Aryl chloroformates phenyl chloroformate

Fukuyama and coworkers have synthesized [(2-isocyano-2-methyl)-propyl-l-]-phenyl-carbonate by a modification of the Lindhorst and Ugi protocols. Instead of using alkyl chloroformate to capture the lithium alcoholate lo, they used aryl chloroformate (phenyl chloroformate) to obtain Ir (Scheme 7.48) [65]. The phenyl analog is odorless and stable under chromatographic separation. 

During the preparation of aryl chloroformates, it is essential to keep the reaction mixture really cold during water washing to prevent vigorous decomposition. Phenyl and naphthyl chloroformates may be distilled, but benzyl chloroformate is too thermally unstable. 

Attempts to apply the thermal decarboxylation reaction in the liquid phase to aromatic halofor-mic acid esters have shown that their reaction is different from that ol the aliphatic haloformates. It was found that evolution of carbon dioxide occurs, but only high boiling products could be isolated.136 On heating in the presence of aromatics and Lewis acids, aryl chloroformates do not react to give chlorinated aromatics with concomitant decarboxylation, but undergo a Friedel-Crafts reaction to give phenyl benzoates.137 Under similar conditions phenyl fluoroformate undergoes only polymerization and carbonate formation.137... 

Oxidation of iV-phenyl-2-(arylcarbamothioyl)hydrazinecarboxamides 71 and benzyl iV-aryl-2-(phenylcarbamoyl)-hydrazinecarbimidothioates 73 with bromine in water-moistened chloroform resulted in the formation of l-aryl-2-phenyl-6-thioxo-l,2,4,5-tetrazinan-3-ones 72 and 6-(benzylthio)-5-aryl-4-phenyl-4,5-dihydro-l,2,4,5-tetra-zin-3(2//)-ones 74, respectively (Scheme 18) <1998IJH173>. 

Peroxybenzoic acid readily oxidizes aryl and alkyl sulphoxides in acetone, methylene chloride or chloroform solutions, to the sulphone in high yield . The reaction is second order and acid catalysed as is the reaction with peracetic acid . The rate of oxidation is about five times faster than when peracetic acid is used. Other work considering the oxidation of sulphoxides with peracids gathered kinetic evidence and showed that the reaction was indeed second order and that the reaction involved nucleophilic attack by the sulphoxide sulphur atom on the peracid moiety. A further study by the same authors showed that with benzyl and phenyl alkyl sulphoxides the rate of reaction was very sensitive to the inductive effect of the alkyl group. Support for the nucleophilic attack by the sulphur atom on the peracid in acidic solution was forthcoming from other sources . ... 

Transport of amino acids across a chloroform liquid membrane with these carriers also revealed a high specificity (Scheme 2). For efficient transport, an aromatic side chain must be present and the distance between the aryl and ammonium functions is optimal in the P-aryl systems. Neither oe-phenyl-glycine 42 nor y-phenyl-butyrine 43 are transported to significant extents 25a>. These results are shown in Table 2. The selectivity with 13 contrasts sharply for that observed with typical detergents wherein side chain hydrophobicity determines the relative transport rates. 

Another Pd-catalyzed reaction of aryl- and alkylzinc halides used carboxylic anhydrides as starting organic compounds (Scheme 127).328 One of the advantages of this method is that anhydrides can be synthesized in situ from the corresponding sodium salts of carboxylic acids and ethyl chloroformate. The scope of the method includes aliphatic and aromatic anhydrides, phenyl-, ethyl-, isopropyl-, and n-butylzinc iodides. 

A screening of (R)-bis-N-tosyl-BlNAM 151 and axially chiral (thio)urea derivatives 152-162 (10mol% loading 0.36 M catalyst concentration incorporating the N-aryl(alkyl) structural motif was performed at various reaction temperatures in di-chloroform using the asymmetric FC addition of N-methylindole to trans-Ji-nitrostyrene as model reachon (product 1 Scheme 6.158). The structure of bis(3,5-bistrifluoromethyl) phenyl functionalized binaphthyl bisthiourea 158 was identified... 

The reaction of arylthioamides (248) with phenylisocyanate affords the arenethiocarboxamide (249), which can be benzylated to give (250) and then converted into 5-aryl-3-oxo-2-phenyl-1,2,4-thiadiazoline (251) on treatment with bromine in chloroform. Alternatively, (249) can be transformed into (251) by direct oxidation with bromine (Scheme 56) <85IJC(B)977>. 

The UV spectra of 1,2-thiazetidinone oxides have been recorded by Beeken and Korte. Measured in cyclohexane or chloroform, the N-substituted cyclohexyl- (35), phenyl-, and aryl-substituted 4,4-bisphenyl-l,2-thiazetidin-3-one 1,1-oxides showed an average absorption band at = 240 nm... 

