4-bromopyrocatechol

Structural formula
General
Surname	4-bromopyrocatechol
other names	4-bromobenzene-1,2-diol 4-bromo-1,2-dihydroxybenzene
Molecular formula	C 6 H 5 BrO 2
External identifiers / databases
CAS number 17345-77-6 EC number 241-370-5 ECHA InfoCard 100,037,593 PubChem 28487 ChemSpider 26503 Wikidata Q229933
properties
Molar mass	189.01 g mol −1
Physical state	firmly
Melting point	87 ° C
pK s value	pK s 1  = 8.7 pK s 2  = 12.4
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319-335 P: 280-302 + 352-261
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

4-bromopyrocatechol is a chemical compound that belongs to the group of phenols . Along with 3-bromopyrocatechol, it is one of the two positionally isomeric monobromo derivatives of catechol (1,2-hydroxybenzene).

presentation

4-Bromo catechol can be made by bromination of catechol with pyridine dibromide bromohydrate in glacial acetic acid .

Analytical evidence

For qualitative analytical proof, the bromination with potassium bromide and bromine produces the tetrabromo derivative , which has a melting point of 192 ° C.

Derivatives

The methyl ethers of 4-bromopyrocatechol are listed in the table below:

Methyl ether of 4-bromopyrocatechol
Names	5-bromo-2-methoxyphenol 5-bromoguaiacol	4-bromo-2-methoxyphenol 4-bromoguaiacol	4-Bromo-1,2-Dimethoxybenzene 4-Bromveratrol	5-Bromo-1,3-benzodioxole 4-Bromo-1,2- (methylenedioxy) benzene
Structural formula
CAS number	37942-01-1	7368-78-7	2859-78-1	2635-13-4
Molecular formula	C 7 H 7 O 2 Br		C 8 H 9 O 2 Br	C 7 H 8 O 2 Br
Molar mass	203.0 g mol −1		217.0 g mol −1	201.0 g mol −1
Physical state	firmly			liquid
Melting point	65 ° C	46 ° C
boiling point	150 ° C (20 mbar)	181–182 ° C (60 mbar)	255–256 ° C 157–158 ° C (30 mbar)	226–228 ° C 103–107 ° C (10 mbar)

The esterification with acetic anhydride produces the diacetate (CAS number: 66373-95-3), which has a melting point of 109 ° C.

Individual evidence

1. ↑ ^{a b c d e} Dictionary of organic compounds , p. 932 ( limited preview in Google book search).
2. ↑ There is not yet a harmonized classification for this substance . A labeling of 4-bromopyrocatechol in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), which was accessed on December 28, 2019, is reproduced from a self-classification by the distributor .
3. ↑ ^{a b} Safety Data Sheet 4-Bromocatechol. (PDF) Apollo Scientific Limited, April 4, 2017, accessed March 5, 2020 . 
4. ↑ KW Rosenmund, W. Kuhnhenn: About a method for the bromination of organic compounds , in: Reports of the German Chemical Society , 1923 , 56  (6), pp. 1262-1269; doi : 10.1002 / cber.19230560605 .
5. ^ Association of authors: Organikum , 19th edition, Johann Ambrosius Barth, Leipzig · Berlin · Heidelberg 1993, ISBN 3-335-00343-8 , p. 331.
6. ^ Association of authors: Organikum , 19th edition, Johann Ambrosius Barth, Leipzig · Berlin · Heidelberg 1993, ISBN 3-335-00343-8 , p. 653.