Chlorzoxazone

Nitration of phenolic compounds by metal salts impregnated Yb-Mo-montmorillonite KSF

“…1 Nitration of aromatic compounds is one of the most important industrial processes [2][3][4][5][6][7][8][9] and is the subject of a large body of literature. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] In our laboratory, we have been seeking out a more practical process for the nitration of substituted phenols using stoichiometric or a small excess amount of nitric acid under mild conditions because the development of environmentally friendly practical procedures for the nitration of aromatic compounds is highly desirable. [24][25][26][27] However, in our previously reported nitration processes for phenolic compounds, 500 mg of KSF for 1.0 mmol of phenolic compounds must be required to give the nitrated products in good yields.…”

A New Method for Nitration of Phenolic Compounds

“…A particular case is that in the nitration of phenol, a mixture of 2-nitrophenol and 4-nitrophenol is usually formed. However, since the concentration of nitronium ions (NO 2 ) present in dilute nitric(V) acid is very small, the NO 2 ion is unlikely to play a significant part in the nitration process. There is evidence that the electrophile involved is the nitrosonium ion (NO ), namely, the electrophilic substitution of a hydrogen atom with À NO group is a major reaction path.…”

“…There is a large body of literature so far. Using HNO 3 , AgNO 3 , NaNO 3 or Ca(NO 3 ) 2 as an NO 2 carrier and H 2 SO 4 or BF 3 as an acid catalyst in CH 3 CN, CHCl 3 or aromatic solvents, the nitrated phenolic compounds were obtained in good yields.…”

“…[5] Some other methods, for example, using Cu(NO 3 ) 2 /K10 as a catalyst and 100% HNO 3 as an NO 2 carrier in acetic anhydride are also useful in the nitration of phenolic substrates. [6] In addition, Fe(NO 3 ) 3 ¥ 1.5 N 2 O 4 , Cr(NO 3 ) 3 ¥ 2 N 2 O 4 and Cu(NO 3 ) 2 ¥ N 2 O 4 can be used as NO 2 carrier in this nitration reaction.…”

“…[6] In addition, Fe(NO 3 ) 3 ¥ 1.5 N 2 O 4 , Cr(NO 3 ) 3 ¥ 2 N 2 O 4 and Cu(NO 3 ) 2 ¥ N 2 O 4 can be used as NO 2 carrier in this nitration reaction. [7] Recently, the nitration of phenol with 6 wt % nitric acid in the presence of a phasetransfer catalyst has also been reported.…”