Reaction of N-Alkyl-6(4)-bromo-2,1,3-benzoxadiazol-4(6)-amines with terminal alkynes

N-Alkyl-6(4)-bromo-2,1,3-benzoxadiazol-4(6)-amines reacted with terminal alkynes to give aminosubstituted 2,1,3-benzoxadiazoles containing acetylenic fragments directly attached to the carbocycle.     

Synthesis of 4(6)-aryloxy- and 4-arylthio-2,1,3-benzoxadiazoles

Reactions of 4,6-dibromo-2,1,3-benzoxadiazole with phenols or arenelthiols lead to 4-aryloxy-6-bromo-2,1,3-benzoxadiazoles or 4-arylthio-6-bromo-2,1,3-benzoxadiazoles, respectively. Isomeric 6-aryloxy-4-bromo-2,1,3-benzoxadiazoles were synthesized by replacement of the fluorine atom in 2,6-dibromo-4-fluoro-1-nitrosobenzene with phenols and treatment of the resulting 4-aryloxy-2,6-dibromo-1-nitrosobenzene with sodium azide.     

Synthesis and reduction of some 1H-2,1,3-benzothiadiazin-4(3H) one 2,2-dioxides

Several 2,1,3-benzothiadiazin-4(3H) one 2,2-dioxides were synthesized as possible sweetening agents by reacting sulfamoyl chloride with various anthranilic acid derivatives. The isolation of 1-methyl-4-methoxy-2,1,3-benzothiadiazine 2,2-dioxide and preparation of 3,4-dihydro-2,1,3-benzothiadiazine 2,2-dioxide is also reported.     

Researches on 2,1,3-thia- and selenadiazole XLV. Nitration of 4-hydroxy- and 4-ethoxybenzo-2,1,3-thiadiazoIe

Nitration of 4-hydroxybenzo-2,1,3-thiadiazole under conditions generally used for phenols, gave a high yield of 4-hydroxy-5-nitrobenzo-2,1,3-thiadiazole. The latter is readily reduced to 4-hydroxy-S-aminobenzo-2,1,3-thiadiazole which on treatment with orthoformic ester gives oxazolo [5,4-e]benzo-2,1,3-thiadiazole. 4-Ethoxybenzo-2,1,3-thiadiazole is nitrated under similar conditions, giving a high yield of a mixture of equal quantities of 4-ethoxy-S-nitro- and 4-ethoxy-7-nitrobenzo-2,1,3-thiadiazole.     

Syntheses and characterizations of 4-(3,17beta-dihydroxyestra-1,3,5(10)-trien-6alpha- and 6beta-yl)amino-7-nitro-2,1,3-benzoxadiazoles as fluorescent probes.

4-(3,17Beta-dihydroxyestra-1,3,5(10)-trien-6alpha- and 6beta-yl)amino-7-nitro-2,1,3-benzoxadiazoles have been synthesized and characterized as fluorescent probes for use in a receptor assay and/or a homogeneous immunoassay for estradiol. The fluorescence intensities are strongly dependent upon the solvent polarity used. The intensities in water were reduced to less than 1% of those in ethyl acetate, and a blue shift was also observed in polar solvents. The quenched fluorescence in aqueous solution was recovered by adding bovine serum albumin or an anti-estradiol antibody. Adding intact estradiol inhibited the fluorescence recovered by the antibody.     

Researches on 2,1,3-thia- and selenadiazole XLV. Nitration of 4-hydroxy- and 4-ethoxybenzo-2,1,3-thiadiazoIe

Nitration of 4-hydroxybenzo-2,1,3-thiadiazole under conditions generally used for phenols, gave a high yield of 4-hydroxy-5-nitrobenzo-2,1,3-thiadiazole. The latter is readily reduced to 4-hydroxy-S-aminobenzo-2,1,3-thiadiazole which on treatment with orthoformic ester gives oxazolo [5,4-e]benzo-2,1,3-thiadiazole. 4-Ethoxybenzo-2,1,3-thiadiazole is nitrated under similar conditions, giving a high yield of a mixture of equal quantities of 4-ethoxy-S-nitro- and 4-ethoxy-7-nitrobenzo-2,1,3-thiadiazole.For Part XLIV see [1].     

