Difluoromethyl trifluoroacetate

C3HO2F5, Difluoromethyl trifluoroacetate CHF20C(0)CF3, Cl, 876 C4H5O2F3, Ethyl trifluoroacetate, CH3CH20C(0)CP3 OH, 884 Cl, 884 ... 

Difluoroacetic acid and its derivatives (esters, aldehyde) are excellent reagents for introducing a difluoromethyl group. However, because they are expensive, they are used relatively infrequently. Their reactivity is close to that of trifluoroacetic derivatives. ... 

The one-pot reaction of the a-(difluoromethyl)-p-sulfinylenamine 70 with trifluoroacetic anhydride in CHCI3, followed by treatment with silica gel affords 4-(difluoromethyl)-5-p-tolylthio-2(3//)-oxazolone 74 (Fig. 5.18). This reaction proceeds via a Pummerer-type rearrangement, followed by [l,3]-proton shift and the simultaneous elimination of trifluoroacetic acid and benzyl alcohol. ... 

A series of 2-trifluoromethyl and 2-difluoromethyl substituted benzothiazoles 30 has been synthesized by a one-pot reaction of trifluoroacetic acid and difluoroacetic acid, respectively, with 2-aminobenzenethiol <07TL3251 >. The reaction pathway presumably involves the imidolyl chloride intermediate 29, which undergoes intramolecular nucleophilic substitution by neighbouring thiol under basic conditions to give benzothiazole 30. 

Trifluoroacetic acid at 300-390 °C produces mainly carbon dioxide, difluoro-methyl trifluoroacetate, carbon monoxide and trifluoroacetyl fluoride. Blake and Pritchard propose that the decomposition proceeds through the elimination of hydrogen fluoride, followed by the formation of difluorocarbene which largely adds to trifluoroacetic acid to form the difluoromethyl ester. The kinetic order is about 0.5 and the overall activation energy for the formation of carbon dioxide and the difluoromethyl ester is about 45 kcal.mole" ... 

Trifluoromethyl-l-oxa-2,4-diazole of 92 (Rf = CF3) is prepared by base-catalyzed condensation of 93 with trifluoroacetic anhydride in excellent yield (Scheme 12.13). The same method is applicable for the preparation of monofluor-omethyl, difluoromethyl, and 1,1-difluoroethyl compounds although their yields are low. The reaction of aminooxime 93 with 2-(trifluoroethylidene)-l,3-dithiane 95 under acid-catalyzed conditions, followed by ring-opening of the 1,3-dithiane ring and recyclization of oxadiazole ring provides 5-(2,2,2-trifluoroethyl)-l-oxa-2,4-diazole 96 in 38% yield (Scheme 12.13). °... 

This group was also able to prepare 3-difluoromethyl-3-cephem (225) by treatment of the aldehyde (224) with 7 equiv of piperidino sulfur trifluoride. The ester protective group in 225 was removed with trifluoroacetic acid, and subsequently the side-chain amide was cleaved with PCI5 in pyridine, giving the nucleus (227). Acylation of 227 afforded the... 

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