2,1,3-Triazole, 2-phenyl-4-formyl

Interesting synthetic applications of these degenerate rearrangements are the preparation of l-alkyl-4-formyl-l,2,3-triazole 110 from l-phenyl-4-... 

Uber eine Relais-Synthese lassen sich aus 4-(a-Amino-benzy]idenamino)-4H-l,2,4-triazolcn mit Carbonsaureanhydriden oder Carbonsaure-chloriden in Dimethylformamid 2-substi-tuierte 1,3,4-Oxadiazole im Eintopfverfahren herstellen552,553. Diese Reaktion verlauft iiber Acyl-hydrazone von 1-Formyl-3-phenyl-l,2,4-triazol, dessen Pyrolyse ebenfalls gute Aus-beuten liefert552. Mit dieser Methode konnten einige 1,3,4-Oxadiazole in besseren Ausbeuten und groBerer Reinheit als nach anderen Verfahren synthetisiert werden. 

The preparation and reactions of the azine, phenylhydrazone, and phenyl-semicarbazone of 4-amino-5-formyl-2-methyltriazole proceeded normally. One acetal has been prepared as follows. 4-Amino-3-benzyl-5-formyltriazole and boron trifluoride (as diethyl ether complex), stirred in methanol, gave 4-amino-3-benzyl-5-dimethoxymethyltriazole (20°C, 6 hr, 53%) and a dimeric by-product, 4-amino-3-benzyl-5-(3-benzyl-5-dimethoxytriazol-4-ylimino-methyl)triazole [73JCS(P1)2037]. The amino group in 4-aminotriazole-5-carbaldehydes lends itself readily to the formation of amidines and imidates (Section III,B,1), but it resists acylation. 

In 1944, Hann and Hudson found that, when refluxed with cupric sulfate, osazones are converted into colorless triazole derivatives which they designated osotriazoles. They determined the structure of the d-orahmo-hexulose derivative by means of the following reactions (1) it gave a tetraacetate and a tetrabenzoate which could be saponified to the parent osotriazole, indicating the presence of four free hydroxyl groups therein (2) on periodate oxidation, 3 moles of oxidant were consumed per mole of (71), giving 1 mole of formaldehyde, 2 moles of formic acid, and a known compound, 4-formyl-2-phenyl-l, 2,3-triazole (72). 

The sugar residues in osotriazoles can be readily acetylated, benzoylated (see Table II, p. 117), or p-toluenesulfonated. Further, as previously stated, osotriazoles can be oxidized with sodium periodate or red lead to give 4-formyl-2-phenyl-l,2,3-triazole (3), or with 20% nitric acid, aqueous potassium permanganate, or ceric sulfate to give 2-phenyl-l,2,3-triazole-4-carboxylic acid (5). 

Bevington and coworkers have suggested a scheme for determining the distribution of radioactive carbon in labeled n-glucose, using the degradation of D-arabino-hexose phenylosotriazole. The scheme is based on the periodate oxidation of n-ambmo-hexose phenylosotriazole and d-arabino-hexose phenylosotriazole 6-benzoate. The former gives formaldehyde from C-6, formic acid from C-4 and C-5, and 4-formyl-2-phenyl-1,2,3-triazole from C-1, C-2, and C-3. This latter aldehyde can be further... 

The synthesis of 4-carboxyl-1,2,3-triazoles and derivatives has been an active field of study, and the variety of methods developed is impressive. One of the earliest reactions is the oxidation, usually with silver oxide, of the formyl group (Eq. 21). Sheehan and Robinson have reported the first example of phenyl azide addition in which both isomeric products were isolated (Eq. 22), and they demonstrated the structures of 4.2-1 and 4.2-2 by oxidation. Similar results were obtained using the diethylacetal of propy-nal followed by hydrolysis. 

Osotriazoles of diketones previously had been described by von Pech-mann 2 0) who obtained them by the oxidation of the corresponding di-hydrazones. The corresponding osotriazoles of the sugars are formed directly by the action of copper sulfate. The formation of the phenyl-D-glucoso-triazole (II) from glucose phenylosazone (I) is illustrated. Its structure is demonstrated by oxidation with periodic acid to the 2-phenyl-4-formyl-osotriazole (III) which is identical with the product obtained previously by von Pechmann from mono-0-acetyldinitrosoacetone phenylhydrazone (IV). 

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