139520-06-2Relevant academic research and scientific papers
Furans and thiophenes from etacrynic acid
Gorlitzer,Bomeke
, p. 9 - 12 (2007/10/02)
The 1,4-dicarbonyl- and 1,4,7-tricarbonyl compounds 1 react with polyphosphoric acid (PPA) to yield the furans 3; with P4S10 the thiophenes 4 are obtained. The γ-keto carboxylic acid 2 cyclizes with PPA to form the α,β-unsaturated butyrolactone 6. 2 is reduced by NaBH4 chemo- and diastereoselectively to give the γ-hydroxy carboxylic acid 5. The lactone 7 is prepared by dehydration of 5 with PPA. The sulfones 8a,b are obtained from the thiophenes 4a,b by oxidation with magnesium monoperoxyphthalate (MMPP). Under the same conditions the furan 3b is cleaved to yield the enedione 9, which tautomerizes slowly forming 10.
