4-azidobenzoic acid

Weber and Beck-Sickinger reported a study on the photochemical behavior of different photophores [86]. For this, the synthetic pentapeptide thymopentin, or TP5 (Arg-Lys-Asp-Val-Thr) was modified with each of the photocrosslinkers (C-terminal Tyr was replaced by Phe(Tmd), and Bpa or 4-azidobenzoic acid was coupled to the N-terminus), thereby obtaining three different photoreactive peptides. The conversion and product formation were followed by LC-MS analysis after photolysis in water, n-propanol. and a water/n-propanol mixture (1 1, v/v). It was found that both the diazirine and aryl azide were quickly converted into a... 

Azidated Ch 4-azidobenzoic acid + 0-bulyryl Ch [88] and tissue formation in... 

Reduction of 9-azido-NeuAc (3) with H2/PdO in acidic aqueous methanol affords 9-amino-NeuAc quantitatively. Acylation of 9-amino-NeuAc with NHS esters of various carboxylic acids at basic conditions (pH 8-9) readily affords various 9-substituted NeuAc derivatives in the yields ranging from 45% to 25%. To the solution of 3 in aqueous methanol, PdO was added and stirred under Ha atmosphere with pH maintained at 1-2 by addition of acetic acid. The reaction mixture was filtered to remove the catalyst when it was complete as determined by TLC. To the titrate was added dioxane, and 4-azidobenzoic acid NHS ester with pH maintained between 8.0-9.0 with saturated sodium bicarbonate solution. The mixture was stirred in the dark for 48 hr. The solvent was evaporated and the residue was purified by flash chromatography to give 4 in 45% yield. Rf ... 

The photoactivated component, 2-nitro-4-azidobenzoyl hydrazide was obtained by hydrazinolysis of the V-hydroxysuccinimide ester of 2-nitro-4-azidobenzoic acid. The latter can be easily prepared, as shown in Scheme 1, from 2-nitro-4-aminobenzoic acid by the usual methods of arylazide preparation (see, e.g., Galardy et al. ). The GTP photoanalog was obtained in analogy to the synthesis of thiosemicarbazone of nucleoside 6 -monophosphates described by Dulbecco and Smith. ... 

A solution of 145 / 1 (3 mmoles) of freshly distilled hydrazine hydrate in 15 ml of dioxane is added to a solution of 915 mg (3 mmoles) of iV-hydroxysuccinimide ester of 2-nitro-4-azidobenzoic acid in 100 ml of dioxane, and the mixture is stirred for 1 hr at 0 . It is necessary to add hydrazine hydrate in the same molar quantity as the ester, since the azide group would be decomposed by an excess of hydrazine (the 2100 cm" band disappears in the infrared spectrum). The mixture is evaporated to an oil under reduced pressure, and the oil is crystallized by addition of light petroleum ether (40°-70°) and repeated evaporation. Recrystallization is from water or aqueous ethanol. Yield, 420 mg (58%) m.p., 163°-165° (decomposition) IR (KBr), cm 3300-3400 (amide), 2100 (-N3), 1530 (-NO,) UV spectrum (H,0) A, ax 250 nm ( = 21,000), Amin 227 nm (e = 11,000). The product is chromatographically and elec-trophoretically homogeneous (see the table). The compounds are detected in UV light and darken under irradiation by UV or visible light. 

A variety of acid-base complex crystals were prepared, using 2-azidobenzoic acid (2a), 3-azidobenzoic acid (3a), and 4-azidobenzoic acid (4a) as acids and dibenzylamine (db), A-benzyl-2-phenylethylamine (bp), and dicyclohexylamine (dc) as bases, which are shown in Scheme 8.7 [48]. Among nine combinations of acid-base complexes, suitable crystals for X-ray work were obtained for the six complexes of 2a-db, 3a-db, 3a-dc, 4a-bp, 4a-db, and 4a-dc. For the other three complexes of 2a-dc, 2a-bp, and 3a-bp, snitable crystals were not obtained. For the complexes of 3a-db and 4a-db, two crystal forms, I and II, were obtained. The crystal structures for the eight kinds of crystals before the photo-irradiation were analyzed by X-rays. Then each crystal was irradiated with a high-pressure Hg lamp with a filter to select the wavelength longer than 420 nm or 390 nm at ca. 80 K for 2-32 h. The intensity data were collected at ca. 80 K and the structnres were analyzed. For the three crystals, 4a-db-I, 4a-db-II, and 4a-dc, it was impossible to analyze the structures after photo-irradiation, because of poor intensity data. 

The action of nitrous acid on o-aminohydroxamie acids gave products that are believed to be triazine hydroxamic acids, e.g., 28. These gave a red color with ferric chloride, and 28 was converted by sodium hydroxide into o-azidobenzoic acid (29). 

Alkoxy-3//-azepines 87 by Photolysis of Esters and Amides of 2-Azidobenzoic Acid in Alcohol/THF Solution General Procedure 74... 

