1.2- Diaminobenzenes

The carbonyiation of o-diiodobenzene with a primary amine affords the phthalimide 501 [355,356]. Carbonyiation of iodobenzene in the presence of (9-diaminobenzene (502) and DBU or 2,6-lutidine affords 2-phenylbenzimida-zole (503)[357, The carbonyiation of aryl iodides in the presence of pentaflnor-oaniline affords 2-arylbenzoxazoles directly, 2-Arylbenzoxazole is prepared indirectly by the carbonyiation of (9-aminophenol[358j. The optically active aryl or alkenyl oxazolinc 505 is prepared by the carbonyiation of the aryl or enol triflates in the presence of the opticaly active amino alcohol 504, followed by treatment with thionyl chloride[359]. 

Aromatic polyamide (aramid) membranes are a copolymer of 1-3 diaminobenzene with 1-3 and 1-4 benzenedicarboxylic acid chlorides. They are usually made into fine hollow fibers, 93 [Lm outer diameter by 43 [Lm inner diameter. Some flat sheet is made for spirals. These membranes are widely used for seawater desalination and to some extent for other process applications. The hollow fibers are capable of veiy high-pressure operation and have considerably greater hydrolytic resistance than does CA. Their packing density in hoUow-fiber form makes them veiy susceptible to colloidal fouling (a permeator 8 inches in diameter contains 3 M fibers), and they have essentially no resistance to chlorine. 

A general route to benzo-2,l,3-selenadiazoles involves the condensation reaction between 1,2-diaminobenzene and selenium tetrachloride. This method has also been used recently for the synthesis of 4,5,6,7-tetrafluoro-2,l,3-benzotelluradiazole (Eq. 2.9) ... 

The chemistry of 1,2,5-thiadiazole systems (RC)2N2S has been extensively investigated. " In addition to the condensation reactions of sulfur halides with 1,2-diaminobenzenes, this ring system is obtained in high yields by the reaction of S4N4 with acetylenes (Section 5.2.6). For example, the reaction of S4N4 with diphenylacetylene produces 3,4-diphenyl-1,2,5-thiadiazole in 87% yield. 

This section will focus primarily on a comparison of these ring systems with their heavier chalcogen analogues. The first selenium derivative benzo-l,2,5-selenadiazole was prepared more than 115 years ago by the condensation reaction of selenium dioxide with 1,2-diaminobenzene (Eq. 11.12) and other benzo derivatives may be prepared in a similar manner. The parent 1,2,5-selenadiazole has also been reported. This reagent has been employed to make the tellurium analogue via treatment with ethylmagnesium bromide followed by the addition of tellurium tetrachloride (Eq. 11.13). ... 

Cf. the formation of o-diaminobenzene from m-aminobromobenzene and of m-diaminobenzene from p-aminobromobenzene by the action of potassium amide in liquid ammonia (unpublished result of G. B. R. de Graaff, W. C. Melger, and H. J. den Hertog). 

Aminoacroleins enter the transamination reaction with 1,2-diaminoethane to furnish bis adduct 217, whereas with 1,2-diaminobenzene they yield the 2 2 macrocyclic adduct 218 (77CZ161). 

Surprisingly, 1,2-diaminobenzene with three molecules of 4-methoxybut-3-en-2-one forms the substitution product 233 (25°C, EtOH, 24 h, yield 90%) instead of the expected (80MI2) aminomethylquinoline (234) or dimethylpyridoquinoline (235) (80MI1 85ZC28). 

Thus, ynaminoketones with 1,2-diaminobenzene form benzodiazepines with retention of the dialkylamino group. The reaction occurs as a nucleophilic addition in the absence of catalysts. With Q, /3-acetylenic ketones 1,2-diaminobenzene reacts in the same manner, but under proton-catalyzed conditions (72LA24). At the same time, ynamines and enynamines furnish with 1,2-diaminobenzene substituted benzimidazoles as aresultof double attack at the acetylene bond(83ZOR926 84ZOR1648). 

