Benzothiazole 6- nitro

Benzothiazole, 3-methyl-N-ethyl-N-(3-cyanoethyl)aniline-4,2 -azo-6 -nitro-visible, 1, 343 <67MI11201)... 

Benzothiazin-4-ones, dihydrosynthesis, 3, 1028 Benzothiazole, acetoacetylamino-azo pigments from, 1, 334 Benzothiazole, 2-acyl-synthesis, 6, 265 Benzothiazole, 2-alkoxy-synthesis, 6, 323 Benzothiazole, 2-alkyl-synthesis, 6, 265 Benzothiazole, 2-alkyl-6-nitro-reactions... 

Benzothiazole, 2-methyl-2-phenyl-2,3-dihydro-synthesis, 6, 325 Benzothiazole, 2-nitro-reactions, 6, 285 Benzothiazole, 5-nitro-nucleophilic attack, 5, 62 reactions... 

Low yields (9 0%) of 4-nitro-3//-benzothiazole-2-thiones 74 were obtained by treatment of the corresponding dinitroanilines 73 in DMF with carbon disulfide in the presence of sodium hydride (Eq. 10) (81JHC1597). 

Most recent syntheses of fluorinated benzothiazoles make use of nucleophilic substitution. Potassium fluoride in acetonitrile converted 40 into the 2-fluoro derivative (R = 6-nitro) in 99% yield. When the solvent was dimethylformamide the 2-dimethylamino derivative was formed instead [80JCS(P1)2358], and similar behavior was reported earlier (77BSF171). 

Nitro-l-thiocyanato-benzol liefert bei der Elektrolyse an Quecksilber-Kathoden (in 0,5 nHCl) bis 88% d. Th. 2-Amino-1,3-benzothiazol-3-oxidl. An Blei-Kathoden wird als Hauptprodukt 2-Amino-l, 3-benzthiazol neben 2-Amino-thiophenol1 2, an Kupfer-Ka-thoden ausschlicBlich 3-Amino-4-thiocyanato-phenol gebildet. 

Under the influence of ultraviolet irradiation, chloride displaced the nitro group of 2-(5 -nitro-2 -furanyl)benzothiazole to give a chlorofuran exhibiting intense violet fluorescence. This allowed the reaction to be used as an analytical process for chloride determination (80CPB939). 

The 1,2-hydrogen shift isomers of neutral (singlet and triplet) thiazole and its radical cation have been investigated87 by a combination of mass spectrometric experiments and hybrid density functional theory calculations. An unexpected isomerization of A-aryl-3-amino-4-nitroisothiazole-5(2//)-imines (71) to 2-(benzothiazol-2-yl)-2-nitro-ethene-1,1-diamines (72) has been reported.88... 

Like 1,2-benzoselenazole [163], 1,2-benzothiazole [164-166] on heating forms a mixture of 5-nitro- and 7-nitro isomers (Scheme 2.17). 

The introduction of substituents into the position 3 does not change the reaction course [165, 167-169], 4-Amino-7-nitrobenzisothiazole in the sulfuric-nitric mixture forms 5,7-dinitro derivative in low yield [170], 4-Chloro-7-nitro-l,2-benzisothiazole was obtained as a result of the nitration of 4-chloro-l,2-benzisothiazole [171,172], 5-Hydroxy-l,2-benzothiazole is nitrated to the position 4, and in case of 5-hydroxy-4,6-dibromo-l,2-benzisothiazole a substitutive nitration to form 5-hydroxy-6-bromo-4-nitro isomer occurs [173],... 

Nitrobenzothiazole chromophores [588, 589] and their precursors [590] are building blocks of nonlinear optical materials, which are extensively used in the field of optical information processing, optical sensing, data storage, and telecommunications [588, 591], 5-Nitro- [590] and 6-nitro-2-(methyamino)benzothiazole [589] have been prepared from 3-nitro- and 4-nitrophenylthiourea correspondingly, as illustrated in Scheme 2.105. 

