BROMIDE

1

Oxalyl Bromide

O

Br

Br

O

[15219-34-8]

C

2

Br

2

O

2

(MW 215.82)

InChI = 1/C2Br2O2/c3-1(5)2(4)6
InChIKey = JAZLVNXWYDFQFE-UHFFFAOYAO

(reactive acid halide;

1

heterocycle synthesis

2

)

Physical Data:

bp 16–17

◦

C/10 mmHg; d 2.30 g cm

−3

.

Form Supplied in:

liquid or solution in CH

2

Cl

2

; commercially

available.

Preparative Methods:

originally prepared by Staudinger in 1913

by treating Oxalyl Chloride with HBr;

3

a more recent report

describes a convenient alternative using Bromotrimethylsilane
which provides the reagent in 85% yield.

4

Handling, Storage, and Precautions:

corrosive; lachrymator. Use

in a fume hood.

Brominations. Oxalyl bromide is useful for the preparation

of acid bromides from carboxylic acids or salts.

5

These acid bro-

mides are quite reactive and will often acylate nucleophiles under
milder conditions than those required for the corresponding acid
chlorides.

1

Oxalyl bromide has found use for the preparation of a number

of brominated heterocycles. Reaction of oxalyl bromide with α-
amino- or α-hydroxynitriles yields substituted 2(1H)-pyrazinones
(eq 1)

2a

and 2H-1,4-oxazin-2-ones (eq 2),

2b

respectively.

MeH

2

N

CN

+

N

N

O

Br

Br

Me

(COBr)

2

(1)

80–100 °C

49%

HO

CN

N

O

O

Br

Br

(COBr)

2

(2)

90 °C
25%

Reaction of cyanogen with oxalyl bromide affords the tetra-

bromopyrazine (1) in greater than 70% yield (eq 3).

6

A com-

pletely different product is obtained in this reaction when Oxalyl
Chloride is used.

Br

O

O

Br

Br

N

N

Br

Br

Br

NC CN

(3)

70–140 °C
Bu

4

N

+

Br

–

+

(1)

HBr
70%

1.

Dowd, P.; Garner, P.; Schappert, R.; Irngartinger, H.; Goldman, A., J. Org.
Chem. 1982

, 47, 4240.

2.

(a) Vekemans, J.; Pollers-Wieers, C.; Hoornaert, G., J. Heterocycl. Chem.
1983, 20, 919. (b) Meerpoel, L.; Hoornaert, G., Synthesis 1990, 905.

3.

Staudinger, H.; Anthes, H. B., Biochemistry 1913, 46, 1431.

4.

Schmidt, A. H.; Russ, M.; Grosse, D., Synthesis 1981, 216.

5.

Adams, R.; Ulich, L. H., J. Am. Chem. Soc. 1920, 42, 599.

6.

Sundermeyer, J.; Roesky, H. W., Angew. Chem., Int. Ed. Engl. 1988, 27,
1372.

Michael D. Ennis

The Upjohn Company, Kalamazoo, MI, USA

Avoid Skin Contact with All Reagents