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An effective, novel and rapid one-pot three-component route to quinazolin-4(3H)-ones from commercially available starting materials is described. Isatoic anhydride reacts with acyl chlorides and different amines using a combination of trifluoromethanesulfonic anhydride (Tf2O) and 2-chloropyridine (2-ClPy) to produce the corresponding quinazolinone derivatives in good to excellent yields.

Low temperature activation of amides (I) with triflic anhydride and 2-chloropyridine allows the C-O bond formation with aromatic alcohols to N-arylimidates.

An efficient and direct one-pot glycosylation method using anomeric hydroxy sugars as glycosyl donors, employing 3-fluorophthalic anhydride and triflic anhydride as activating agents, has been developed. The present glycosylation utilizing 3-fluorophthalic anhydride resulted in few to no undesired self-condensed esters than the glycosylation using phthalic anhydride. Intermediates in the present glycosylation were identified by an NMR study.

A convenient method for stereoselective synthesis of 1,2-trans-ribofuranosides directly from 1-hydroxy sugars and alcohols or trimethylsilylated nucleophiles by the use of [1,2-benzenediolato(2−)-O,O′]oxotitanium and trifluoromethanesulfonic anhydride is described.

A method of hydrolyzing 2-aryl-4,4-dimethyl-2-oxazolines with trifluoromethanesulfonic anhydride is described which works well even for highly hindered systems where alternate methods fail.

1,2-trans-Ribofuranosides are stereoselectively synthesized in high yields directly from 1-hydroxy ribofuranose and trimethylsilylated nucleophiles by the use of diphenyltin sulfide and trifluoromethanesulfonic anhydride. Even further, in the coexistence of lithium perchlorate, 1,2-cis-ribofuranosides are prepared predominantly in high yields.

Three-component reactions with aldehydes, trimethylsilyl trifluoro- methanesulfonate or iodide. and triphenylphosphine (TPP) yield the title compounds. The X-ray structure of the cationic part of a representative product, the (4-methylphenyl)[(trimethylsiloxy) methyl]TPP + , shows an interesting lengthening of the P + -C(α) bond compared with reported values for methyl(TPP) + and benzyl(TPP) + cations (C(α) represents the P-bonded carbon atom of the various alkyl groups). The behavior of the title compounds towards charged nucleophilic reagents and a powerful electrophile (trifluoromethanesulfonic anhydride) is similar to that of analogous pyridinium salts

A reagent prepared in situ from iodosobenzene (PhIO) and trifluoromethanesulfonic anhydride (Tf2O) was successfully applied to the activation of thioglycosides. Glycosidation with benzyl-protected methyl thioglycosides as glycosyl donors proceeded smoothly under mild reaction conditions. The same reagent also promoted glycosidation with less reactive acylated methyl thioglycosides in the presence of silica gel to form 1, 2-trans glycosides.

β-D-Ribofuranosides are stereoselectively synthesized in high yields directly from 2,3,5-tri-O-benzyl-D-ribofuranose and trimethylsilylated nucleophiles by the use of [catecholato(2−)-O,O′ ]oxotitanium and trifluoromethanesulfonic anhydride, while α-D-ribofuranosides are prepared predominantly in high yields in the coexistence of lithium perchlorate.

The disulfide dication salt, 1,5-dithioniabicyclo[3.3.0]octane bis(trifluoromethanesulfonate) ( 3 ), was isolated from the reaction of 1,5-dithiacyclooctane 1-oxide with trifluoromethanesulfonic anhydride. Two-electron oxidation of 1,5-diselenacyclooctane with two equivalents of NOPF 6 or NOBF 4 gave the first diselenide dication salt, 1,5-diselenoniabicyclo-[3.3.0]octane bis(hexafluorophosphate) or bis(tetrafluoroborate ( 5 ). The disulfide and diselenide dication salts ( 3 and 5 ) act as an oxidant or as an electrophile depending on the added reagents.

Due to the interest in tetrazoles as medicinal agents, a new, mild one-step method for the conversion of amides to tetrazoles employing triphenylphosphine, diethyl azodicarboxylate, and trimethylsilyl azide was recently introduced. An alternate and equally simple method employing trifluoromethanesulfonic anhydride and sodium azide was devised. This method was used to synthesize a series of 1,5-substituted tetrazoles from readily available secondary amides. A 1H-substituted tetrazole was also synthesized by this method from an amide substituted with a cyanoethyl protecting group

An efficient preparation of β-amino-α,α-difluoroketones 4 was developed. Reactions of 1,1-difluorovinyl methyl ethers 1 with N-acyliminium intermediates, generated by treating biscarbamates 2 with trifluoromethanesulfonic anhydride (Tf2O) in the presence of molecular sieves 4A (MS 4A), provided 4 in good yields.