Some differences in the change of 13C NMR chemical shifts of nitrobenzothiazoles compared with nitrobenzimidazoles and nitrobenzoxazoles have been discussed. In Table 3.30 the 13C NMR chemical shifts of nitrobenzothiazoles are presented. The nitro group introduction into position 2 leads to a 10 ppm down field shift of the ipso-carbon resonance, whereas a similar effect of the ipso-substitution in the phenylene fragment of benzothiazoles is 20 ppm [778-781], The results of regression analysis of the 13C NMR chemical shifts of benzothiazoles in terms of the inductive and resonance constants of substituents (F and R, c, and cR, c, and aR°) provide evidence for the fact that the substituent effect transmission from positions 2-6 is approximately 30% weaker than in the opposite direction [779], As stated previously, an analogous picture is observed for benzimidazoles. 

The radical anions of five isomers of nitrobenzothiazole (4-N02-, 5-N02-, 6-N02-, 7-N02- and 2-N02-) have been obtained by electrochemical reduction in DMSO and easily characterized by ESR spectroscopy [889], To the contrary, the chemical reduction in alkaline solution (t-BuOK in DMSO or glucose and MeOK in MeOH) presented some problems with 6-N02- and 4-N02-benzothiazoles, and 2-N02-benzothiazole did not provide any detectable paramagnetic species [889], Copper(II) complexes of 6-nitrobenzothiazole-A-sulfonamides as protective agents against superoxide anion have been investigated by ESR spectroscopy [890], The ESR spectrum of 5-nitro-2,l,3-benzothiadiazole RA obtained by electrochemical generation in DMF was reported [886], Unfortunately, the HFS constants of this radical anion are absent and we estimated the HFS constants from simulated spectrum (Table 3.40). 

Mononuclear and dinuclear Cu(II) complexes of TV-substituted nitrobenzothiazole-sulfonamides [214], alkylation products of 2-amino-6-nitro-benzothiazole [795] have been studied by UV visible spectroscopy. 

Dipole moments, static averaged polarizabilities and hyperpolarizabilities of thiazole, benzothiazole, and their dipolar nitro and amino derivatives possessed... 

Flash photolysis of misonidazole, metronidazole, and nitrobenzothiazoles has been carried out in [1369-1371], Laser flash-photolysis (355 nm) allows to determine relatively stable anion-radicals of misonidazole and metronidazole in aqueous solutions [1370], Solvated electrons have been formed at harder irradiation, the result of which interaction with nitroimidazole molecules is generation of their radical anions [1372], The authors [1372] have also found that fluorescence intensity of metronidazole is about 20 times more than that of misonidazole in same conditions. Photochromic properties of benzothiazole derivatives containing nitro and methyl groups in the ortho positions with respect to each other were studied by flash photolysis [1371], The application of the thermodynamic approach to predict the kinetic stability of formed nitronic acids is limited owing to specific intramolecular interactions. The lifetime of photoinduced nitronic acid anions tends to increase with rise in the chemical shift of the methyl protons. The rate constants photoinduced nitronic acids and their anions increase as the CH3C-CN02 bond becomes longer [1371],... 

Nitro-2-R-benzothiazoles DNA damage, against Staphylococcus aureus, Bacillus subtilis [362], Euglena gracilis [363], azo disperse dyes in textile [364]... 

On the other hand, oxidation of secondary 1,1-enediamines 176 with bromine results in the formation of isothioazole derivatives 179. The yields of the oxidation-cyclization reaction depend strongly on the substituent R2 (equation 71)21,143. It is noteworthy that oxidation of 177 under the same conditions does not furnish isothioazoles but, instead, benzothiazoles 180 are formed (equation 72)21. A similar product, 180, has been obtained in the case of the nitro-substituted enediamines of pyrrolidine143. The different outcomes of these reactions reveal that the reactivity of the secondary amino group of 1,1-... 

Both 5- and 6-nitro-l,3-benzothiazole (185 and 186) add methoxide at C-2 however, these adducts are unstable with respect to a subsequent ring-opening reaction.338-340 As with the benzothiazolium cation (Section V,A), the driving force for the ring-opening reaction is the generation of the... 

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