Methanesulfonic phosphorus pentoxide

PPMA. See Phosphorus pentoxide-methanesulfonic acid (PPMA)... 

A powerful and efficient method for the preparation of poly(ketone)s is the direct polycondensation of dicarboxylic acids with aromatic compounds or of aromatic carboxylic acids using phosphorus pentoxide/methanesulfonic acid (PPMA)16 or polyphosphoric acid (PPA)17 as the condensing agent and solvent. By applying both of these reagents to the synthesis of hexafluoroisopropylidene-unit-containing aromatic poly(ketone)s, various types of poly(ketone)s such as poly(ether ketone) (11), poly(ketone) (12), poly(sulfide ketone) (13), and poly-... 

Only resinous products and methyl 6-acetamidopyridine-3-carboxylate were obtained when methyl 6-aminopyridine-3-carboxylate was reacted with ethyl 2-acetoxyacetoacetate by heating in phosphorus pentoxide, methanesulfonic acid, or polyphosphoric acid in the absence or presence of a solvent such as toluene, xylene, or methylene chloride. However the desired methyl 3-acetoxy-2-methyl-4-oxo-4//-pyrido[ 1,2-a]pyrimidine-7-carboxylate 93 was obtained when the above components were reacted in N, A-dimethylacetamide in the presence of polyphosphoric acid at 100°C for 48 hours (84FES837). 

Diaryl sulfones Phosphorus pentoxide-Methanesulfonic acid.j... 

Conventional condensation of 1,2-diaminobenzene 16 with 6-fluoro-3,4-dihydro-2H-chroman-2-carboxylic acid 17 under Phillips conditions or using Eaton s reagent (1 10 mixture of phosphorus pentoxide/methanesulfonic acid) yielded 2-(6-fluorochroman-2-yl)-lff-benzimidazole 18 (Scheme 4) [30]. However, irradiating the reaction mixture containing polyphosphoric acid as a catalyst with microwaves afforded the compoimd 18 in comparable yields in a matter of three minutes [30]. 

LACTONIZATION Boron trifluoride etherate. 2-Chloro-l-methyl-pyridinium iodide. 2,2 -Dipyridyl disulfide-Triphenylphosphine. Phosphorus pentoxide-Methanesulfonic acid. Triphenylphosphine-Diethyl azodicarboxylate. 

Multi-walled carbon nanotubes can be functionalized with PBI via a Friedel-Crafts acylation reaction in a phosphorus pentoxide/methanesulfonic acid medium [23]. The composites have been used as reinforced fillers in 100% acidified poly(hydroxyamino-ether) to prepare mixed composites. The acid-base interaction between the PBI chains attached on multi-walled carbon nanotubes plays a crucial role with regard to good dispersion and effective reinforcement. 

Ueda et al. established a modified method for the synthesis of PBOs (Figure 5.25) from 4,4 -oxydibenzoic acid and 3,3 -dihydroxybenzidine-dihydrochloride by using phosphorus pentoxide/ methanesulfonic acid (PPMA) as the condensing agent in place of PPA [54]. 

M. Ueda, H. Sugita, M. Sato, Synthesis of poly(benzoxazole)s by direct polycondensa-hon of dicarboxylic acids with 3,3 -dihydroxy-benzidine dihydrochloride using phosphorus pentoxide/methanesulfonic acid as condensing agent and solvent, J. Polym. Sci. Part A Polym. Chem. 24 (5) (1986) 1019-1026. 

High lEC and high molecular weight linear SPIs can be easily cross-linked in the presence of phosphorus pentoxide/methanesulfonic acid (PPMA) or phosphorus pentoxide. Two different ways were recently described by Okamoto and his group ... 

Eaton, P.E., Carlson, G.R., Lee, J.T. (1973) Phosphorus pentoxide-methanesulfonic acid convenient alternative to polyphosphoric add. The Journal of Organic Chemistry, 38, 4071 073. 

Vinylcyclobutanones may be converted to cyclohex-2-enones 1 on treatment with Eatons reagent (methanesulfonic acid/phosphorus pentoxide).69 The yields are usually only moderate due to a side reaction leading to cyclopentenones. This side reaction is especially important for 2,2-disubstituted cyclobutanones (R3 4 H).69 In all cases the carbonyl group migrates to the /(-position of the double bond. 

The same mode of migration is found if the rc-bond needed for rearrangement is part of an aryl ring in the 2-position. Usually only the substituted C3 of cyclobutanones (Table 5)71 74,140 or cyclobutanols (Table 6)75 migrates on treatment with trifluoroaeetic acid,73 methanesulfonic acid,71 trifluoromethanesulfonie acid, 140/ -toluenesulfonic acid,74 phosphorus pentoxide,71-74 and tin(IV) chloride,72 generally with diethyl ether or benzene as the solvent. 

NaNC>3 and cone. H2SC>4 gave 5-chloro I-nitrobenzo[2,l,3]selenadiazole 142 in 90% yield (Equation 7) <2004RJC428>. An improved method for nitration of fluorine-substituted benzo[2,l,3]selenadiazoles was also reported. Treatment of a variety of benzo[2,l,3]selenadiazoles with commercially available 90% nitric acid dissolved in a mixture of methanesulfonic acid and phosphorus pentoxide at room temperature gave 4-nitrobenzo[2,l,3]sclc-nadiazoles in 81-94% yield <2004JHC1023>. The obtained 2,1,3-benzoselenadiazoles were used as precursors to o-phenylenediamines (see Section 6.12.5.8). 

Carboxy-l-organoethen-l-yl tellurium compounds are converted to 4-oxo-4H-1-benzotellurins by treatment with phosphorus pentoxide in methanesulfonic acid1. 

Methoxy-4-oxo-4//- 1-bcnzotellurinh 1.20 g (3.92 mmol) of 2-carboxyethenyl 3-methoxyphenyl tellurium are added to a solution of 1 g of phosphorus pentoxide in 10 ml] of distilled methanesulfonic acid and the resultant mixture is stirred at 20° for 4 h. 250 ml] of saturated aqueous sodium hydrogen carbonate solution are then added dropwise, the mixture is extracted with three 50 ml] portions of dichloromethane, and the combined extracts are dried with anhydrous sodium sulfate, filtered, and concentrated. The residue is recrystallized from methanol yield 0.76 g (67%) m.p.103°. 

The indanone oximes (7) gave the aryl- and alkyl-migrated products (8) and (9) (equation 6), with the proportion of (9) itKteasing with increasing steric demand of arenc substituents at the 4- and 7-positions. Exposure of the ( )-oxime (10) to phosphorus pentoxide and methanesulfonic acid gave the product (11) of migration of the yn-alkyl group, presumably via the (Z)-isomer (equation 7). 

Analogously, 2-ethynyl-2-methylcyclobutanone (24) was obtained in 83% yield from the corresponding alcohol 23 upon treatment with methanesulfonic acid and phosphorus pentoxide in diethyl ether at 25 °C. 

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