Nitration Benzotriazoles

Electrophilic substitution reactions only occur at the benzene part of benzotriazole. Nitration gives mainly the 4-nitro compound, whereas chlorination with concentrated HCl/ HNO3 yields 4,5,6,7-tetrachlorobenzotriazole. 

Nitration of a series of mesomeric betaines was extensively studied in connection with their potential use as explosives (Scheme 3). Nitration of l,2,3-triazolo[2,l- ]benzotriazole 74 can be achieved selectively, occurring first at the 7-position which is followed by nitration at the 3- and 5-positions. Thus, nitration with 45% nitric acid gives a mixture of 7-nitro derivative 75 (39%) and dinitro derivative 76 (58%), while 70% nitric acid yields a mixture of 3,7- (52%), 5,7- (23%), and 3,5-dinitro (5%) isomers 76-78. Clean trinitration to 3,5,7-trinitro-l,2,3-triazolo[2,l- ]benzotriazole 79... 

A similar complex 80 is also produced in a reaction of cobalt(ll) nitrate with potassium tricyanomethanide (Ktcm) and benzotriazole (BtH). According to the X-ray data for this complex, the CoN6 octahedron is only slightly distorted, having the N-Co-N angles in the range of 88.37-91.16°. The equatorial Co-N(tcm) distances (2.106 and 2.110 A) are... 

Treatment of benzimidazole with ozone and N02 results in a complex mixture of mono- and di-nitrated benzimidazoles and triazoles. However, nitration of 5-nitrobenzimidazole 1209 under such conditions leads to two major products, benzotriazoles 1210 and 1211. The mechanism of ring conversion from benzimidazole to benzotriazole is not clear (Equation 29) <2004CPB570>. 

To get a complex set of substituents by direct derivatization of benzotriazole is not feasible. In such situations, it is better to have all the substituents in place first and later construct the heterocyclic ring. High reactivity of anilines and their well-developed chemistry makes them good stating materials. In an example shown in Scheme 215, acetanilide 1288 is nitrated to afford nitro derivative 1289 in 73% yield. Catalytic reduction of the nitro group provides methyl 4-acetylamino-3-amino-5-chloro-2-methoxybenzoate 1290 in 96% yield. Nitrosation of compound 1290 in diluted sulfuric acid leads to intermediate 1291, which without separation is heated to be converted to 7-chloro-4-methoxy-l//-benzotriazole-5-carboxylic acid 1292, isolated in 64% yield <2002CPB941>. 

Ammonium hexacyanoferrate(II), 2577 f Arsine, 0100 Azido-2-butyne, 1473 3-Azidopropyne, 1114 c /.v-A/obcn/cnc, 3484 Azoxybenzene, 3485 Barium azide, 0214 Benzenediazonium nitrate, 2275 Benzotriazole, 2269 Borane, 0135 Bromine azide, 0256 f 3-Bromopropyne, 1090 f 1,2-Butadiene, 1479 f 1,3-Butadiene, 1480 f Buten-3-yne, 1423 f 1-Butyne, 1481 f 2-Butyne, 1482 Cadmium azide, 3957 Cadmium cyanide, 0588 Cadmium fulminate, 0589 Cadmium nitride, 3960... 

Benzol hjthiophene, see Naphthalene 1,2,3-Benzotriazin-4 (3/J -one, see Azinnhos-methyl Benzotriazole, see Tetrachloroethylene Benzyl alcohol, see Benzo[a]anthracene, Benzyl butyl phthalate. Benzyl chloride, Permethrin. o-Xylene, m-Xylene, p-Xylene. Toluene 0-Benzyl alcohol, see o-Xylene m-Benzyl alcohol, see m-Xylene p-Benzyl alcohol, see p-Xylene 10-Benzyl-10-hydroanthracen-9-one, see Benzo [ a] anthracene Benzyl hydroperoxide, see Toluene Benzyl nitrate, see Toluene Benzylsuccinic acid, see Toluene... 

