Trifluoromethyl derivatives

The recent discovery of a convenient synthesis of sulfur tetrafluoride from sulfur dichloride and sodium fluoride in acetonitrile invited the application of this reagent in fluorination reactions. Hasek, Smith and Engelhardt showed that carboxylic acids and their derivatives can be converted into trifluoromethyl derivatives and that aldehydes and ketones are converted into 5 em-difluoro compounds. They also observed that the reaction was acid... 

Trifluoromethyl Derivatives of the Transition Metal Flements 1984 Synthesis and Properties of Aryl... 

The reaction of cyclohexane-cw-1,2-dicarboxylic acid with sulfur tetrafluoride affords the correspoding cyclic ether in a 70% yield with very limited formation of the bis(trifluoromethyl) derivative [2IJ] (equation 107)... 

Previous extended Hiickel calculations on the bis(trifluoromethyl) derivative 6 show the favored isomer to be 6b, while the CNDO/2 method favors 6a [75JCS(P2)559]. More recent ab initio calculations for different R substituents show that electron-releasing substituents favor the ring-opened dithione (6b), whereas electron-withdrawing substituents favor the cyclic structure (6a) (80JA6687). These conclusions are supported by electron diffraction (ED) (76JA899) and photoelectron (PE) spectral data... 

The trifluoromethyl derivative 146 has been obtained as a minor product from the reaction of (l-methyhndol-3-yl)methanol with trifluoroacetic acid anhydride (TFAA), the major product (22% yield) being 6-trifluoromethylindolo[3,2-()]-carbazole [98LTC(B)841]. Several substituted indolo[2,3-()]carbazoles have also been encountered during studies on the reaction of 4,6-dimethoxyindole with... 

Similar results were obtained in methanol (ref. 30), where for the bis-(trifluoromethyl) derivative the ratio between the return of the trans bromonium ion to the trans olefin and its collapse to products 2 and 6 is 4.5 and is again very strongly reduced by the presence of LiC104 (Table 9). In this solvent, however, return was not observed for unsubstituted stilbene, either. It can be observed that both cis - and trans -stilbene gave methoxybromo adducts in an anti stereospecific way, suggesting a nucleophilic assistance by the solvent. 

Figure 56.2 Synthetic sequence followed by students for the synthesis of catalysts for evaluation. Bis(trifluoromethyl) derivative (6h) was prepared by the procedure ofLeazer etal. ...

For commonly encountered heterocycles, the chemical shifts of trifluo-romethyl substituents will depend somewhat upon where in the heterocycle they are located. Examples of trifluoromethyl derivatives for a number of common heterocycles, including pyridines, quinolines, pyrroles, indoles, thiophenes, benzothiophenes, furans, benzofurans, imidazoles, and uracils are given below. 

Attempted syntheses of trifluoromethyl derivatives of germanium, tin, and lead by thermal decarboxylation either resulted in decomposition of the trifluoroacetate without forming carbon dioxide (22,39,40) or gave carbon dioxide but no trifluoromethyl organometallic (22). In the latter case, the metal fluoride was detected. This suggests that the trifluoromethyl compound is thermally unstable and decomposes by fluoride abstraction. 

The acyclic ADC compounds I and 2 are usually isolable, and reasonably stable, although the trifluoromethyl derivative (1, R = CF3) is reported to be unstable.15 In general, the diesters 2 have found greatest use in synthesis, with DEAZD (2, R = Et) being the most commonly used it is available commercially. 

Adrenergic neurone blocking activity is increased when substituents are introduced into the ortho- and para-positions of benzylguanidine (Table 3.18) active compounds include the bromo (a particularly close analogue of bretylium), chloro and trifluoromethyl derivatives (LIV, R = 2-Br, 2-Cl, 2- and 4-CFa) [140, 141, 239, 242]. The 4-trifluoromethyl derivative, which has a relaxing effect on the nictitating membrane of cats comparable in intensity and duration to bethanidine, also decreased blood pressure in hypertensive dogs [141]. Certain... 

Azizian J, Mirza B, Mojtahedi MM, Abaee MS, Sargordan M (2008) Biginelli reaction for synthesis of novel trifluoromethyl derivatives of bis(tefrahydropyrimidinone)benzenes. J Fluor Chem 129 1083-1089... 

Trifluoromethyl derivatives of aziridine are intensively studied as biologically active substances. (Trifluoromethyl)aziridines 4 were prepared from (trifluoromethyl)ketoximes 3 and Grignard reagents (equation 2). However, this reaction is not general. For example, reaction does not occur with phenyl and allyl Grignard reagents, but when it works the Z stereoisomer is formed . 

OrganometaUoidal Fluorine Compounds. Part III. Trifluoromethyl Derivatives of Sulphur. J. Chem. Soc. 1952, 2198. 

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