Ortho-phenylenediamine

A variation of this method led to the generation of bis-benzimidazoles [81, 82], The versatile immobilized ortho-phenylenediamine template was prepared as described above in several microwave-mediated steps. Additional N-acylation exclusively at the primary aromatic amine moiety was achieved utilizing the initially used 4-fluoro-3-nitrobenzoic acid at room temperature (Scheme 7.72). Various amines were used to introduce diversity through nucleophilic aromatic substitution. Cyclization to the polymer-bound benzimidazole was achieved by refluxing for several hours in a mixture of trifluoroacetic acid and chloroform. Individual steps at ambient temperature for selective reduction, cyclization with several aldehydes, and final detachment from the polymer support were necessary in order to obtain the desired bis-benzimidazoles. A set of 13 examples was prepared in high yields and good purities [81]. 

In a related vein, one of the benzene rings in dibenzepin (36-7) can be replaced by pyridine. In a one-pot reaction, condensation of the 2-chloronicotinic acid (43-2) with ortho-phenylenediamine (43-1) leads to the lactam (43-3). The order in which the two steps, aromatic displacement and amide formation, take place has not been elucidated. Simple alkylation of the anion from the product with 3-chloro-2-(AA -drmethylamino)propane (43-4) affords the antidepressant agent propizepine (43-5) [43]. 

The reaction of peri-butoxyphenalenone 525 or peri-diethoxy-phenalenium borofluoride 526 with ortho-phenylenediamine (OFD) under... 

A solution of or /zo-hydroxybenzalacetone 2 (1.62 g, 0.01 mol) and ortho-phenylenediamine 1 (1.1 g, 0.011 mol) in methanol (30 ml) containing two drops of concentrated hydrochloric acid was refluxed for 1 h (TLC control Scheme A.29). After evaporation of the solvent, the oil formed was chromatographed on silica gel (CHC13) and then compound 3 was crystallized from diethyl ether-light petroleum ether as colorless prisms (0.35 g, 14%). Melting point 126-127°C (dec.). 

A mixture of the appropriate cyclic unsaturated ketone 2(10 mmol) and ortho-phenylenediamine 1 (20 mmol) in 50 ml of ethanol was refluxed for 48 h, the solvent was evaporated under reduced pressure and the residue was crystallized from ethanol to obtain compound 3 (Scheme A.30). 

Nitrobenzimidazolyl-2-amino)-benzothiazoles are obtained from ortho-phenylenediamines and.S, .S -dimethyl-Af-(2-bensothyazolyl)-carbonimido-dithioates in dimethylformamide (Scheme 2.56) [409],... 

Heteropolyacids have been used as recyclable catalysts in the reaction between ortho-phenylenediamines 180 with acid chlorides to yield 1,3,5-benzoxadiazepines 181 in good yield <07MOL255>. 

A phosphorus analog of benzimidazole (2), containing dicoordinate phosphorus, is mentioned as the reaction product between triethylphosphite, P(OEt)3, and ortho-phenylenediamine. ... 

Interaction between the alkaline salts of fluorinated /1-diketones and ortho-phenylenediamine and ortho-diaminonaphthalene forms the corresponding 2-difluoromethyl-4-phenyl-3//-benzo[6]-1,4-diazepines and 2-difluoro-methyl-4-phenyl-3i/-naphtho[2,3-6]-l,4-diazepines (87GEP3603291) (Scheme 42). 

In 1996, the condensation of orthoesters with ortho-phenylenediamine leading to benzimidazoles was achieved in toluene under reflux or without solvent by use of focused microwaves (Scheme 10.82) [162]. 

Add chromophore/substrate. This could be any of the ones described in Chapter 3 added with due care as to accuracy and checks on the pHs of the buffers involved. In this example, we shall assume we add H202/ortho-phenylenediamine (OPD) at 50 pL/well (in every well of the plate). 

In practice, aliphatic diamines are less useful than ortho-diaminobenzenes (also called ortho-phenylenediamines), and the reaction is best known as a synthesis of benzopyrazines (quinoxalines. Scheme 4.9). 

The products are known as benzimidazoles. The reactants are ortho-phenylenediamine derivatives and aliphatic adds in a refluxing HCl solution. The reaction is shown in a reasonable mechanistic form in Scheme 4.24. Here, it is proposed that an amino group displaces OH from the acid to form an amide (4.25), which is a known process. Amide carbonyls do not generally behave in the way aldehyde and ketone carbonyls do, but nevertheless it has been suggested that the second amino group does add to the amide carbonyl, with dehydration of the adduct, to form the double bond in the imidazole ring (4.26). 

Amino-substituted bis-A-thiocarbamoylbenzotriazole 196 was readily obtained by milling of 2 equiv. of bis(benzotriazolyl)methanethione 189 with 1 equiv. of para-phenylenediamine. On the other hand, analogous synthesis starting from ortho-phenylenediamine and 1 equiv. of 189 yielded bisthione 198 as a result of an intramolecular cyclization (Scheme 3.51). 

Depending on the degree of exposure, regular medical checkups are advis le. Lung edema symptoms usually develop several hours later and are aggravated by physical exertion rest and hospitalization essential. As first aid, adoctor or authorized person should consider administering a corticosUroid spray. The measures on this card also apply to meta and ortho phenylenediamine. 

Chloro-ortho-phenylenediamine p-Chloro-o-toluidine p-Chloro-o-toluidine, strong acid salts of... 

Saloutin VI, Bazyl IT, Skryabina ZE, Shurov SN, Perevalov SG (1995) Interaction of 5,6,7,8-tetrafluoro-2-ethoxycarbonyl(carboxy)chromones with hydrazine and ortho-phenylenediamine. Zhurn Organ Khim 31 718-725... 

Mamedov VA, Polushina VL, Mertsalova EF, Nuretdinov lA, Plyamovatyi AKh (1991) Medium effect on the direction of the reaction of 3-chloro-l,3-diphenyl-1,2-propanedione with ortho-phenylenediamine. Bull Rus Acad Sci Div Chem Sci 40(7) 1472-1474. doi 10.1007/ BF00961256... 

Adeloju SB, Sohail M (2011) Polypyrrole-based bilayer nitrate amperometric biosensor with an integrated permselective poly-ortho-phenylenediamine layer for exclusion of inorganic interferences. Biosens Bioelectron 26(ll) 4270-4275. doi 10.1016/j.bios.2011.04.002... 

A series of reaction for the synthesis of 2-aryl-1-arylmethyl-lH-1, 3-benzimidazoles from ortho phenylenediamine and aromatic aldehydes in the presence of montmorillonite K-10 under microwave irradiation in the absence of solvent with good yields has been reported (Perumal et al., 2004). 

On reaction with two mols formaldehyde in neutral solution aromatic orthodiaxoines, such as ortho-phenylenediamine and 1,2-diaminonaphtha-lene, give products whose empirical formulas correspond to the dimers of the respective Schiff bases. In weakly acid solution, diamines. such as 1,3,4-toluylenediamine give imidaaoles. ... 

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