Cyanuric fluoride, with

An almost quantitative yield of (trifluoromethyl)iminosulfur diiluoride (1), a gas stable up to 600°C, can be obtained by reacting 2,4,6-trifluoro-l,3,5-triazine (cyanuric fluoride) with sulfur tetrafluoride in the presence of cesium fluoride at 1553C.203... 

Gobrinoff, M. J. 1967. Exposusre of tyrosine residues in proteins. Reaction of cyanuric fluoride with ribonuclease, a-lactalbumin, and /3-lactoglobulin. Biochemistry 66, 1606-1614. 

Perfluoroalkylation of cyanuric fluoride with perfluorocarbanions goierated in situ from perfiuoro-oleflns and alkali-metal fluorides or triethylammonium fluoride in acetonitrile or dimethylformamide has been reported in the patent literature similarly, details of the preparation of perfluoroisopropoxy-substituted sym-triazines via treatment of cyanuric chloride with hexa-fluoroacetone and potassium fluoride in diglyme have been disclosed. ... 

Cyanuric fluoride is readily hydrolyzed to 2,4,6-thhydroxy-l,3,5-triaziae [108-80-5] (cyanuric acid). Cyanuric fluoride reacts faster with nucleophilic agents such as ammonia and amines than cyanuric chloride. 

Fiber-reactive dyes containing the fluorotriaziayl group are based on the condensation of chromophores containing amino groups with 6 - sub s titute d- 2,4- diflu o r o triaziae s. The latter can be prepared from cyanuric fluoride or from the reaction of alkah metal fluorides with... 

The acid fluoride (3 mmol), obtained from the carboxylic acid and cyanuric fluoride, and TBA-F (5 mg, 0.02 mmol) are added to the silylamine (3 mmol) in MeCN (5 ml) under N2 and the solution is stirred for 6 h at room temperature. The solvent is removed under reduced pressure and the residue is taken up in CH2Cl2. The organic solution is washed with aqueous NaHCO, (5%, 2 x 10 ml), aqueous HCI (4M, 2 x 10 ml) and H20 (20 ml), dried (Na2S04), and evaporated to yield the amide (>75%). 

Trichloro-l,3.5-triazine (cyanuric chloride, 5) can be converted using a sixfold excess of sulfur tetrafluoride at 250 C into 2,4,6-trifluoro-l,3,5-triazine (cyanuric fluoride, 6) with lower proportions of sulfur tetrafluoride, cyanuric chlorofluorides are formed.191... 

Deoxygenation of sulfoxides.1 This reaction can be carried out with cyanuric fluoride in dioxanc (3-9 hours, 65 80% yield). Cyanuric chloride (3, 72 4, 522 5, 687 6, 149) can be used in the case of aryl sulfoxides, but alkyl sulfoxides undergo Chlorination with this reagent. 

To a soln of Fmoc-TOAC-OH (0.437 g, 1.0 mmol) in CH2C12 at —10 °C were added cyanuric fluoride (0.085 mL, lmmol) and pyridine (0.081 mL, lmmol) under nitrogen. After stirring for lh at 0 °C the mixture was directly applied to a silica gel column and eluted with EtOAc/light petroleum ether (1 5). The product eluted first was identified as the oxazol-5(4T/)-one l 51 (0.110 g, 0.026 mmol yield 26%). The fluoride, which was eluted from the column immediately after the oxazolone, was obtained as a thick, orange oil yield 0.308 g (70%) IR (film) 1839,1715 cmA... 

In general, the chemistry of fluoro-l,3,5-triazines resembles that of the chloro derivatives, and therefore will not be discussed in detail. There is evidence that cyanuric fluoride is less reactive than cyanuric chloride in reaction with aniline (76CCC3378). Chambers et al. have reported the isolation of a stable anion cr- complex from the reaction of cyanuric fluoride and cesium fluoride (equation 32) (77JCS(Pl)l605). Such species are believed to be intermediates in the formation of (68) from cyanuric fluoride and perfluoropropene (equation 33). Olah et al. have shown that cyanuric fluoride deoxygenates sulfoxides efficiently (equation 34) (80S221). 

Cyanuric fluoride has been used to modify tyrosine residues, substituting the phenolic hydroxyl group. A maximum of 3 residues in RNase was found to react at pH 10.9 and 25° (148a). However, some mystery surrounds this number, as with other estimates of accessibility, since alkaline-denatured material where all tyrosine residues are available still showed the reaction of only 3 residues with cyanuric fluoride. However, similar observations have been made on iodination in 8 Af urea (11 )- At pH 9.3, Takenaka et al. (149) found that only 2 residues reacted and that 115 was not one of them. Two more reacted after alkali denaturation. Two were resistant under all conditions tested. No enzymic activity data were reported. 

The key step of the approach to 45 is the ring opening of /V-Boc p-lactam 43 with ammonia, Scheme 17. The synthesis starts from the 4-carboxy azetidin-2-one 41, which is a p-hydroxy aspartic acid form possessing the p-carboxyl group and the a-amino moiety simultaneously protected. The dipeptide unit 42 is obtained in 95% overall yield after activation of the a-carboxy group with cyanuric fluoride and... 