The reaction of N,N-dimethylacrylamide/trifluoromethanesulfonic anhydride complex with electron-rich aromatic compounds affords after hydrolysis the corresponding indanones and 1,3-diarylpropanones.

Aldehydes and ketones were converted into 2-methylsulfinyl-5,6-dihydro-4H-1,3,4-thiadiazines via the formation and base-induced ring-closure of N-alkylidene-N′-bis(alkylthio)methylenehydrazines followed by mCPBA oxidation. The subsequent Pummerer-type ring fission of the rings was performed by treating with trifluoroacetic anhydride or trifluoromethanesulfonic anhydride at −78 °C to give α,β-unsaturated esters and ketones in modest yields. Thus, this reaction sequence was regarded as being a new method for the two-carbon homologation of aldehydes and ketones.

The reaction of N , N -dimethylacrylamide/trifluoromethanesulfonic anhydride complex with alkoxybenzenes followed by hydrolysis leads to the corresponding indan-1-ones and 1,3-diarylpropan-1-ones. Substituted naphthalenes yield dihydrophenalen-1-ones. Fused ring aromatics afford aromatic amines.

The reaction of aromatic amines with complexes of N,N-dimethylacrylamide and N,N-dimethylmethacrylamide with trifluoromethanesulfonic anhydride leads to the formation of tetrahydro-4-quinolones and 3-methyltetrahydro-4-quinolones respectively.

Diisopropylcyanamide reacts exothermically with trifluoroacetic anhydride to give 2, an equilibrium mixture, in C6D6 solution, of 1:1 adducts, N,N-diisopropyl-N‘,O-bis(trifluoroacetyl)isourea, 2a (10%), and N,N-diisopropyl-N‘,N‘-bis(trifluoroacetyl)urea, 2c (90%), at 27 °C. Compound 2c is a colorless solid, mp 49−51 °C. Thermolysis of 2, at 117 °C, shows first-order kinetics with the intital products being trifluoroacetonitrile, 4, and diisopropylcarbamic trifluoroacetic mixed anhydride, 3. Trifluoroacetonitrile trimerizes to 2,4,6-tris(trifluoromethyl)-1,3,5-triazine, and 3 is thermally labile giving diisopropyltrifluoroacetamide and CO2. In the thermolysis reaction 4 reacts with 2a to give a small amount of 4-(diisopropylamino)-4-(trifluoroacetoxy)-2,6-bis(trifluoromethyl)-4H-1,3,5-oxadiazine, 7. A related compound, 4,4-bis(diisopropylamino)-2,6-bis(trifluoromethyl)-4H-1,3,5-oxadiazine, 8, is formed from 7 and 2c going through a concentration maximum at 4000 s in the kinetic run. Compound 8 thermolytica...

The reaction of aliphatic esters with aliphatic or aromatic nitriles in the presence of trifluoromethanesulfonic anhydride affords substituted 4-alkoxypyrimidines in good yields. A mechanism of the investigated reaction is proposed.

Reactions of magnesium alkoxides with trifluoromethanesulfonic anhydride or triflates gave corresponding symmetrical or unsymmetrical ethers in moderate to good yields under mild reaction condition...

The synthesis of amidines was achieved by the addition of amines to amides that were previously activated with trifluoromethanesulfonic anhydride (triflic anhydride) and pyridine. Various disubstituted and trisubstituted amidines were prepared in yields up to 84%.

Polysubstituted amidines, benzimidazoles and pyrimidines were synthesized via the electrophilic activation of amides with trifluoromethanesulfonic anhydride and 2-chloropyridine. The one-pot protocol is concise and efficient and the substrates are readily available.

The reaction of primary alcohols with trifluoromethanesulfonic anhydride in the presence of poly(4-vinylpyridine) [or poly(2,6-di-tert-butyl-4-vinylpyridine)] allows the isolation of the corresponding alkyl triflates in good yields. The quaternisation of 3,8-bis(ethoxycarbonylamino)-6-phenylphenanthridine (1) using these alkyl triflates was found to proceed smoothly at room temperature in nitrobenzene or chlorobenzene. Deprotection of these quaternary compounds using concentrated hydrobromic acid was found to be a more useful procedure than the previously reported use of concentrated sulfuric acid. The synthesis of the novel ethidium derivative 3,8-diamino-5-(5-aminopentyl)-6-phenylphenanthridinium bromide (12) is reported.

