Azobenzene chloride

Threading of two cyclodextrins onto a symmetrical dumbbell can occur head-to-head, head-to-tail, or tail-to-tail, defining a new class of diastereoisomeric [3]-rotaxanes, as shown schematically in Figure 2.12d. Anderson and co-workers have shown that end-capping of 4,4,-bis(diazonio)azobenzene chloride 43 with 2,6-dimethylphenol 44 in the presence of a-CDX produced the [3]-rotaxane 45 in 12% yield, in addition to the [2]-rotaxane 46 in 9% yield, and free dumbbell 47 in trace amounts (Figure 2.18).42 The stereochemistry of the [3]-rotaxane species is remarkable because the two cyclodextrin beads have their smallest rims facing to each other. Therefore the threading reaction was stereoselective. The reasons for the exclusive formation of the tail-to-tail stereoisomer are not clearly established. 

R. Yuan, Y.Q. Chai, and R.Q. Yu, Poly(vinyl chloride) matrix membrane pH electrode based on 4,4 -bis[(N,N-diakylamino)-methyl]azobenzene with a wide linear pH response range. Analyst 117, 1891-1893 (1991). 

Lund and coworkers [131] pioneered the use of aromatic anion radicals as mediators in a study of the catalytic reduction of bromobenzene by the electrogenerated anion radical of chrysene. Other early investigations involved the catalytic reduction of 1-bromo- and 1-chlorobutane by the anion radicals of trans-stilhene and anthracene [132], of 1-chlorohexane and 6-chloro-l-hexene by the naphthalene anion radical [133], and of 1-chlorooctane by the phenanthrene anion radical [134]. Simonet and coworkers [135] pointed out that a catalytically formed alkyl radical can react with an aromatic anion radical to form an alkylated aromatic hydrocarbon. Additional, comparatively recent work has centered on electron transfer between aromatic anion radicals and l,2-dichloro-l,2-diphenylethane [136], on reductive coupling of tert-butyl bromide with azobenzene, quinoxaline, and anthracene [137], and on the reactions of aromatic anion radicals with substituted benzyl chlorides [138], with... 

Figure 13-35 illustrates the mechanism for the formation of p-hydroxyazoben-zene beginning with the reaction of benzenediazonium chloride with an aromatic system activated by an -OH. The mechanism for the reaction with an amine is similar. Figure 13-36 illustrates the reaction of a diazonium salt with an amine. The product of the reaction in Figure 13-36 is p-(dimethylamino) azobenzene. 

Aminophenylazobenzene, 3487 Azobenzene (Diphenyldiazene), 3483 2,2 -Azobis(2-amidiniopropane) chloride, 3089 2,2 -Azobis(2-amidiniopropane) peroxodisulfate, 3091 2,2 -Azobis(2,4-dimethylvaleronitrile), 3668 Azo-A-chloroformamidine, 0792 2,2 -Azo-3,5-dinitropyridine, 3238 Azoformaldoxime, 0815 Azoformamide, 0816 Azoisobutyronitrile, 3011 2,2 -Azoisovaleronitrile, 3345 Azomethane, 0910 Azo-A-methylformamide, 1601 Azo-A-nitroformamidine, 0825 3,3 -Azo-(l-nitro-l,2,4-triazole), 1401... 

Azobenzene reacts with mercury(II) chloride to give (120a) which undergoes transmetallation with TeCb to give (120b). Partial reduction of (120b) with hydrazine affords l-chloro-lA , 2,3-... 

C)C12] complexes [302], which has been used with azobenzene, N,N -dimethylben-zylamine, and so on. Sequential arylations enable the synthesis of complexes with two different ligands of the type [Au(C,N)ArCl], Upon treatment with phosphine or chloride, some of the N,C quelated diarylgold(III) chloride complexes undergo reductive elimination of the aryl ligands to give biaryls [303]. Figure 1.60 presents some examples of these complexes. 

Azobenzene is oxidatively cyclized to benzo(c)cinnoline (CIX) when exposed to sunlight in strongly acidic solutions,172 or in an acetic acid and ferric chloride mixture.124 As irradiation of azobenzene in neutral solutions is known to result in cis-trans equilibration, it seems that the... 

It can be prepd by treating azobenzene-4-diazonium chloride with K dichromate (Refs... 

The incorporation of a cationic azobenzene derivative, p-( a> -dimethyl-ethanolammonioethoxyj-azobenzene bromide, into nanoporous silica films and the photochemical reactions of the adsorbed dye were investigated. The nanoporous silica films were prepared from tetramethoxysilane and octadecyltrimethyl-ammonium chloride by the rapid solvent evaporation method which we have reported previously. The adsorption of the cationic azo dye was conducted by casting an ethanol solution of the dye onto the nanoporous silica films. Upon UV light irradiation, trans-azobenzene isomerized photochemically to the c/s-form and photochemically formed c/ s-form turned back to the frans-form upon visible light irradiation. The nanoporous silica films were proved to be an excellent reaction media to immobilize organic photocromic species. 