The chlorine atom in a-chloroalkylbenzotriazoles (560) undergoes exchange with other halogen atoms (Scheme 108). Thus, treatment of (560) with KF in the presence of 18-crown-6 gives the fluoro derivatives (561) <93PJC1243>. Sodium bromide or sodium iodide reacts with (560) to form (559, X = Br, I), whilst treatment of (560) with silver nitrate produces benzotriazol-l-ylmethyl... 

A subcategory of dopamine receptor antagonists has found some use as antiemetic agents administered in conjunction with antimmor chemotherapy. The preparation of one of these agents based on a benzotriazole nucleus begins with nitration of the amino salicylate ester (67-1). Catalytic hydrogenation of the product (67-2) leads to the orf/zo-diamine (67-3). Treatment of this last product with nitrous acid... 

Note No higher nitrated derivs of Benzotriazol-ols were found in Beil or in CA thru 1956... 

On nitration of unsubstituted benzotriazole the nitro group enters into the position 4(7) [43, 250-254], 6(5)-Methyl-5,7(4,6)-dinitrobenzotriazole has been synthesized by nitration of 6(5)-methyl-7(4)-nitrobenzotriazole under thermal conditions... 

Under nitration, benzotriazolyl-2 acetic acid gave only one 4-nitro isomer [270], The same results were achieved with the nitration of 2-(4-nitrophenyl)benzotriaz-ole [271], Structure of the nitration products of some benzotriazoles has not been determined till the present time [272],... 

Quantum chemical studies (MP2/cc-pVDZ treatment) of the reactivity of benza-zoles indicate the preferred nitration of benzotriazoles and their protonated cations into the 4- and/or 7-position that is in good agreement with the experiment [43],... 

So-called Kyodai nitration - a novel methodology of nitration with nitrogen dioxide and ozone - has been applied to several benzimidazoles with formation of 1-nitrobenzimidazoles and following conversion to 1-nitrobenzotriazoles [275], The nitration of benzotriazole /V-oxide with dilute nitric acid gives the 7-nitro derivatives, whereas nitration with a mixture of nitric and acetic acids leads to 5-nitro- and 7-nitro isomers in a ratio of 1 9 [276],... 

Nitrated benzotriazole and benzofurazan were obtained as a result of an interesting rearrangement in the reaction of 5-dimethylaminobenzofuroxan with 2,4-dinitroben-zenediazonium sulfate or with HN02 in H2S04/H20-C2H50H (Scheme 2.137) [671],... 

The nitration of benzazoles is usually effected using concentrated (65%) to fuming (100%) nitric acid generally at temperature between 0 and 5°C. Indazoles are usually nitrated into 5 position, benzimidazoles - as a rule - into 5- or 6-position of the phenylene fragment whereas benzotriazole into position 4 or 7. For the preparation of other nitrobenzazoles the reaction of heterocyclization is used. 

Azidopropyne, 1114 c/.s-Azobcnzcuc, 3484 Azoxybenzene, 3485 Barimn azide, 0214 Benzenediazonium nitrate, 2275 Benzotriazole, 2269 Borane, 0135 Bromine azide, 0256... 

An attempt was made to correct the copper corrosion problem by different types of fuel treatments (25). JP-5 samples were subjected to clay or silica gel filtration, or treatment with activated charcoal to remove the corrosive compounds. None of these treatments was successful. Samples were also treated with barium nitrate (to precipitate out sulfonates), sodium hydroxide (to extract mercaptans), and air bubbling to oxidize the corrosive compounds. These chemical treatments also were unsuccessful. However, JP-5 fuel (which failed the copper corrosion test) passed if benzotriazole, sometimes used to passivate copper surfaces, was added to the fuel in low concentrations (2 ppm) using FSII as a solvent. This technique is effective for reducing jet fuel attack on copper-nickel pipes used aboard aircraft carriers (26). 

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