ChemInform Abstract: MONO‐ UND BIS‐(TRIFLUORMETHYL)‐FURANE

Abstract

Ein 45stündiges Erhitzen der Furandicarbonsäure (I) mit SF4 im Autoklaven auf 185°C liefert ein Gemisch der Trifluormethylverbindungen (II) und (III); analog erhält man aus der Dicarbonsäure (V) ein Gemisch der Fluorierungsprodukte (VI)‐(VIII), aus der Dicarbonsäure (IX) schon bei 1 15°C (in Gegenwart von HF) ein Gemisch der Fluorierungsprodukte (X) und (XI).

Synthesis of fluorofurans and perfluoroalkylfurans

“…The reaction of furan tetracarboxylic acid with sulfur tetrafluoride in the anhydrous HF medium leads to the formation of 4,6- [84]. Some reactions of this type are already mentioned above (Scheme 37 [85]).…”

“…5-(Trifluoromethyl)furan-2-carboxylic acid is also formed in 4% yield as a minor product of this transformation [37,38].…”

“…In a-fluoroalkyl and a-perfluoroalkylfurans syntheses based on the fluorination of existent a-substituents in the furan ring, furan-2-carboxylic acids, aldehydes, ketones, and alcohols are common substrates (Table 1) [37][38][39][40][41].…”

“…The reaction of 2-methyl-, 2-trifluoromethyl furan-3,4-dicarbocylic acids and furan-2,3,4-tricarboxylic acid proceeds similarly at 150-220 8C (Scheme 35)[62,84]. Depending on the reaction temperature and amounts of sulfur tetrafluoride the products of complete and partial fluorination can be obtained (Scheme 36)[37]. The carboxylic groups at the position 3 are fluorinated easier than those in the position 2.…”

“…The reaction of furan-3,4-dicarbocylic acid with sulfur tetrafluoride in the HF medium at 100-120 8C gives 3,4-bis(trifluoromethyl)furan. The reaction of 2-methyl-, 2-trifluoromethyl furan-3,4-dicarbocylic acids and furan-2,3,4-tricarboxylic acid proceeds similarly at 150-220 8C (Scheme 35)[62,84]. Depending on the reaction temperature and amounts of sulfur tetrafluoride the products of complete and partial fluorination can be obtained (Scheme 36)[37].…”