Benzothiazolone

When heated under reflux in 48% hydrobromic acid 4-bromo-2(3W)-benzothiazolones rearranged to the 6-bromo isomers (41). The mechanism is believed to involve initial protonation at C-4, followed by either bromide ion attack at C-6 (with concomitant SN2 expulsion of the 4-bromine), or bromide attack at the 4-bromo group to remove it as molecular bromine. Subsequent electrophilic bromination at the 6-position is then possible. The latter process is favored by the authors. Further bromination of 41 gave a 32% yield of the 4,6-dibromobenzothiazolone (91T2255) (Scheme 26). 

Levels of analyzed compounds were comparable with those reported in previous studies with the exception of cadmium, ammonia, 2(3H)benzothiazolone, and bisphenol A, which were higher than the published data regarding long-term composition of MSW landfill leachate from some European MSW landfills while... 

A spectrophotometric method for aldehydes in either fresh or seawater was described by Kamata [ 132], It used the colour-forming reaction between the aldehyde, 3-methyl-2-benzothiazolone hydrazone, and ferric chloride, and claimed a sensitivity of 0.01 mg/1 as formaldehyde equivalents. While Kamata clearly found evidence of the presence of aldehydes, the method appears to be not quite sensitive enough for the quantities to be found in seawater. 

The additional double bond in the corresponding allenyl 2-nitrophenyl sulphides causes a significant preference of the oxygen transfer to carbon88. The dominant ions correspond to the radical cations of 2[3//]-benzothiazolone and protonated benzothiazole, respectively88. Both ions require the transfer of two oxygens to carbon in the side-chain as well as extensive rearrangements of the molecules see Scheme 22. The transfer of... 

The presence of two carbonyl conformers has also been observed (70MI5 84MI5) in the N-acyl derivatives of benzothiazolone 112 and benzooxa-zolone 113. In benzothiazolone derivatives 112, IR stretching frequencies... 

A one-pot synthesis of benzothiazolones from 2-halonitrobenzenes has been reported (equation 23).197 The proposed mechanism involves the displacement of halide by some sulfide species (H2S or HS, n = integer) generated in situ, followed by nitro reduction and condensation with SCO. 

Ogawa and Fritz (1985) developed a method for the identification of acrolein in water. A known volume of water is passed over a column of zeolite that traps the acrolein. The column is then eluted with acetonitrile, and derivatization using DNP follows. By following this procedure, a sample that can be analyzed by HPLC is obtained. Other derivatizing agents that have been used successfully for the monitoring of acrolein in the environment include dimedon, phenylhydrazone, 4-hexylresorcinol, and 3-methyl-2-benzothiazolone (Altshuller and McPherson 1963 Peltonen et al. 1984). 

Plants. Besides 4-aminophenol, benzothiazolone and benzothiazoylacetic acid are found, both of which are formed by hydroxylation Soil. Metabolites formed are benzothiazole and benzothiazolyl-acetic acid... 

Benzoxazolones, benzothiazolones, and benzimidazolones 264 are prepared by the reaction of carbonic acid derivatives [CO(OEt)2, COCl2 or ClC02Et] with the corresponding -substituted anilines 265 (Scheme 148). 

As a result of the nitration of benzothiazolones-2 [136, 203, 204] and benzo-thiazolylthiones-2 [205, 206] with the sulfuric-nitric mixture 6-nitro isomers are obtained. 

Free formaldehyde is reacted with acetylacetone in the presence of an excess of an ammonium salt to form the yellow fluorescent compound, 3,5-diacetyl-1,4-dihydrolutidine and subsequently determined spectrophotometrically in methods A-E (14). In these methods, the test sample must be colorless and free from other carbonyl compounds. Some other derivatives have been used to analyze formaldehyde. For example, formaldehyde was reacted with sodium 4,5-dihydroxy-2,7-naphthalene disulfonate in sulfuric acid solution to yield a purple color (580 nm) and then subjected to colorimetric analysis. A purple-colored pararosaniline derivative was used to analyze formaldehyde in air (15). Air sample was passed through an aqueous solution which contained 0.4% of 3-methyl-2-benzothiazolone hydrazone hydrochloride and then a dye produced was determined at 635 or 670 nm (16). Molecular sieve (1.6 mm pettet) was used to trap formaldehyde in air samples. The formaldehyde... 

Polymers of benzoquinone, some tin-containing polymers, like poly(dialkyl tin maleate), zinc or cadmium containing polycondensates of 8-hydroxyquinoline with formaldehyde, polymers containing phosphorus, Ar,Ar -diphenylguanidine, 4-ami-no-1,2,3-triazole, benzothiazole, benzimidazole, benzothiazolone or dithiocarba-mate moieties were reported as thermostabilizers for PVC [67, 325-327]. 

C8H9CI02 5-chloro-1,3-dimethoxybenzene 7051-16-3 25.00 1.1938 2 13785 C8H9N3S 3-methyl-2-benzothiazolone hydrazone 1128-67-2 25.00 1.2407 2... 

Benzothiazolones are formed by demethylation of 2-methoxybenzothiazoles upon treatment with HBr under aqueous conditions <1998JME4915>. 6-Nitro-2-benzothiazolyl 3,6-di-0-allyl-2,4-di-0-benzyl-a-D-mannopyranoside 136 has been used as a highly efficient mannosyl donor in the presence of tetrakis(pentafluorophenyl)borate at -78 °C in DCM to give the desired /3-mannosides in high yields <2006BCJ479>. 

NTA 194 FK 1160) is a benzothiazolone derivative, a CYCLOOXYGENASE INHIBITOR with NSAID ANALGESIC. ANTIINFLAMMATORY and ANTIPYRETIC activity. 

Aldehydes, DBTScriON 3-Methyl-2-benzothiazolone hydrazone hydrochloride. 

Benzothiazolones (121) undergo Friedel-Crafts acylation through the reaction with acyl chlorides or anhydrides in the presence of a large excess (7-11 equivalents) of the AICI3-DMF reagent (Equation (21)). The same 6-acyl-2-(3//)-benzothiazolones (122) are obtained from (121) and anhydrides in the presence of polyphosphoric acid <94J0C1574>. 

A solution was prepared under argon consisting of 0.7327 g (2 mmole) of para-di-r-butyl ester of PMDA, 0.4005 g (2 mmole) ODA, and 0.56 mL triethyl amine in solution in 2 mL NMP. The solution was cooled to -10°C and 1.6976 g (4 mmole) of N,N -phenylphosphinobis[2(3H)-benzothiazolone] was added slowly. The reaction was kept at -10°C for 12 min and then allowed to return to room temperature, and stirred for 2 more hours. After diluting with 8 mL of NMP, the polymer solution was precipitated in 200 mL of methanol, filtered, washed with methanol and dried under vacuum for several days. In this way 0.83 g (79% yield) of tan polymer was isolated. 

Phenols may be converted in thiocarbamates (ArSCONRj) by a Newman rearrangement amino-thiocarbamates, are thus accessible from aminophenols. This provides a convenient route to 2-benzothiazolones. 

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