Benzylamides

Heat together under reflux i g. of the ester, 3 ml. of benzylamine and 0 15 g. of ammonium chloride for J hour. Cool, add about 10 ml. of water to dissolve up the excess of benzylamine and filter off the benzylamide. Recrystallise from ethanol and take the m.p. 

D) N-Benzylamides. Ammonium salts are readily converted into the... 

C) N-Bensylamides. Amides readily react by interchange with R CONH2 + H.,N CH2CaH5 R CO NH CHgCaHs benzylamine to give benzylamides. 

Ammonium Salts. Benzylthiouronium salts (p. 360), Acids if aromatic (p. 360), Benzylamides (p. 360). 

H-Benzylamides of acids from esters. Esters are converted into the A-benzylamides of the corresponding acids by heating with benzylamine in the presence of a httle ammonium chloride as catalyst ... 

N-Benzylamides are recommended when the corresponding acid is liquid and/or water-soluble so that it cannot itself serve as a derivative. Phe benzylamides derived from the simple fatty acids or their esters are not altogether satisfactory (see Table below) those derived from most hydroxy-acids and from poly basic acids or their esters are formed in good yield and are easily purified. The esters of aromatic acids yield satisfactory derivatives but the method must compete with the equally simple process of hydrolysis and precipitation of the free acid, an obvious derivative when the acid is a solid. The procedure fails with esters of keto, sul phonic, inorganic and some halogenated aliphatic esters. 

If the ester does not yield a benzylamide by this procedure, convert it into the methyl ester by refiuxing 1 g. for 30 minutes with 5 ml. of absolute methanol in which about 01 g. of sodium has been dissolved. Remove the methanol by distillation and treat the residual ester as above. 

The melting points of the N-benzylamides are collected in the following Table ... 

The hydrazides are often crystalline and then serve as useful derivatives. Esters of higher alcohols should be converted first to the methyl esters by boiling with sodium methoxide in methanol (see under AT-benzylamides). 

Ceric ammonium nitrate (CAN), CH3CN, H2O, rt, 12 h, 96% yield. - Benzylamides are not cleaved under these conditions. 

Ceric ammonium nitrate (CAN), CH3CN, H2O, it, 12 h, 96% yield. Benzylamides are not cleaved under these conditions. Some of the methods used to cleave the benzyl group should also be effective for cleavage of the PMB group. Ceric ammonium nitrate is also used to cleave the PMB group from a sulfonamide nitrogen. ... 

Benzyl-l,3-dioxo-l,2,3,4-tetrahydro-j8-carboline (189) was prepared by heating the benzylamide 188 with polyphosphoric acid on a... 

A- [(Acy loxy )methyl] derivatization was also examined for its potential to improve the biological stability of peptides. For example, the peptide-like model A-[(benzyloxy )carbonyl]glycine benzylamide (8.171, R = H) was de-rivatized to a few N-/Yacyloxy)methyl] derivatives whose chemical and enzymatic hydrolysis was investigated [225], The results compiled in Table 8.13 indicate a fast chemical hydrolysis, the mechanism of which is depicted as Reaction b in Fig. 8.21. Enzymatic hydrolysis also occurs in human plasma, resulting in short half-lives, with the exception of the pivaloyl analogue. 

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