4- Formyl-l,2,3-triazoles

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

Auf analoge Weise erhalt man u.a. 5-Amino-1 -methyl-4-formyl-l,2,3-triazol (68% d.Th. F 182,5°, Zens.). 

Under these conditions, the even less reactive 5-aminomethyl-3-benzyl-4-methylamino-l,2,3-triazole gave some of the 5-formamidomethyl analog, but no 9-benzyl-3,6-dihydro-3-methyl-8-azapurine (69). An attempt to cyclize this formyl derivative by heating at 200°C caused it to undergo a Dimroth retrogression to 4-benzylamino-5-formamidomethyl-3-methyl-1,2,3-triazole other attempts to close the ring also failed.64... 

In the still more 7t-deficient 1,2,3-triazole series (see 20), several 4-amino-5-formyl derivatives resisted both direct acylation and acetal formation. A successful alternative was to form intermediates with side chains conjugated to the nucleus. For example, 1- and 2-methyl-, as well as 3-benzyl-4-amino-l,2,3-triazole-5-aldehydes reacted with a cold mixture of dimethylformamide and phosphoryl chloride to give excellent yields of, e.g., 3-benzyl-4-dimethyl-aminomethyleneamino-l,2,3-triazole-5-aldehyde (84). This was converted to 9-benzyl-8-azapurine (see 21) in excellent yield by refluxing in methanolic ammonium acetate.87 In a variation of this reaction, an imidate (85) replaced the amidine (84) as intermediate. Thus, 4-amino-l-methyl-l,2,3-triazole-5-aldehyde and triethyl orthoacetate, refluxed for 2 hr, gave an excellent yield of 4-ethoxyethylideneamino-l,2,3-triazole-5-aldehyde (85), cyclized, by stirring in cold ethanolic ammonia, to 2,7-dimethyl-8-azapurine (good yield).87... 

All remaining Anil Syntheses involving 1,2,3-triazoles have been performed with Schiff s bases derived from 4-formyl- or 2- or 4-(p-formylphenyl)-2/f-l,2,3-triazole and chloroanilines, which react with both carbocyclic and heterocyclic / -tolyl derivatives. Carbocyclic... 

H-< 1,2,4-Oxadiazolo[4.3-a]-l,3,5-triazin) 5,7-Dimethyoxy-3,3-dimethyl- E16c, 221 (aus Azido-1.3,5-triazin) Pyrimidin 5-Ethoxycarbonyl-4-hydrazino-2-hydroxy-6-methyl-E16a, 766 (SH - NH-NH2) 2H-l,2,3-Triazol 5-(Diethoxy-methylen-amino)-4-formyl- E4, 565 [C(OR)4 + Amin]... 

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). 

Triazole has been prepared by the oxidation of substituted 1,2,4-triazoles, by the treatment of urazole with phosphorus pentasulfide, by heating equimolar quantities of formyl-hydrazine and formamide, by removal of the amino function of 4-amino-l,2,4-triazole, by oxidation of l,2,4-triazole-3(5)-thiol with hydrogen peroxide, by decarboxylation of 1,2,4-triazole-3(5)-carboxylic acid, by heating hydrazine salts with form-amide,by rapidly distilling hydrazine hydrate mixed with two molar equivalents of formamide, i by heating N,N -diformyl-hydrazine with excess ammonia in an autoclave at 200° for 24 hours, and by the reaction of 1,3,5-triazine and hydrazine monohydrochloride. ... 

A derivative of a hitherto unknown nucleus was produced when 4-amino-5-aminomethyl-3-methyltriazole was refluxed with carbon disulfide and triethylamine in pyridine, which yielded 3-methyl-3,7-dihydro-l,2,3-triazolo-[4,5-d][l,3]thiazine-5-thione (98) (3 hr, 53%) the 3-benzyl analog was made similarly (63%) [80JCS(P1)2009]. Cyclization of 4-anilino-5-ethoxycarbonyltriazole with polyphosphoric acid produced 1 f/-triazolo-[4,5-h]quinol-4-one (99) [80EUP(A)2562]. Similarly, ring closure of 4-(2-pyridylamino)triazole-5-carboxylic acid (or its esters) gave l//-pyrido-[l,2-a]-l,2,3-triazolo[4,5-d]pyrimidin-4-one (100) (77GEP2757929). 4-Amino-5-formyl-3-methyltriazole and pentane-2,4-dione, set aside in 20% sulfuric acid, yielded 3,5-dimethyl-3//-l,2,3-triazolo [4,5-6] pyridin-6-yl... 

Reactions of 2-formyl-galactal, presented as an unsaturated sugar derivative with push-pull functionalization, with guanidinium and amidinium salts, respectively were carried out imder basic conditions to furnish the substituted 5-( 1,2,4-tri-O-benzyl-D-lyxo- l,2,3,4-tetrahydroxy-butyl)pyrimidines 92 (Fig. 16). Treatment of the 2-formyl pentose glycals with 2-aminobenzimid-azole and 3-amino-1,2,4-triazole, respectively afforded 3-(l,2,4-tri-0-benz-yl-D-lyxo-l,2,3,4-tetrahydroxy-butyl)benzo[4,5]imidazo[l,2-a]pyrimidine 94... 

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