D diazotization

Figure 4. Modifications of phenolic groups (a) N-acetylimidazole (b) iodination (c) TNM (d) diazotization.

Sol 7. (d) Diazotization of anthranilic acid gives a diazonium salt, which on treatment with a mild base undergoes elimination of CO2 and N2 to give benzyne intermediate (I). It immediately undergoes Diels—Alder reaction to... 

To a cold mixture of 800 cc. of 95 per cent ethyl alcohol and 200 cc. of concentrated sulfuric acid (Note i) in a 5-I. round-bottom flask, provided with an efficient mechanical stirrer, is added 250 g. (1.33 moles) of crude 3-bromo-4-aminotoluene (p. 8). The solution is stirred and cooled to 10° and a solution of 148 g. (2.05 moles) of d.s.p. sodium nitrite in 260 cc. of water is added from a separatory funnel. During this addition, the temperature of the mixture must not be allowed to rise above 10°. After all of the nitrite solution has been added, the mixture is stirred twenty minutes longer to complete the diazotization. 

The o-aminophenylpropiolic acid 4 (20 g) in water (60 mL) and aqueous ammonia (9 mL, d = 0.88) was added with shaking during 15 minutes to a mixture prepared from ferrous sulfate (220 g), water (440 mL), and aqueous ammonia (110 mL, d = 0.88). After 45 minutes, with occasional shaking but no external cooling, the suspension was filtered. The residue was washed with water, and the combined filtrates were treated with ammonium acetate (60 g) and made weakly acidic with acetic acid. The solution was then cooled to 0°C by addition of crushed ice, and then made acidic to Congo-red with concentrated hydrochloric acid (70-80 mL). Additional hydrochloric acid (20 mL, 2 N) was immediately added, and the turbid solution which resulted was diazotized with 20% aqueous sodium nitrite, after which the mixture was kept at 70°C. The cinnoline acid 6 was separated over 45 minutes as a dark brown, granular solid (12.5 g), m.p. 260-265°C. ... 

Ureido and benzamido derivatives have been prepared, and a 6-amino group in a pyrido[3,2-d]pyrimidine can be diazotized and reduced. ... 

Diazotization of biphenyl-2,2 -diamine, followed by treatment with aqueous ammonia, gives the parent compound la.331 A number of analogs lb-d, prepared in the same way. are all unstable oils.331... 

OB to C02 -54,3%, mp explds at approx 1S4°, hygr crysts. Prepd by dissolving m-nitroaniline in an excess of dil perchloric acid (d 1.12g/cc), the excess being such that, at the end of the reaction, free acid is present. A sufficient quantity nf Na nitrite in solid form or in a sstd soLp. is added to effect diazotization. The mixt is cooled during the Na nitrite addition ,... 

Metafor 3- Mononitrophenol Monoclinic prisms from eth or dil HC1 mp 97° bp 194° at 70mm, decomps when distd at ordinary pressure d 1.485g/cc at 20°, 1.2797 at 100°. Does not volatilize with steam cannot be prepd by the nitration of phenol. Can be obtained by boiling diazotized m-nitroaniline with w and sulfuric acid (Ref 3). SI sol in w, sol in ale. Highly toxic by ingestion and inhalation Refs 1) Beil 6, 222-24, (116), [212-14]... 

For quantitative work, it is necessary to estimate the concentration of 5-amino-l-(P-D-ribofuranosyl)imidazole in aqueous solution. It seems that the only available method is the Bratton-Marshall assay, which was originally developed for the estimation of arylamines in biological fluids. The principle of the method is the spectrometric estimation of a salmon-pink colored dyestuff obtained by diazotation in situ, followed by coupling with /V-( 1 -naphthyl)ethyl-enediamine.65 The only remaining problem then is to know the molar extinction of this dye because pure samples of AIRs are not available. A value of 16800 at 520 nM was obtained for the dyes prepared from a model compound, 5-amino-l-cyclohexylimidazole-4-carboxylic acid (54), which is crystalline. A comparable molar extinction can be expected for the dye prepared from imidazole 55, if the carboxyl group does not exert too much influence on the chromophore. Actually, its influence is perceptible even with the naked eye, the dyestuff prepared from 53 having a somewhat different, wine-red color, with max>520 nM. The molar extinction for 55 is 17400 at 500 nM. When the decarboxylation of 54 was conducted under mild acidic conditions (pH 4.8, 50°C, 1 hour), estimation of 5-aminoimidazole 55 by the Bratton-Marshall method led to the conclusion that the reaction was almost quantitative.66 Similar conditions for the final decarboxylation were adopted in the preparation of samples of AIRs labeled with stable isotopes.58... 

Zopf, D.A., Tsai, C.-M., and Ginsburg, V. (1978b) Carbohydrate antigens coupling of oligosaccharide-phenethylamine derivatives to edestin by diazotization and characterization of antibody specificity by radioimmunoassay. In Methods in Enzymology, (V. Ginsburg, ed.), Vol. 50, pp. 163-169. Academic Press, New York. 

Kirk Othmer II (1966), 864 l-Azido-2-iodobenzene, C6H4N3I mw 245.03, N 17.15% strong smelling oil, bp 90-91° at 0.9 mm Hg, d 1.8893 at 25°, refractive index 1.6631 at 25° prepd by diazotizing aniline with NaN3. No expl props are reported. The l-Azido-3-iodo- and 1-Azido-4-iodo-derivs are also known (Ref 2)... 

The needle-like shape of the crystals prevents their being easily poured (into the capsule) making them liable to felt so the aim is to produce short crystals either by a suitable selection of conditions for the reactions of diazotization and precipitation of the product (D. Smolenski and Plucinski [13]) or by the addition of certain substances to the solution from which the product is to be precipitated Garfield [14], for instance, suggests for this purpose the addition of triphenylmethane dyestuffs to the solution. 

There is considerable interest in the chemistry of triazines as some of these compounds show pronounced antimalarial, antimicrobial and antiviral activity (76JCS(Pl)252l). Therefore two types of thiophenes annelated with a triazine ring will be mentioned. Thieno[2,3-d]-1,2,3-triazines were synthesized by cyclization of diazotized 2-aminothiophene-3-carboxamides (equation 55) (73M1586). Treatment of 3-alkylthio-6-styryl-5-oxo-2,5-dihydro-l,2,4-triazines with phosphorus pentasulfide in pyridine yields thieno[2,3-e]-l,2,4-triazines (equation 56) (78CI(L)585). Probably a thiation with subsequent cycloaddition and elimination of a hydride ion is involved. 

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