Development of hydrophilic fluorogenic derivatization reagents for thiols: 4-(N-acetylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole and 4-(N-trichloroacetylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole

Sensitive, reactive, and hydrophilic fluorogenic reagents for thiols with the benzofurazan skeleton, 4-(N-acetylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (AcABD-F) and 4-(N-trichloroacetylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (TCAcABD-F) have been developed. These reagents reacted with thiols within 10 min at 60 degrees C. AcABD-F and TCAcABD-F themselves do not fluoresce but are strongly fluorescent after the reaction with thiol compounds. The generated derivatives were highly water-soluble, since they dissociated a proton and ionized in the neutral pH region. The derivatives with four biologically important thiol compounds were separated on a reversed-phase HPLC column and detected fluorometrically at 504 nm with excitation at 388 nm. The detection limit attained for homocysteine with AcABD-F was 25 fmol on column (11 nM) (signal-to-noise ratio = 3), and that for glutathione with TCAcABD-F was 45 fmol on column (20 nM).     

Reactivity of 4-nitro- and 4-nitro-7-halogeno-2,1,3-benzothiadiazoles toward methoxide ion

4-Nitro-2,1,3-benzothiadiazole reacted with sodium methoxide (0.1-1 M) in methanol yielding 2,1,3-benzothiadiazole-4, 7-dione monoxime (syn+anti). Methoxy-dehalogenation of 4-nitro-7-halogeno-derivatives yielded 4-nitro-7-methoxy-2,1,3-benzothadiazole under similar conditions. In both eases transitions attributable to the formation of Meisenheimer complexes were detected.     

Samarium,Europium, and Gadolinium Complexes with 4-(2,1,3-Benzothiadiazol-4-ylamino)pent-3-en-2-onate

Russian Journal of Coordination Chemistry - New lanthanide complexes with 4-(2,1,3-benzothiadiazol-4-ylamino)pent-3-en-2-onate (L–) [Ln(L)3] are synthesized using two methods: by the reaction...     

Palladium(II)-catalyzed arylation of unactivated C(sp3)-H bonds by using 2,1,3-benzoselenadiazole-4-amine as directing ligand

A modified bidentate directing ligand derived from 2,1,3-benzoselenadiazole (BSeD) was designed and synthesized. It exhibited high regioselectivity in the catalytic activation of unactivated C(sp³)-H bonds with aryl iodides in the presence of palladium catalyst in yields up to 94%.     

Reductive sulfur extrusion reaction of 2,1,3-benzothiadiazole compounds: a new methodology using NaBH4/CoCl2·6H2O(cat) as the reducing system

A new simple and efficient methodology for reductive sulfur extrusion from 2,1,3-benzothiadiazole compounds has been developed using NaBH₄ in the presence of catalytic amounts of CoCl₂·6H₂O (1 mol %). This method is an efficient alternative for the generation of various 1,4-disubstituted-2,3-diaminobenzene derivatives from 4,7-disubstituted-2,1,3-benzothiadiazoles. The diamines can be easily converted into 4,7-disubstituted-quinoxaline compounds by simple reaction with glyoxal-sodium bisulfite.     

Synthesis and crystal structure of a luminescent metal-organic framework based on 4,7-(4-carboxyphenyl)-2,1,3-benzoxadiazole

Russian Chemical Bulletin - A three-dimensional coordination polymer was synthesized by the reaction of zinc(ii) nitrate with 4,7-(4-carboxyphenyl)-2,1,3-benzoxadiazole and...     