Syntheses of pyrrolo[2,1-f][1,2,4]triazine C-nucleosides are reported. Treatment of pyranulose glycoside with aminoguanidine in acetic acid gave the corresponding semicarbazone in 96% yield. The ring transformation of the semicarbazone in dioxane afforded a 51% yield of 2-amino-7-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)pyrrolo[2,1-f]-[1,2,4]triazine. Vilsmeier formylation of the pyrrolotriazine gave the major product, 5-formylpyrrolo[2,1-f][1,2,4]triazine, in 69% yield. The aldehyde was treated with hydroxylamine hydrochloride in methanol to give aldoximes. Dehydration of aldoxime with trifluoromethanesulfonic anhydride and triethylamine in dichloromethane afforded 5-cyanopyrrolo[2,1-f][1,2,4]triazine in 44% yield. Conversion of the nitrile to the deprotected amide, 2-amino-7-(beta-D-ribofuranosyl)pyrrolo[2,1-f][1,2,4]triazine-5-carboxamide, was accomplished in 96% yield on treatment with 30% H2O2 in ethanol for 1 day at room temperature. Debenzoylation with sodium hydroxide solution produced deprotected C-nucleosides.

Low temperature mannosylation of glycosyl acceptors under the agency of S-(4-methoxyphenyl) benzenethiosulfinate (MPBT) and trifluoromethanesulfonic anhydride (Tf2O) with p-methoxyphenyl 2-azido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-1-thio-α- d -mannopyranoside, readily available from d -mannosamine hydrochloride, affords 2-azido-2-deoxy- d -mannosides with high β-selectivity in good yields.

Benzyl nitriles bearing electron donating groups react with ketones in the presence of trifluoromethanesulfonic anhydride to form naphthalene amines and related compounds. In contrast, the same benzyl nitriles substituted with electron withdrawing groups form the corresponding 2,4-dibenzyl substituted pyrimidines. A mechanism is proposed that explains the divergence in reaction paths leading to these products.

Novel rhodamine dyes were prepared from xanthone precursors in a 'one-pot' procedure via reaction of the xanthone with trifluoromethanesulfonic anhydride followed by Pd-mediated Suzuki coupling between the xanthone triflate and an arylboroxin. Rhodamines with 9-(3- or 4-carboxyphenyl) and 9-(3-nitrophenyl) substituents were prepared by this procedure. The procedure also works well with thio- and selenoxanthones, but not with telluroxanthones.

Alpha-mannopyranosyl phosphosugars are obtained in 61-90% yields from 4,6-O-benzylidene-protected mannosyl thioglycosides bearing ester functionality in the 3-O-position by coupling reactions with ammonium salts of phosphosugars on activation with 1-benzenesulfinyl piperidine, 2,4,6-tri-tert-butylpyrimidine, and trifluoromethanesulfonic anhydride. Due to the presence of the disarming ester group, only the formation of the alpha-isomer was observed.

We studied the thermal behavior of some intermediates formed by reaction of nitriles with perfluoroalkyl sulfoxides upon trifluoromethanesulfonic anhydride activation. Bistriflate ketal 3, precursor of sulfilimine 1, may undergo a rearrangement to sulfanyl nitrile 5 after triflic acid elimination under thermal conditions. With p-tolyl trifluoromethyl sulfoxide, remote triflic acid elimination from intermediate 4 leads to benzamide 8 formation. These reactions involve, respectively, selective functionalization of the aromatic ortho C–H bond or the benzylic C–H bond para to the sulfoxide group. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

The species obtained by activation of perfluoroalkylated sulfoxides with trifluoromethanesulfonic anhydride behaves as highly electrophilic entities. Their reaction with nitriles allows a Ritter-like process leading to the new fluorinated acylsulfilimines 1–21 after hydrolysis. This flexible methodology allows some variation of both the sulfoxide and nitrile components. Derived acylsulfoximines 22–25 or free sulfoximines 26–28 could be selectively obtained, as needed, by further controlled oxidation with the cheap and nontoxic potassium permanganate. This oxidation may be performed either after isolation of the intermediate sulfilimine, or more conveniently in a one-pot process directly from fluorinated sulfoxides. This versatile, solvent and metal free, reaction is thus an opening way through the synthesis of new ligands or electrophilic trifluoromethylating reagents.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

2H-Cyclohepta[b]furan-2-ones (2a,b) reacted with dimethyl sulfide dittiflate to give dimethyl(2-oxo-2H-cyclohepta[b]furan-3-yl)sulfonium trifluoromethanesulfonates (3a,b), which were treated with Et 3 N to give 3-methylthio-2H-cyclohepta[b]furan-2-ones (4a,b). Sulfides 4a and 4b were oxidized with m-CPBA to give corresponding sulfoxides (5a,b) and sulfones (6a,b). The sulfoxides (5a,b) thermally underwent coupling reaction to give 3,3'-bi-2H-cyclohepta[b]furan-2-ones (7a,b). The sulfoxides (5a,b) reacted with trifluoromethanesulfonic anhydride (Tf 2 O) to afford sulfonium ions 8a and 8b at lower temperature, which reacted with 2a or 2b to give sulfonium ions (9a-c). Treatment of compounds 9a-c with Et 2 NH or Et 3 N gave corresponding sulfide products (10a-c).

