Phenobarbital nitration

However, in contrast to these results, it has also been reported that phenobarbital yields 3-nitrophenyl derivatives as the major products and the presence of 4-nitrophenyl isomers could be demonstrated from spectral data but could not be isolated. The nitration of methyl phenobarbital was reported to form the 4-nitrophenyl derivative and the formation of the 2-nitrophenyl isomer was demonstrated (75MI2). Another early reference quotes that phenobarbital nitrates give the 3-nitrophenyl product (33JA2817 33JA3895). 

Nonelectroactive benzene or toluene can be quantitatively converted to electroactive nitroderivatives. The method can be extended to any polarographic-ally inactive but easily nitrated aromatic compounds such as phenols, phenyl-bearing amino acids, and aniline derivatives. Interesting discriminations between similar compounds based on their ability to be nitrated or not can be achieved. Thus, the readily nitrated phenylbarbituric acid (phenobarbital) can be polarographically determined in the presence of a 100-fold excess of diethylbarbituric acid (barbital). The nitration of morphine also provides an excellent route for the polarographic determination of this otherwise practically nonelectroactive alkaloid. 

Mono- monovalent electrolytes 3.4 1.8 Sodium chloride Silver nitrate Phenobarbital sodium... 

Labeling of phenobarbital, a barbiturate used in the treatment of convulsions, was carried out by acylation of p-aminophenobarbital 15 by the acid chloride of cymantrene 11 (Scheme 8.8). Synthesis of 15 was performed by nitration of the benzene ring of phenobarbital [35] to give a mixture of m- andp-nitrophenobarbital 13 and 14 followed by reduction of p-nitrophenobarbital by hydrogenation in the presence of palladium on charcoal [36]. 

After nitration, phenylethylbarbituric acid (phenobarbital) can be determined in the presence of a hundredfold excess of diethyl-barbituric acid (barbital). 

For Elixir of Phenobarbital, U.S.P. Mix 50 ml of the sample with 50 ml of a 3 per cent solution of anhydrous sodium carbonate. Prepare a blank solution consisting of 7-0 ml of dehydrated ethanol, 50 ml of the 3 per cent sodium carbonate solution, 1 00 ml of 0 01 N silver nitrate and sufficient water to make 100 ml. Determine the potential of the blank solution and titrate the sample solution to this potential. Correct for the blank as before. 

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