Baumann-Fromm thiophene synthesis

What is Baumann-Fromm thiophene synthesis?

Baumann and Fromm reported the synthesis of 2,4-diarylthiophenes in 1891 through the reaction of substituted styrenes with sulfur S8. The major product of this reaction is 2,4-diarylthiophene, although minor amounts of 2,5-diarylthiophenes are also formed.

Baumann-Fromm thiophene synthesis
Baumann-Fromm thiophene synthesis

Thiophenes can also be obtained from butadiynes by reacting with hydrogen sulfide, H2S. Benzothiophene is obtained by heating styrene with hydrogen sulfide, H2S, in the presence of a ferrous sulfide-alumina catalyst at 600 °C. Other methods for synthesizing thiophenes include the reaction between ethylbenzene and sulfur S8, acetophenone and hydrogen sulfide, H2S, or 1,4-diketones and phosphorus trisulfide, P2S3 (or phosphorus pentasulfide, P2S5).

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