Water → Thiophene-2-sulfonyl bromide

Temperature

15 °C

In the reaction, excess hydrazine in the presence of a solvent, advantageously a lower alkanol, is reacted with the 2-thiophenesulfonyl chloride to form a 2-thiophenesulfonyl hydrazine. In the reaction, the 2-thiophenesulfonyl chloride is gradually added to the hydrazine solution which is maintained at a low temperature, advantageously between about 5° and up to about 15° C. The reaction mixture is then allowed to warm to room temperature, the solvent is removed in vacuo and a mixture of a heavy oil and a fluffy solid results. This mixture is treated with water and the solid is dissolved and the oil separated therefrom. This mixture of oil and water, which contains the hydrazine hydrochloride from the first reaction, is then placed in a flask containing a bromine solvent, advantageously chloroform, crushed ice is added thereto and to the resulting slurry bromine is added at such a rate that the reaction temperature remains below about 10° C. After the bromine has been added and the bromine color has dissipated, the layers are separated, the chloroform layer is dried over an appropriate desiccant, advantageously anhydrous magnesium sulfate, and the chloroform removed in vacuo to leave a yellow oil which crystallizes on addition of hexane to give the 2-thiophenesulfonyl bromide.

1. customIn the reaction
2. temperatureto warm to room temperature
3. customthe solvent is removed in vacuo
4. additiona mixture of a heavy oil
5. customa fluffy solid results
6. dissolutionthe solid is dissolved
7. customthe oil separated
8. additionThis mixture of oil and water, which
9. customfrom the first reaction
10. customis then placed in a flask
11. customcrushed ice
12. additionis added
13. customremains below about 10° C
14. customthe layers are separated
15. dry with materialthe chloroform layer is dried over an appropriate desiccant, advantageously anhydrous magnesium sulfate
16. customthe chloroform removed in vacuo
17. customto leave a yellow oil which
18. customcrystallizes on addition of hexane

ORD record

ord-e6a43b27644f43efa6c48fdfeb531030

Source dataset

uspto-grants-1981_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04264774