Two structurally related arylazides were also transformed similarly. Porter et al. described <1997S773> that ketone 486 can conveniently be transformed into 487 when treated with a substituted acetonitrile containing an active methylene group under basic conditions. The products were obtained in most cases in excellent yields. Cyclization to 489 proceeds in a similar manner as described by an Italian team <1996FA131, 2000EJM333> the n-azidobenzoic acid 488 yielded the fused [l,2,3]triazole 489. 

Azidobenzoic Acid. See under Benzoic Acid and Beil 9, 418, (168-9) [286]... 

Azidobenzoic Acid Amide. See under Benzoic Acid Amide and Beil 9, 418 Azidobenzoic Acid Hydrazonium Hydroxide. See under Benzoic Acid Hydrazonium Hydroxide and Beil 16, 548 Azidobenzoic Acid, Methyl Ester. See under Benzoic Acid and Beil 9, 418 Azidobenzonitrile. See under Benzonitrile and Beil 9, 418-9 (169)... 

Base-catalyzed condensation of 2-azidobenzoic acid or its nitrile with active methylene compounds furnished the 4-substituted 1,2,3-triazolo [l,5-a]quinazolines (290) in good yield [66JCS(C)2290 69JCS(D)423 74JCS(P1)534]. 

Azides, organic (list) (cont d) azidobenzenedioxime 1 A630 azidobenzoic acid hydrazoruuni hydroxide 1 A630... 

Azido and Azides of Benzoic Acid and Derivatives Azidobenzoic Acid (called Azido- or Triazo-benz-oesaure in Ger), N3.CgH4CC>2H mw 163.12, N 25-76%. The 2-Azido, ndis(from w), mp I46°(dec) 3-Azido, Ifts, mp 159-160° and the 4-Azido deriv, lfts, mp 145°(dec)(Ref 2) are described in the iit-erature(Ref 1)... 

Benzoic Acid Hydrazonium Hydroxide. Incorrectly listed in Vol l,p 630-L for 3rd item from bottom which should read Azidobenzoic Acid Diazonium Hydroxide... 

Phenyl azide itself absorbs at 250 nm (e 10,000) with the characteristic shoulders of an aryl azide at 277 and 286 nm. Electron withdrawing substituents produce a shift of the X,max towards the visible, e.g. esters of p-azidobenzoic acid absorb at 280 nm (e 20,000). Nitro substitution leads to the appearance of an absorption band at still longer wavelengths, e.g. 2-nitro-4-azidophenylalanine (X.max 333 nm e 1,700). Further examples are given in Patai (1971). 

Purvis, R., Smalley, R.K., Strachan, W.A. and Suschitzky, H. (1978) The photolysis of o-azidobenzoic acid derivatives a practicable synthesis of 2-alkoxy-3-alkoxycarbonyl-3H-azepines. Journal of the Chemical Society, Perkin Transactions 1, (3), 191-195. 

A representative of this ring system (namely, 5-oxo-3-phenyl-4,5-dihydro[l,2,3]triazolo[l,5-a jquinazoline (335)) has been prepared by the reaction between o-azidobenzoic acid and phenylacetonitrile in the presence of sodium methoxide (66JCS(C)2290). This is illustrated in Scheme 57. 

Similarly, treatment of the anthranilic acid derivative (248) with nitrous acid gave the cyclic product 249 which underwent hydrolysis in aqueous alkali to afford o-azidobenzoic acid 1,2-Diacetylhydra-... 

In the aromatic series it has also been shown that the electron-withdrawing effect of the azido substituent is similar to those of the bromo and iodo groups. Smith, Hall and Kan have recorded the ionization constants of the ortho-, meta- and />ara-azidobenzoic acids and azidoanilines (Table 3) and from the Hammett-Burkhardt relationship these authors derived values for the constant of the azido... 

Table 3. Ionization constants of azidobenzoic acids and azidoanilines ...

Thermolysis of bis (o-azidobenzoyl) peroxide (233) at 80° in benzene in the absence of air led to a number of products in which the azido group was left intact o-azidobenzoic acid (234) (102%), o-azido-biphenyl (235) (18%), phenyl o-azidobenzoate (236) (20%), and a mixture of unidentified, apparently aliphatic, esters of o-azidobenzoic... 

TSUNODA YAMAOKA Amino-azidobenzoic Acid Derivatives... 

Dichloronaphthol(mp. 107b), 4-niethoxynaphthol (mp,125 C), l-phenyl-3-methylpyrazolone(mp.129 C) and 2,5-dichloroacetacetanilide(mp.95 C) were used as coupler to photodecomposed 2-monosubstitutedamino -5-azidobenzoic acids. 

Figure 1. Spectral sensitivities of 2-monosubstituted-amino-5-azidobenzoic acids...

In this photocolor reaction of 2-monosubstituted-amino-5-azidobenzoic acid, the imino and carboxilic groups in the molecules are very important. The compounds (IV and V) which hydrogen of these groups are substituted with alkyl group are very hypsochromic when they are photodecomposed. The reason why the photodecomposed IV and V are hypsochromic may be due to the fact that they can not have inner salt structure like VI. ... 

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