A decrease in the basic properties of the reagent in going from 1,2-diaminoethane to 1,2-diaminobenzene leads, in the case of ynaminoketones (X = Me), to the 1,3-orientation of binucleophile and the formation of the benzodiazepines 356, suggesting that the carbonyl group is also involved in the heterocyclization. 

Ynaminocarboxylates (X = OMe) react with 1,2-diaminobenzene in the same way to form benzodiazepine 386 (88ZOR2321). 

Benzimidazoles are generally synthesized from ortho-diamino-benzenes and carboxylic acid derivatives. The antihistaminic agent, clemizole (60), for example, can be prepared by first reacting ortho-diaminobenzene (57) with chloroacetic acid to form 2-chloro-methylbenzimidazole (58). Displacement of the halogen with pyro-... 

Diamant-glanz, m. adamantine luster, -kitt, m. diamond cement. -mOrser, m, diamond mortar (small steel mortar), -pulver, n. diamond dust, -schwarz, n. diamond black, -spat, m. adamantine spar (corundum). -Stahl, m, very hard steel, tool steel, Diamido-. diamino-, diamido- (see Amido-), -benzol, n. diaminobenzene, -toluol, n. diaminotoluene. 

Diaminobiphenyl (former name benzidine) can be easily bisdiazotized, but is not cleanly monodiazotized by reaction with one equivalent of a nitrosating agent. However, 4-aminobiphenyl-4,-diazonium ions are formed in a triazene equilibration of a 1 1 mixture of 4,4 -diaminobiphenyl with biphenyl-4,4 -bisdiazonium salts in aqueous HC1 (Tauber, 1894 see also Sec. 13.4). Methods for mono- and bisdiazotiza-tion of 1,4-diaminobenzene (/ -phenylenediamine) have been described by Saunders and Allen (1985, p. 29 see also Sec. 2.2). 

If an aromatic o-diamine such as 1,2-diaminobenzene (2.24) is diazotized in dilute aqueous acid, the 2-aminobenzene-l-diazonium ion formed first (2.25) undergoes a rapid intramolecular N-azo coupling reaction to give 1,2,3-benzotri-azole (2.26). Both amino groups of 2.24 can, however, be diazotized in concentrated acid (Scheme 2-18), forming the bis-diazonium ion 2.27. 1,3- and 1,4-diamines must also be bisdiazotized in concentrated acids in order to avoid inter-molecular N- or C-coupling. 

Imino analogues of quinone diazides were studied quite early by Morgan and his coworkers (Morgan and Upton, 1917, and references cited therein). A-monoacylated 1,4-diaminobenzenes were successfully diazotized starting with 4-benzenesulfon-... 

A similar ambiguity concerning structure appears to arise for 1,4-imidoquinone diazides (4.6), which were synthesized many years ago by Dimroth et al. (1917) and by Morgan and Upton (1917), and were reinvestigated by Kazitsyna et al. (1965, 1967, 1968a). Such compounds are obtained by diazotization of 4-aminodiphenylamine and mono-acylated or -formylated 1,4-diaminobenzenes. Under the influence of the... 

In intramolecular N-coupling the diazonio group interacts with a nitrogen-containing substituent in the ortho-position of the aromatic ring. This is the cause of the difficulties in the diazotization and bisdiazotization of 1,2-diaminobenzene (6.45,... 

The reaction also proceeds readily with A/-monosubstituted 1,2-diaminobenzenes (6.45, R = alkyl, aryl, acyl). Kroupa and Matrka (1970) investigated optimal reaction conditions for the synthesis of 1,2,3-benzotriazole from 1,2-diaminobenzene. 

Phenylethenyl group 154 f. Phenylenediamines, see Diaminobenzenes Phosphorescence of diazonium ions 83, 278 Photolysis of diazonium ions 190ff., 277ff., 283ff., 302... 

I, 3-diaminobenzene, 2-iodoaniline, and 2,5-diiodo-4-aminotoluene in hydrochloric acid containing stannous chloride the respective rate coefficients were... 

Which of the following isomers of diaminobenzene can form chelating complexes Explain. 

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