Other electrophiles that react with in situ-generated perfluorocarbanions in elude epoxides [226] equation 47), carbon dioxide [227] (equation 47) acyl halides [228, 229, 230, 20, 232, 233] (equation 48), fluoroformates [23d] car bonyl fluonde [23S, 236, 237] hexafluorothioacetone (generated from its dimei) [238] (equation 48), an a-fluoroalkylamine f2J9] (equation 48), cyanuric fluoride [240], and reactive alkyl halides [247, 242 243, 244, 245] (equation 49) Interestingly, an in situ-generated carbanion will also react with dibromodifluoromethane ia a mechanism involving difluorocarbene [246] (equation 50)... 

Alternatively, acid fluorides are used to activate the acid. Acyl fluorides are less sensitive to moisture and are more reactive toward primary and secondary amines than the corresponding acyl chloride. Furthermore, they are compatible with basic- (Fmoc and Cbz) or even acid- (Boc) labile amine protecting groups and less prone to promote racemization than their chlorinated homologs (26). Thus, the acid fluoride method is often used in peptide synthesis (27). Cyanuric fluoride 9 (28), TFFH (29), DAST (30), and deoxofluor (31) are used commonly as fluori-nating reagents (see Fig. 4). 

Olah GA, Nojima M, Kerekes I. Synthetic methods and reactions IV. 1 Huorination of carboxylic acids with cyanuric fluoride. Synthesis 1973 8 487. 

The acid fluorides are generally available via reaction of the acid with cyanuric fluoride in the presence of pyridine according to the general technique of Olah.t An alternative method for the synthesis of Fmoc amino acid fluorides involves the use of DAST (N,N-diethylaminosulfur trifluoride), which is advantageous relative to cyanuric fluoride owing to the formation of only water-soluble compounds as byproducts, thus, facilitating the isolation of the acid fluorides.Examples can be found in Table 3. 

Fmoc-Val-F with Cyanuric Fluoride Typical Proceduret d... 

Fmoc-Val-OH (0.339 g, 1 mmol) in CHjCh (5 mL) was refluxed under Nj with cyanuric fluoride (700 pL, 8 mmol) and pyridine (81 pL, 1 mmol) for 2 h. The mixture, from which a white water-soluble precipitate had settled, was extracted with ice water (2xl5mL). Removal of the solvent from the dry (MgS04) organic layer gave a white solid which was recrystallized (CH2CI2/hexane) to give the pure add fluoride yield 239mg (70%) mp 113-114 C. 

Fmoc-aminoacyl fluorides were prepared using either diethylaminosulfur trifluoride - DAST (8) or cyanuric fluoride (3) and kept under argon for long term storage. Although different Fmoc-aminoacyl fluorides were prepared with each reagent, one or the other method could be used for all (3,6). 

Fmoc-amino acids in methylene chloride were refluxed under N2 with cyanuric fluoride and pyridine (1 2 1 equiv.) for 3 h. The mixture was then washed with two portions of ice water, filtered to remove precipitated cyanuric acid and dried over anhydrous magnesium sulphate and filtered through a sintered funnel. Rotary evaporation produced a precipitate which was dissolved in a small amount of dry methylene chloride and crystallized by the addition of hexane. After stirring overnight, the resultant crystals were collected by filtration and dried under high vacuum (3) (Figure 1b). 

Preformed aminoacyi fluorides were prepared by two methods. Preparation of aminoacyl fluorides using DAST was accomplished using the method of Kaduk et. al f6) as shown in Figure la. Preparation with cyanuric fluoride using the method of Carpino et. al. (3) is shown in Figure 1b. 

A significant number of works are concerned with the development of new membranes for the separation of mixtures of aromatic/alicyclic hydrocarbons [10,11,77-109]. For example, the following works can be mentioned. A mixture of cellulose ester and polyphosphonate ester (50 wt%) was used for benzene/cyclohexane separation [113]. High values of the separation factor and flux were achieved (up to 2 kg/m h). In order to achieve better fluxes and separation factors the attention was shifted to the modification of polymers by grafting technique. Grafted membranes were made of polyvinylidene fluoride with 4-vinyl pyridine or acrylic acid by irradiation [83]. 2-Hydroxy-3-(diethyl-amino) propyl methacrylate-styrene copolymer membranes with cyanuric chloride were prepared, which exhibited a superior separation factor /3p= 190 for a feed aromatic component concentration of 20 wt%. Graft copolymer membranes based on 2-hydroxyethyl methylacrylate-methylacrylate with thickness 10 pm were prepared [85]. The membranes yielded a flux of 0.7 kg/m h (for feed with 50 wt% of benzene) and excellent selectivity. Benzene concentration in permeate was about 100 wt%. A membrane based on polyvinyl alcohol and polyallyl amine was prepared [87]. For a feed containing 10 wt% of benzene the blend membrane yielded a flux of 1-3 kg/m h and a separation factor of 62. 

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