HETEROCYCLIC SYSTEMS CONTAINING BRIDGE HEAD NITROGEN ATOM: REACTION OF 5-MERCAPTO-4H-IMIDAZO[4,5-e]- [2,1,3]BENZOTHIADIAZOLES AND 5,6-DIAMINO[2,1,3]BENZOTHIAZOLE WITH 3-(2-BROMOACETYL)COUMARINS

Condensation of 5-mercapto-4H-imidazo[4,5-e][2,1,3]benzothiadiazole (I) with various 3-(2-bromoacetyl)coumarins, followed by PPA cyclization of the intermediate ketones II, yielded 3-(2,8-dithia 1,3,5b, 9-tetraaza cyclopenta(b)-as-indacen-6-yl)chromen-2-ones III. Reaction of 5,6-diamino[2,1,3]benzothiadiazole with 3-(2-bromoacetyl)- coumarin in anhydrous ethanol containing fused sodium acetate gave the corresponding 2-coumarinyl 3,4-dihydro-1,4-pyrazino[5,6-e][2,1,3]benzothiadiazoles IV.     

Synthesis and application of 4-(N,N-dimethylaminosulfonyl)-7-N-methylhydrazino-2,1,3-benzoxadiazole (MDBDH) as a new derivatizing agent for aldehydes

In a five step synthesis, 4-(N,N-dimethylaminosulfonyl)-7-N-methylhydrazino-2,1,3-benzoxadiazole (MDBDH) was prepared in high yields as a stable new derivatizing agent for carbonyl compounds. Reagent and derivatives have not been described in literature before. Major advantage of this substance compared with similar reagents is its improved solubility in polar solvents, e.g. methanol and ethanol. MDBDH reacts with aldehydes in the presence of an acidic catalyst under formation of the corresponding hydrazones. These are separated by means of reversed-phase liquid chromatography and detected UV/vis spectroscopically at wavelengths around 450 nm, depending on the individual hydrazone. MDBDH reacts with oxidizers as nitrogen dioxide and nitrite to only one product, 4-(N,N-dimethylaminosulfonyl)-7-methylamino-2,1,3-benzoxadiazole (MDBDA), which can easily be separated from the hydrazones of lower aldehydes. Due to large molar absorptivities and absorption maxima at wavelengths > 430 nm, limits of detection range from 4 x 10(-8) to 6 x 10(-8) mol.L-1, and limits of quantification range from 1 x 10(-7) to 2 x 10(-7) mol.L-1 for the individual hydrazones. The method was applied to the determination of aldehydes in automobile exhaust.     

Fluorogenic reagent for thiols: 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole

4-(N,N-Dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) was synthesised for use as a more reactive, thiol-specific fluorogenic reagent than 4-(aminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F). The former had negligible fluorescence whereas its thiol derivatives fluoresced intensely at about 510 nm (excitation occurred at about 380 nm). The DBD-F reacted quantitatively with thiols after 10 min at 50 degrees C and pH 8.0 and the reaction rates were several times higher than those with ABD-F; it is suggested that the electron withdrawing effect of the dimethylsulphonamide group (SO2NMe2) is larger than that of the sulphonamide group (SO2NH2). No reaction occurred with alanine, proline, cystine or cysteic acid under the same conditions. The fluorescence intensities of the derivatives were found to be higher in neutral and acidic media than in alkaline solutions. The thiol derivatives of DBD-F were separated by high-performance liquid chromatography and detected fluorimetrically, the detection limits being 0.92, 0.16, 0.13, 0.16 and 0.32 pmol for cysteine, glutathione, homocysteine, N-acetylcysteine and alpha-mercaptopropionylglycine, respectively. The method was applied to the determination of thiols in rat tissues.     

Semmler-Wolff aromatization of 4-hydroxyimino-4,5,6,7-tetrahydro-[2,1,3]benzoxadiazole and 4-hydroxyimino-4,5,6,7-tetrahydro[2,1,3]benzoxadiazole 1-oxide and some properties of the obtained amines

The Semmler-Wolff aromatization of 4-hydroxyimino-4,5,6,7-tetrahydro[2,1,3]benzoxadiazole and its 1-oxide derivative in sulfuric acid and in acetic anhydride gave 4-amino[2,1,3]benzoxadiazole and 4-acetamido[2,1,3]benzoxadiazole 1-oxide. Some reactions of the resultant amines were studied.     

