Nitration trifluoromethanesulfonic acid

Attempts of further nitration of dinitro derivative 83 under usual conditions failed. Using 100% nitric acid in fluorosulfonic acid or trifluoromethanesulfonic acid, reagents useful for nitration of deactivated aromatic systems led to the formation of moisture-sensitive nitration products, which undergo further oxidation to give o-quinone-like species 84 and 85. Using the latter conditions, compound 86 can be isolated in 20% yield and converted into the tetraoxo derivative 85 by heating at 220°C (Scheme 4) <1996JOC1898>. 

Trifluoromethanesulfonic acid, Acyl chlorides, Aromatic hydrocarbons, 0375 Trimethylsulfonium chloride, 1303 Trimethylsulfoxonium bromide, 1299 Uronium nitrate, 0494... 

The nitration of thiazoles can also be conducted in organic solvents (e.g., dichlo-roethane) with a nitrating mixture consisting of trifluoromethanesulfonic acid, its anhydride, and potassium nitrate. Here the yields of the nitro derivatives are substantially higher than with the sulfuric-nitric acid mixture [361],... 

The electrophilic substitution is the most characteristic reaction for these classes of compounds. Compound (21) undergoes standard electrophilic aromatic substitution reactions. Thus it forms the 6-bromo compound (58) with A7-bromosuccinimide and 6,7-dibromo compound (72) with the excess of the same reagent. It also forms the 6-nitro compound (67) with copper(II) nitrate trihydrate and 6,7-dinitro compound (68) with excess of nitronium tetrafluoroborate. The bis(trifluoro-acetoxy)thallium derivative (73) was formed from trithiadiazepine (21) and thallium(III) trifluoro-acetate in refluxing acetonitrile. Without isolation, (73) was directly converted into the pale yellow 6-iodo compound (74) with aqueous potassium iodide, into the 6-cyano compound (75) with copper(I) cyanide, and into methyl trithiadiazepine-6-carboxylate (76) with carbon monoxide and methanol in the presence of palladium chloride, lithium chloride, and magnesium oxide. Compound (21) is acetylated in the presence of trifluoromethanesulfonic acid (Scheme 7) <85CC396,87JCS(P1)217, 91JCS(P1)2945>. 

Trifluoromethanesulfonic acid (triflic acid) is one of the strongest known Bronsted acids. Ho for CF3SOsH is -14.5, comparable to fluorosuifuric acid. Additionally, while fluorosuifuric acid, like sulfuric acid, is also a powerful sulfonating and oxidizing agent, trifluoromethanesulfonic add does not react with aromatics [6], It is therefore a most convenient strong acid for nitration with nitric acid, which is completely ionized by it. 

During an investigation on the effect of acids on the regioselectivity of nitration of toluene, Coon, Blucher and Hill found that two equivalents of trifluoromethanesulfonic acid react with 100% nitric acid to yield a while crystalline solid, which is a mixture of nitronium trifluoromethanesulfonate and hydronium trifluoromethanesulfonate [7]. 

The mixture of nitric acid and trifluoromethanesulfonic acid in CHjClj, CCI4, CF2CI2, CFQ3, and pentane solution is an excellent nitrating agent for benzene, toluene, m-xylene, chlorobenzene, nitrobenzene, and beozo-trifluoride (Table II). The reactions were carried out from —110 to 30 C. Mono- or dinitration of toluene can be controlled by specific reaction temperature. Mononitration of toluene is extremely rapid, the reaction being complete in one minute at -110X. The dinitration is complete in 30 min at 0 C. 

Amino[2.2]paracyclophane and diamino[2.2]paracyclophane can be accessed by the nitration with trifluoromethanesulfonic acid/nitric acid and reduction of the nitro group with strategy incorporating triiron dodecacarb-onyl. F33(CO)i2 is a powerful reductant even under mild reaction conditions. Crown ethers are used as a phase transfer catalyst. The reaction scheme is shown in Figure 2.2. 

Acylation of 4 with acid anhydrides in the presence of trifluoromethanesulfonic acid389 gives monoacyl derivatives 9. 6-Acetyltrithiadiazepine 9a undergoes bromination to give 6-acetyl-7-bromo-l,3/.4,5,2,4-trithiadiazepine (10) nitration gives a mixture of the nitro derivative 11 and the dcacctylated compound 5.387... 

The cyclohexadiene complex 29 has been further elaborated to afford either the cydo-hexenone 34 or the cyclohexene 36 in moderate yields (Scheme 1) [21]. The addition of HOTf to 29 generates the oxonium species 33, which can be hydrolyzed and treated with cerium(IV) ammonium nitrate (CAN) to release the cyclohexanone 34 in 43 % yield from 29. Alternatively, hydride reduction of 33 followed by treatment with acid eliminates methanol to generate the r 3-allyl complex 35. This species can be trapped by the conjugate base of dimethyl malonate to afford a cyclohexene complex. Oxidative decomplexation of this species using silver trifluoromethanesulfonate liberates the cyclohexene 36 in 57 % overall yield (based on 29). 

A,iV-DIMETHYLMETHANIDE (68-12-2) Forms explosive mixture with air (flash point 136°F/58 C). Violent reaction with nitrates, carbon tetrachloride, hexachlorocyclohexane, and other halogenated compounds, particularly in contact with iron or strong oxidizers, may cause fire and explosions. Vigorous reaction with alkylaluminums. Incompatible strong acids, allyl trifluoromethanesulfonates, ammonia, chlorinated hydrocarbons, cresols, chromic anhydride, isocyanates, nitrates, phenols, magnesium nitrate, methylene diisocyante, phosphorous trioxide, triethyl aluminum. Attacks some plastics and coatings. 

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