Aniline may be made (I) hy Ihe reduction, with iron or tin in HOI, of nitrobenzene, and (2) by the amination of chlorobenzene by healing with ammonia to a high temperature corresponding to a pressure of over 200 atmospheres in the presence of a catalyst (a mixture of cuprous chloride and oxide). Aniline is the end-point of reduction of most mono-nitrogen substituted benzene nuclei, as nitrosobenzene, beta-phenylhydroxylamine. azoxybenzene, azobenzene, hydrazobenzene. Aniline is detected by the violet coloration produced by a small amount of sodium hypochlorite. 

Benzenediazonium Sulfocyanate(Di azobenzene Sulfocyanate or Diazobenzene Thiocyanate), C6Hs.N2.SCN mw 163.19, N 25.75% yel solid, mp- expl on heating or impact. Can be prepd by mixing.an ice cold soln of benzenediazonium chloride in abs ale with the ealed amt of K sul-focyante. This is a very powerful, sensitive and unstable expl... 

It has been known for some time that irradiation of azobenzene (324) in either 22 N sulfuric acid350 351 or acetic acid with added ferric chloride 352 yields benzo[c]cinnoline (325). This is accompanied by the formation of an almost equal quantity of benzidine (326), undoubtedly arising by rearrangement of hydrazobenzene (327). The mechanism of this reaction differs, therefore, from that of the stilbene cyclodehydrogenation, and azobenzene itself functions as the hydrogen acceptor. Yields of not more than 50% of benzo[c]cinnoline are generally observed. 

The photolysis of the meso-ionic 1,4-diphenyl-1,2,4-triazol-3-one (200, R1 = R3 = Ph, R2 = H) was stated97 to yield phenyl isocyanate (13%), iV.N -diphenylurea (23%), and the bicyclic compound 215 (49%). These results were interpreted in terms of the fragmentation of the photo-intermediate 213 yielding the JV-phenyldiazirine (214).97 A later publication by the same group97b reports different results. Photolysis of meso-ionic 1,4-diphenyl-1,2,4-triazol-3-one (200, R1 = R3 = Ph, R2 = H) was stated to yield97 phenylisocyanate and the bicyclic compound 215. Later studies,7b have shown that the bicyclic compound 215 is not produced by the photolysis of 200, R1 = R3 = Ph, R2 = H. Irradiation in methanol-methylene chloride gave methyl phenylcar-bamate (25%), benzimidazole (18%), and azobenzene (7%). 

Diazocine 8 was found to form complexes very slowly or not at all with palladium chloride or silver nitrate. ( )-Azobenzene behaved similarly, and since both compounds have similar pXa values, the ease of complex... 

Dinitro-2,2 -di methyl azobenzene red-bm lfts (from toluene), mp 258° readily sol in boiling glacial acetic acid or nitrobenzene and in benz, diffc sol in ale prepd by treating 5-nitro-l-methylbenzene-2-diazonium sulfate with a cuprous chloride soln in HC1 (Ref 1)... 

The formation of highly UV-absorbing derivatives of estrogens with azobenzene-4-sulfonyl chloride [29] has been examined for analysis in biological extracts. The derivatives are separated by TLC arid are quantitated by direct densitometry of the chromatoplates. 

Azidobenzaldehyde, 2693 f Aziridine, 0859 Azobenzene, 3477 Azoformamide, 0812 Azoxybenzene, 3479 Benz aldehyde oxime, 2756 Benzyl chloride, 2734 4-Bromoaniline, 2289... 

Poly(L-lysine) containing azobenzene units linked to the side chains by means of a sulfonamide function (Scheme 4, Structure VI), was obtained by treating poly(L-lysine) with p-phenylazobenzenesulfonyl chloride. The poly(a-amino acid) was modified quantitatively conversion to the azo-lysine units of VI was effectively 100%. The azo-modified polypeptide was soluble in HFP, in which it exhibited an intense photochromism attributed to the trans-cis photoisomerization of the azobenzene units. Like other sulfonated azobenzene compounds, 33 azosulfonyl-modified polymers of L-lysine were found to be very stable in their tis form, and no thermal decay was observed at room temperature over periods of times as long as several weeks. Interconversion between the two forms at room temperature could only be effected by irradiation at appropriate wavelengths. This behavior allowed the authors to purify the trans and cis forms of the model compound NE-azobenzenesulfonyl-L-lysine (VII) by chromatography, and to measure the absorption spectra of the two pure photoisomers. 

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