Pyridinium tribromide

Structural formula
General
Surname	Pyridinium tribromide
other names	Pyridine hydrobromide perbromide; Pyridine perbromide hydrobromide; Pyridinium bromide perbromide;
Molecular formula	C 5 H 6 Br 3 N
Brief description	red odorless solid
External identifiers / databases
EC number	254-446-8
ECHA InfoCard	100,049,479
PubChem	11983801
Wikidata	Q30693054
properties
Molar mass	319.82 g mol −1
Physical state	firmly
Melting point	130 ° C
solubility	soluble in methanol, acetic acid, ethanol, n-butanol and tetrahydrofuran; practically insoluble in water, carbon tetrachloride, ethyl bromide, benzene, toluene and ligroin;
safety instructions
GHS labeling of hazardous substances danger
H and P phrases	H: 314
	P: 280-305 + 351 + 338-310
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Pyridinium tribromide is a chemical compound of bromine from the group of pyridinium compounds .

Extraction and presentation

Pyridinium tribromide can be obtained by reacting pyridinium hydrobromide with bromine or thionyl bromide .

properties

Pyridinium tribromide is a crystalline red odorless solid that is practically insoluble in water.

use

Pyridinium tribromide is used as a bromination reagent for ketones , phenols and ethers . It has several advantages over elemental bromine, such as very precise weighing in small-scale reactions. An example of its application is the bromination of the 3-keto steroid 1 to form 2,4-dibromocholestanone ( 2 ):

Individual evidence

↑ ^a ^b Data sheet pyridinium bromide perbromide (PDF) from Merck , accessed on August 13, 2017.
↑ ^a ^b ^c ^d data sheet Pyridinium tribromide, technical grade, 90% from Sigma-Aldrich , accessed on August 13, 2017 ( PDF ).
↑ ^a ^b ^c ^d data sheet Pyridine hydrobromide perbromide, tech. 90% at AlfaAesar, accessed August 13, 2017 ( PDF )(JavaScript required) .
^ Houben-Weyl Methods of Organic Chemistry Vol. V / 4, 4th Edition: Bromine and Iodine Compounds . Georg Thieme Verlag, 2014, ISBN 978-3-13-180014-5 , p. 35 ( books.google.de ).
↑ Jürgen Falbe, Manfred Regitz: Römpp-Chemie-Lexikon . Thieme, Stuttgart 1992, ISBN 3-13-735009-3 , p. 3696-3697 .
↑ Carl Djerassi, Caesar R. Scholz: Brominations with Pyridine Hydrobromide Perbromide . In: Journal of the American Chemical Society . 70, No. 1, January 1948, pp. 417-418. doi : 10.1021 / ja01181a508 .
↑ Jonathan Clayden, Nick Greeves, Stuart Warren: Organic Chemistry . 2nd Edition. Springer Spectrum, Berlin Heidelberg 2013, ISBN 978-3-642-34715-3 , p. 802-804 .

[Merck-1] Data sheet pyridinium bromide perbromide (PDF) from Merck , accessed on August 13, 2017.

[Sigma-2] ta sheet Pyridinium tribromide, technical grade, 90% from Sigma-Aldrich , accessed on August 13, 2017 ( PDF ).

[Alfa-3] ta sheet Pyridine hydrobromide perbromide, tech. 90% at AlfaAesar, accessed August 13, 2017 ( PDF )(JavaScript required) .

[4] Houben-Weyl Methods of Organic Chemistry Vol. V / 4, 4th Edition: Bromine and Iodine Compounds . Georg Thieme Verlag, 2014, ISBN 978-3-13-180014-5 , p. 35 ( books.google.de ).

[Römpp-5] Jürgen Falbe, Manfred Regitz: Römpp-Chemie-Lexikon . Thieme, Stuttgart 1992, ISBN 3-13-735009-3 , p. 3696-3697 .

[Djerassi-6] Carl Djerassi, Caesar R. Scholz: Brominations with Pyridine Hydrobromide Perbromide . In: Journal of the American Chemical Society . 70, No. 1, January 1948, pp. 417-418. doi : 10.1021 / ja01181a508 .

[Clayden-7] Jonathan Clayden, Nick Greeves, Stuart Warren: Organic Chemistry . 2nd Edition. Springer Spectrum, Berlin Heidelberg 2013, ISBN 978-3-642-34715-3 , p. 802-804 .