Chlorine → 2-Thiophenecarboxaldehyde, 4,5-dichloro-

To a mechanically stirred solution of 31.8 grams (0.217 mole) 5-chloro-2thiophenecarboxaldehyde in 150 ml of methylene chloride, 65 grams (0.487 mole) of anhydrous aluminum chloride was added in small portions. The mixture exothermed and turned purple. To this mixture 20.6 grams (0.29 mole) of chlorine in 250 ml of carbon tetrachloride was added dropwise. The reaction mass was refluxed for about 15 hours, and an additional 15 grams (0.21 mole) of chlorine in 200 ml of carbon tetrachloride was added. The mixture was refluxed for an additional 7 hours. The reaction was quenched by pouring over one liter of ice water. The aqueous layer was extracted with chloroform. The chloroform solution was washed with water and sodium bicarbonate. After drying with anhydrous sodium sulfate and concentration under vacuum, a yellow-brown oil was obtained. The crude 4,5-dichloro-2-thiophenecarboxaldehyde crystallized on standing and was recrystallized from hexane.

1. temperatureThe reaction mass was refluxed for about 15 hours
2. temperatureThe mixture was refluxed for an additional 7 hours
3. customThe reaction was quenched
4. additionby pouring over one liter of ice water
5. extractionThe aqueous layer was extracted with chloroform
6. washThe chloroform solution was washed with water and sodium bicarbonate
7. dry with materialAfter drying with anhydrous sodium sulfate and concentration under vacuum
8. customa yellow-brown oil was obtained
9. customThe crude 4,5-dichloro-2-thiophenecarboxaldehyde crystallized
10. customwas recrystallized from hexane

ORD record

ord-173897e50ca64886aa8fcc8ea84207e5

Source dataset

uspto-grants-1980_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04192884