2- 1-phenylazo

DImethoxyphosphoryl-2-(4-phenylazo-plienylazo)-beriisteiiisai]re-dimethylester1 Eine Losung von... 

The reaction of amines with the 4-phenylazo derivative (228) results in their rearrangement into triazolines. Depending on the basicity of the amines and the size of the alkoxy group, three different triazolines (229. 230, and 231) are obtained (Scheme 117) (454. 459, 472). In all cases, the first step involves nucleophilic addition of the amine to the carbonyl group followed by ring opening and further ring closure. 

Coupling of 2-diethyiamino-4-methvlselenazole with phenyldiazonium chlonde gives the corresponding 5-phenylazo compound [orange granules, m.p. 101°C (26)]. 

Bulka et al. (43) have demonstrated the electrophilic reactivity of selenazoles possessing an hydrazonc in the 2-position and nonsubstituted in the 5-position toward diazonium salt to give 5-phenylazo derivatives preferentially. For example, the main product of the coupling of 2-benzylidene hydrazino-4-phenylselenazole with diazo-o-phenetidine is the 5-(o-ethoxyphenylazo)-selenazole (Scheme 371 ruby red prisms, m.p. 206°C. yield 67"o). A formazan is obtained as by-product. (See Section III.6) (43). 

In an alternative method, the senior component is regarded as substituted by RN=N—, this group R being named as a radical. Thus 2-(7-phenylazo-2-naphthylazo)anthracene is the name by this alternative method for the compound named anthracene-2-azo-2 -naphthalene-7 -azobenzene. 

The Chemicaly3.bstractIndexis 2,7-naphthalene-disulfonic acid, 4-amino-5-hydroxy-3-[[4 -[(4-hydroxyphenyl)azo] [l,l -biphenyl]-4-yl]azo]-6-(phenylazo)-, disodium salt. 

The reaction of 6-amino-5-(l,2-diethoxycarbonylhydrazino)pyrimidines with enamines represents another convenient method for the preparation of pteridines. Fusion of 5-(l,2-diethoxycarbonylhydrazino)-2,4,6-triaminopyrimidine (281) with an excess of mor-pholinocyclohexene leads to 2,4-diaminotetrahydrobenzo[g]pteridine, and with the morpholinoenamine (282) from 17/3-hydroxy-5a-androstan-3-one regioselective condensation to the fused pteridine (283) takes place in almost quantitative yield (equation 101) (71CC83). 6-Amino-5-nitroso- and 6-amino-5-phenylazo-pyrimidines react similarly, imitating the Timmis-type reaction (72CPB1428). 

Acyl-, 4-alkoxycarbonyl- and 4-phenylazo-pyrazolin-5-ones present the possibility of a fourth tautomer with an exocyclic double bond and a chelated structure. The molecular structure of (138) has been determined by X-ray crystallography (Table 5). It was shown that the hydroxy group participates in an intramolecular hydrogen bond with the carbonyl oxygen atom of the ethoxycarbonyl group at position 4 (8OCSCII21). On the other hand, the fourth isomer is the most stable in 4-phenylazopyrazolones (139), a chelated phenyl-hydrazone structure. 

The photolysis of the diazopyrazolone (369 X = N2, R = Me) in methanol yields two isomeric forms of methyl 3-phenylazo-2-butenoate (394) (80CC1263). The azo esters may arise via protonation of the carbene (395) with a concurrent opening of the ring by the nucleophilic solvent. 

The acetyl transfer reactions of acetylated pyrazolones (acylotropy) have been carefully studied by Arakawa and Miyasaka (74CPB207,74CPB214) (Section 4.04.2.1.3(x)). Methylation of 3-methyl-l-phenyl-4-phenylazo-5-pyrazolone (402) yields, depending on the experimental conditions, the N- and the O-methylated derivatives (483) and (484) (66BSF2990). These derivatives have been used as model compounds in a study of the tautomerism of (402) (structure 139 Section 4.04.1.5.2). 

Pyrazol-5-one, 3-methyl-1 -phenyl-4-phenylazo-methylation, 5, 264 Pyrazol-5-one, pyridyl-biological activity, 5, 295 Pyrazol-5-one, l-(4 -carbamoylphenyl)-3-methyl-azo pigments from, 1, 334 Pyrazol-5-one, 3-methyl-l-phenyl-azo dyes from, 1, 330 azo pigments from, 1, 334 Pyrazolones acetylated acylotropy, 5, 264 analytical applications, 5, 300 anions... 

Pyrimidine, 2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydro-conformation, 3, 62 synthesis, 3, 118 Pyrimidine, perhydro-polymers, 1, 313-314 Pyrimidine, phenyl-nitration, 3, 78 Pyrimidine, 4-phenyl-synthesis, 3, 72, 116 Pyrimidine, 5-phenylazo-synthesis, 3, 131 Pyrimidine, 4-phenyI-6-styryl-1-oxide... 

Pyrrolo[3,4-d]thiazole-4,6-dione, 5-ethyl-2-phenylazo-synthesis, 6, 1005 Pyrrolof 1,2-c]thiazoles reactions, 6, 1040 synthesis, 6, 988, 1047 Pyrrolo[2,1 - ijthiazoles synthesis, 6, 293, 992 1 /7,3/7-pyrrolo[l,2-c]thiazoles synthesis, 6, 1006 Pyrrolo[3,2-d]thiazoles synthesis, 6, 1009... 

Reaktions of complexes formation of In(III) with bis-(2,3,4-trioxy-phenylazo)benzidine (R) in presence of papaverine (Pap), dibazole (Dib), urotropine (Ur) has been studied by the spektrophotometric method. It has been established that the optimal conditions of complex formation for complexes of In(III) R-Pap, In(III) R-Dib and In(III) R-Ur are pH=2. 

Sudan I (Solvent Yellow 14, l-phenylazo-2-naphthol) [824-07-9] M 248.3, m 135 , Cl 12055, Xmax 476nm, pKe,( -9.0. Crystd from EtOH. 

Metanil Yellow (3[ 4-phenylamino phenylazo]-benzenesulfonic acid) [587-98-4] M 375.4, pKes, <0. Salted out from water three times with sodium acetate, then repeatedly extracted with EtOH [McGrew and Schneider, J Am Chem Soc 72 2547 7950]. 

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