The direct conversion of various amides to isoquinoline and β-carboline derivatives via mild electrophilic amide activation, with trifluoromethanesulfonic anhydride in the presence of 2-chloropyridine, is described. Low-temperature amide activation followed by cyclodehydration upon warming provides the desired products with short overall reaction times. The successful use of nonactivated and halogenated phenethylene derived amides, N-vinyl amides, and optically active substrates is noteworthy.

Treatment of N-arylisonicotinamides with trifluoromethanesulfonic anhydride triggers intramolecular nucleophilic attack of the aryl ring on the 4-position of the pyridinium intermediate. The products are spirocyclic dihydropyridines which can be converted to valuable spirocyclic piperidines related to biologically active molecules such as MK-677.

Extended Pummerer reaction of arylketene dithioacetal monoxides with aromatic compounds by means of trifluoromethanesulfonic anhydride proceeded in moderate to good yields. In the case of intramole...

An efficient direct one-pot glycosylation method with anomeric hydroxy sugars as glycosyl donors employing phthalic anhydride and triflic anhydride as activating agents has been developed. Thus, highly stereoselective beta-mannopyranosylations were achieved by the reaction of 2,3-di-O-benzyl-4,6-O-benzylidene-D-mannopyranose (2) with phthalic anhydride in the presence of DBU at room temperature followed by sequential addition of DTBMP and Tf2O and glycosyl acceptors to the reaction mixture at -78 degrees C in one-pot. Stereoselective alpha-glucopyranosylations with 2,3-di-O-benzyl-4,6-O-benzylidene-D-glucopyranose (25) and other glycosylations with glucopyranoses and mannopyranoses having tetra-O-benzyl- and tetra-O-benzoyl protecting groups were also possible by utilizing the present one-pot glycosylation protocol. The possible mechanism for the beta-mannosylation with 2 was proposed based on the NMR study, in which alpha-mannosyl phthalate 55alpha and alpha-mannosyl triflate 59 were detected as intermediates. The versatility and efficiency of the present glycosylation methodology, especially those of the beta-mannopyranosylation protocol, were readily demonstrated by the efficient synthesis of protected beta-(1-->4)-D-mannotriose 62 and beta-(1-->4)-D-mannotetraose 67 with perfect beta-stereoselectivity.

A variety of N-vinyl and N-aryl amides were converted in one step into the corresponding pyrimidine and quinazoline derivatives, respectively. Amide activation with trifluoromethanesulfonic anhydride in the presence of 2-chloropyridine followed by nitrile addition to the activated amide derivative and annulation provides the desired azaheterocycles.

Treatment of arylketene bis(methylthio)acetal monoxide with trifluoromethanesulfonic anhydride leads to ring-closure to afford 2-methylthiobenzo[b]thiophene in high yield. The reaction is useful for synthesizing multisubstituted benzo[b]thiophenes.

This communication describes the chemoselective metal-free reduction of tertiary amides to the corresponding amines. Hantzsch ester is used as a mild reducing agent for the reduction of trifluoromethanesulfonic anhydride activated amides providing the tertiary amines with high functional group tolerance.

A novel reagent combination, Tf 2 O/Na 2 CO 3 ·1.5H 2 O 2 , has been developed for the oxidation of highly electron deficient pyridines to their corresponding N -oxides. The N-oxidation reaction, utilizing the in situ generated peracid, proceeds under mild conditions that allow for a number of functional groups and substitution patterns on the pyridine ring.

A method has been developed for the synthesis of 4-amino-substituted 7-benzyl-2-morpholin-4-yl-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidines by condensation of ethyl 1-benzyl-3-oxopiperidine-4-carboxylate with morpholine-4-carboxamidine and subsequent reaction of the 7-benzyl-2-morpholin-4-yl-5,6,7,8-tetrahydro-3H-pyrido[3,4-d]pyrimidin-4-one with trifluoromethanesulfonic anhydride and secondary amines.

A series of 4,6-O-benzylidene-protected 2-O-benzyl-3-deoxy-3-fluoro- and 3-O-benzyl-2-deoxy-2-fluorogluco- and mannopyranosyl thioglycosides were synthesized and their coupling reactions with a series of alcohols, on preactivation with 1-benzenesulfinylpiperidine and trifluoromethanesulfonic anhydride, investigated. In all cases, the selectivities were lower than those observed with the corresponding simple 4,6-O-benzylidene 2,3-di-O-benzylgluco- and mannopyranosyl thioglycosides. This leads to the conclusion that the high beta-selectivity observed with 4,6-O-benzylidene 2,3-di-O-benzylmannopyranosyl donors under the same conditions is in large part derived from the compression of the O2-C2-C3-O3 torsion angle on going from the intermediate covalent glycosyl triflate to the oxacarbenium ion, as compared to the relaxation of this torsion angle in the gluco series.