聚苯撑乙炔-苯并噻二唑共聚物的合成及光谱性能

利用钯催化剂[Pd(PPh₃)₂Cl₂]和相转移催化剂(PTC), 采用Heck交叉偶联缩聚反应合成了聚(苯撑乙炔撑-苯并噻二唑)系列交替共聚物(PPE-BT), 比较了聚合物的紫外吸收光谱和荧光光谱特征.     

Superelectrophilic heterocycles: facile S(N)Ar-S(E)Ar couplings involving very weak carbon nucleophiles

Superelectrophilic halonitro-2,1,3-benzoxadiazoles undergo remarkably facile carbon-carbon couplings with some electron-rich aromatics and heteroaromatics, affording quantitatively products exhibiting an intense visible absorption due to strong intramolecular charge transfer.     

Über die Umsetzung von 6-Chlor-4-phenyl-3,4-dihydro-1H-2,1,3-benzothiadiazin-2,2-dioxid mit 1,4-Dijodbutan

Zusammenfassung Bei der Umsetzung des Dinatriumsalzes von 6-Chlor-4-phenyl-3,4-dihydro-1H-2,1,3-benzothiadiazin-2,2-dioxid (1) mit 1,4-Dijodbutan inDMF wurde das erwartete 1,3-Butano-derivat nich erhalten.1 wurde einerseits zu 6-Chlor-4-phenyl-1H-2,1,3-benzothiadiazin-2,2-dioxid (4) dehydriert, andrerseits traten je nach Herstellungsweise des Dinatriumsalzes Methylierungsreaktionen ein bzw. es entstanden 6-Chlor-1-(4-jodbutyl)-4-phenyl-3,4-dihydro-1H-2,1,3-benzothiadiazin-2,2-dioxid (7) und 6,6-Dichlor-4,4-diphenyl-3,3,4,4-tetrahydro-3,3-tetramethylenbis(1H-2,1,3-benzothiadiazin)-2,2,2,2-tetroxid (8).

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Reaction of 6-chloro-4-phenyl-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide with 1,4-Diiodobutane. (Cyclic and bicyclic sulfamides III)

On reaction of the disodium salt of 6-chloro-4-phenyl-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide (1) with 1,4-diiodobutane inDMF the expected 1,3-butano derivative was not obtained. On the one hand1 was dehydrogenated to give 6-chloro-4-phenyl-1H-2,1,3-benzothiadiazine-2,2-dioxide (4), on the other hand according to the method of preparation of the disodium salt either methylation reactions occured or 6-chloro-1-(4-iodobutyl)-4-phenyl-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide (7) and 6,6-dichloro-4,4-diphenyl-3,3,4,4-tetrahydro-3,3-tetramethylenebis(1H-2,1,3-benzothiadiazine)-2,2,2,2-tetroxide (8) were formed.

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Herrn Prof. Dr.H. Nowotny gewidmet.     

Use of 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole as a labelling reagent for peroxyoxalate chemiluminescence detection and its application to the determination of the beta-blocker metoprolol in serum by high-performance liquid chromatography.

Fluorogenic reagents having a benzofurazan moiety, viz., 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F), 7-fluoro-4-nitro-2,1,3-benzoxadiazole and 4-(aminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole, were compared for the sensitive analysis of their derivatives by high-performance liquid chromatography with peroxyoxalate chemiluminescence detection. Of the proline derivatives, DBD-proline was the most sensitive with a detection limit of 2 fmol. The optimum concentrations of bis[4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl] oxalate and H2O2 for the post-column reaction were 0.5 and 75 mmol dm-3 respectively and amino acids and beta-blockers derivatized with DBD-F were detected in the range 0.2-40 fmol (signal-to-noise ratio = 3) using the proposed method. The lower detection limit of metoprolol (a beta-blocker having an isopropylamino group) spiked in serum was 0.8 ng ml-1 using 20 microl of serum (signal-to-noise ratio = 5).