A modification of the Pomeranz-Fritsch synthesis <1983JCXI3344> is used in the preparation of thieno[2,3- l-pyridine and its 2-substituted derivatives. An aryl aldehyde undergoes condensation with aminoacetaldehyde dimethyl acetal giving a Schiff base which cyclizes to form an imine product. The imine is treated with ethyl chloroformate followed by triethyl phosphate to form an intermediate carbonate-phosphonate, which then cyclizes to the thienopyr-idine product (Scheme 22) <2004S1935>. Very low product yields (2-17%) are obtained for alkyl- and phenyl-substituted thieno[2,3- ]pyridines however, the unsubstituted product and 2-halogenated derivatives give moderate yields (28-44%). 

E-values of similar magnitudes can also be obtained with other 3-aryl-2-methylpropan-l-ols Aryl = phenyl, Amano PS/vinyl acetate/chloroform, E = 116... 

Isoflavones.2 Treatment of the flavanone 1 with TTN in methanol/chloroform containing perchloric acid (essential) results in an isoflavone (2) as the major product, formed via a 2,3-aryl migration. Substitution of a halogen group at the para-position of the phenyl group increases the yield of the isoflavone. 

The synthesis of the first alkynyliodonium tosylates was achieved by the treatment of terminal alkynes with [hydroxy(tosyloxy)iodo]benzene (HTIB) (equation 8)8,10,11. Such reactions are generally conducted with an excess of alkyne in chloroform at reflux, although they can be carried out at room temperature, and dichloromethane can be employed as solvent. This procedure is, however, restricted to terminal alkynes in which R is either an aryl group or a bulky alkyl group. With linear alkyl groups (i.e. R = n-Pr, n-Bu, fl-C5Hn), phenyl(/ -tosyloxyvinyl)iodonium tosylates are obtained instead (equation 9)8. In some cases (R = /-Pr, /-Bu), mixtures of alkynyl- and (/ -tosyloxyvinyl)iodonium tosylates are produced8. ter -Butylacetylene appears to be the optimum substrate for this approach and has been employed with a series of [hydroxy(tosyloxy)iodo]arenes for the synthesis of various aryl(ter/-butylethynyl)iodonium tosylates (equation 10)9. 

Methylphenylimino)methyl]phenyl Tellurium Bromide4 A solution of 1.60 g (10 mmol) bromine in 40 m/ chloroform are added dropwise to the vigorously stirred solution of 3.80 g (10 mmol) butyl 2-(4 -melhylphenylimino)melhylphenyl tellurium in 40 ml chloroform. The mixture is heated to the boiling point and then cooled. The mixture is filtered to remove a small amount of the aryl tellurium trihromide. The filtrate is concentrated to 20 ml and then mixed with 20 ml dry diethyl ether. The yellow crystals are collected by filtration, washed with diethyl ether, and dried yield 92% m.p. 170°. 

Addition of aryl tellurium trihalides to cyclohexene produces trails-] -aryldihalotelluro-2-halocyclohexanes when the reactions are carried out in chloroform, and trans-1-aryldihalotelluro-2-methoxycyclohexanes when methanol is used as the reaction medium. Treatment of the 2-chlorocyclohexyl 4-methoxyphenyl tellurium dichloride with terf.-butyl hydroperoxide in acetic acid yielded tram-l,2-dichlorocyclohexane and aryl chloride. Bis[4-methoxyphenyl] tellurium dichloride did not yield any aryl chloride under these conditions1. Pyrolysis of tran.s-2-methoxycydohexyl phenyl tellurium dibromidc afforded Crum- l-bromo-2-methoxycyclohexane1. 

An alternative common method of nitrile oxide synthesis, frequently referred to as the Mukaiyama method (60JA5339), involves dehydration of primary nitroalkanes using, for example, phenyl isocyanate in the presence of a catalytic amount of triethylamine (Scheme 5). Phosphorus oxychloride (730S59 90S817), chloroformate esters (86BCJ2827), aryl... 

One-electron oxidation of phenyl iron(III) tetraarylpor-phyrin complexes with bromine in chloroform at —60°C produces deep red solutions whose H and H NMR spectra indicate that they are the corresponding iron(IV) complexes. For the low-spin aryl Fe porphyrins the electron configuration is (dxyf(dxz,dyzf, with one tt-symmetry unpaired electron, and for the low-spin aryl Fe porphyrins the electron configuration is d, yf- d, zAyzf with two TT-symmetry unpaired electrons. The aryl Fe porphyrins are thermally unstable, and upon warming convert cleanly to A-phenylporphyrin complexes of Fe by reductive elimination. This process has been investigated by electrochemical techniques, by which it was shown that the reversible (at fast scan rates) one-electron oxidation of a-aryl complexes of PFe was followed by an irreversible chemical reaction that yielded the Fe complex of the A-phenylporphyrin, which could then be oxidized reversibly by one electron to yield the Fe complex of the A-phenylporphyrin. (If the Fe complex of the N-phenylporphyrin is instead reduced by one electron, the Fe complex of the A-phenylporphyrin is formed reversibly at... 

Unsaturated aldehydes and amines give ene-1,3-diamines which combine with aryl azides in chloroform to yield, e.g., 4-methylamino-5-methyl-aminomethyl-5-phenyltriazoline from propenal, methylamine, and phenyl azide (25°C, 1-36 hr, 60-90%) [72JCS(P1)619 72JCS(P1)769]. 

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