Reaction of primary amine and urea gave a monosustituent of urea with the evolution of ammonia. The reactiveness of the primary amine with urea was quite different by use of aliphatic and aromatic amines. In the reaction of aliphatic amine and urea, the product was composed entirely of a monosubstituent of urea, while that of aromatic amine and urea gave a monosubstituent as well as a disubstituent of urea.
The reaction of secondary amine and urea gave N, N-disubstituent with the evolution of ammonia, but N, N, N', N'-tetrasubstituent could not be obtained. This is clear from its reaction mechanism and it is not concerned with the reaction velocity. The following three kinds of secondary amines may be considered when R=alkyl group and R'=aryl group: As examples of these, di-n-butylamine, ethylaniline, and diphenylamine were chosen and their reaction with urea have been investigated. The reaction velocities of these secondary amines and urea were in order of An introduction of aryl group caused a rapid decrease in reaction velocity. For this reason, the secondary amines, other than aliphatic secondary amine, gave the formation of cyanuric acid and N, N-disubstituted urea could not be obtained.
Diamines having no substituent group on the nitrogen are primary amines andthose having substituent group are secondary amines. Accordingly, the reaction of diamine and urea can easily be assumed from the reactions of primary amine and urea, and secondary amine and urea. In the reaction of aliphatic diamine and urea, a monosubstituent of urea was obtained almost selectively. Since the disubstituent is very difficult for its formation, a monourea and diurea derivatives of diamine are formed at first, followed by the reaction for formation of disubstituents or polymerization reaction. Also, some of aliphatic diamines form a cyclic compound from the reaction with urea. In this case, the cyclic compound is f romed through the process of formation of high polymer and its depolymerization. In the reaction of aromatic diamine and urea, there are the reactions of formation of a monosubstituent of urea at first, followed by the formation of its disubstituent; in this case, polymerization reaction happens at the same time of formation of monosubstituent of urea. The reaction of secondary diamine and urea gives no polymerization productas it is clear from its reaction mechanism.
Alkylurea reacts with amine to form a disubstituent. On the other hand, arylurea reacts with aliphatic primary and secondary amine by inter exchange reaction of aryl group and alkyl group and gives free aromatic amine. Therefore, for synthesis of N-alkyl-N'-arylurea by the reaction of a monosubstituted urea and amine, it is necessary to introduce alkyl group at first, then the introduction of aryl group is made. For synthesis of N, N', N'-trisubstituted urea, an introduction of the secondary amine at first does not allow the entrance of subsequent introduction of substituent group.
In order to investigate the rate of formation of two kinds of isomer of 4-benzoyl-1, 8-naphthoylenebenzimidazole, obtained from condensation of 4-benzoylnaphthalic anhydride and o-phenylenediamine, synthesis of each of them has been made. 4-Nitro-7 H-benzimidazo [2, 1a] benz (de) isoquinoline-7-on was made through 5-nitro-8-bromo-l-naphthoic acid as a starting material, this was treated for nitrile formation by the reduction, its carboxylation and benzoylation gave 4-benzoyl compound in clear yellow plates with mp. 198-9°c. 3-Benzoyl compound was prepared from condensation of 4-nitronaphthalic anhy dride and o-phenylenediamine in almost a pure form of 3-nitro compound, and this was derived into 3-benzoyl compound in the procedure as above. 3-Benzoyl compound was clear yellow needles with mp 235-6°c.
The rate of formation of 3-benzoyl derivative (3-a) of 7H-benzimidazo[2, 1a]-benz(de)isoquinoline-7-on and its 4-benzoyl derivative (3-b), obtained by condensation of 4-benzoylnaphthalic anhydride (1) and o-phenylenedimine (2), has been investigated. Refluxing of (1) and (2) in ethanol gave N- (o-aminophenyl)-naphthalimide (4). Ref luxing in glacial acetic acid or fusing of (4) gave respectively a mixure of (3-a) and (3-b). The ratio of formation of these two isomers was saught from the melting point curve and it was found that the formation ratio was approximately 1:1, either by ref luxing in glacial acetic acid or by fusion reaction. Also, the separation of mixture of (3-a) and (3 -b), obtained by condensation of (1) with (2) in glacial acetic acid, was possible.