Guanidines 1,3,5-triazines, 2-amino

Reaction of 2,3-dichlorobenzoyl chloride with cyanide ion leads to the corresponding benzoyl cyanide (141). Condensation of that reactive intermediate with aminoguanidine 142 leads to the hydrazone-like product 143. Treatment with base results in addition of one of the guanidine amino groups to the nitrile function and formation of the 1,2,4-triazine ring. The product, lamo-trigine (144), is described as an anticonvulsant agent [31]. 

The main starting compound is the labeled nitroguanidine 257 obtained from guanidine with isotope-labeled potassium nitrate. Reduction of 257 to hydrazine carboximidamide 258 was carried out with zinc and, then, ring closure to 3-amino[l,2,4]triazole 259 was carried out using formic acid. Finally, the ring closure to form the [l,2,4]triazine ring - similar to other procedures presented in Scheme 54 - was perfected by reaction with nitrous acid followed by treatment with ethyl nitroacetate to 260. 

Triazin 6-Amino-4-(4-niethoxy-phenyl-2-methyl- E9c, 719 (Ar-CO-NH-CS-CH3 + Guanidin)... 

Amino and nitro groups in different rings may be annulated by heating with aqueous potassium hydroxide in pyridine. The triazine oxide ring is also formed when an o-nitro-guanidine is heated with aqueous carbonate. 

Reaction of acyl cyanides with amidrazones or guanidin-2-amine has been used for the synthesis of l,2,4-triazin-5-amines 11,172 or l,2,4-triazine-3,5-diamines 12. The reaction proceeds via 4-amino-2,3-diazabutadiene-l-carbonitriles.333- 336... 

Heating the potassium salt 15 of guanidine-1,2-dicarbonitrile in aqueous solution with hydrogen sulfide in an autoclave at 80-150°C affords 4,6-diamino-l,3,5-triazine-2-thiol (thioammeline, 16) and 6-amino-l,3,5-triazine-2,4-dithiol (dithioammelide, 17).455... 

Syntheses of this type are from urea, thiourea, and amidine and guanidine derivatives. Ureas give tetrahydro-l,3,5-triazin-2-ones on reaction with a primary amine (1 equiv.) and aqueous formaldehyde (2-30 equiv.). In general, alkyl and aryl amines, unsaturated amines, amino alcohols, and a-amino esters form triazinone derivatives (Equation (43)). Methyl and benzyl have proven to be the most useful urea substituents with respect to high yields and product solubility. N,N -Dicyclohexyl- and A,A -diphenyl-urea gave poor yields of triazinone <90TL2109>. 

Triazines (205) are formed from the reaction of guanidine and methyl ( )-3-amino-2-phenyl-... 

A new synthesis of 6-arylamino-2-heteroarylimino-l,2-dihydro-l,3,5-triazines from 2,4-bis-(heteroarylimino)-l,3-diazetidines and amidines has been developed by Molina et al. The formation of the triazines was explained as an initial addition of the imino nitrogen of the amidine to the exocyclic C=N bond, followed by formation of an open chain intermediate. This intermediate cyclized, followed by elimination of 4-amino-6-methyl-3-methylthio-l,2,4-triazin-5(47/)-one to give the triazine product (Scheme 62) <87S150>. 1,3,5-Triazines (207) and (208) have been prepared from 2-acylimino-l,3-thiazetidines (204) by treatment with iso thioureas or guanidines respectively (Scheme 63) <91JHC177>. 

The Wittig-type reactions of iminophosphoranes with isocyanates and related compounds have also been extensively used in heterocyclic synthesis. Examples include the preparations of the mesoionic [l,3,4]thiadiazolo[2,3-c][l,2,4]triazines (210) from (209), 0 bicyclic guanidines, e.g. (212), from (211), naphthypyridines (215), (216), and (217) from (213) and (214), 2 pyrido[l,2-f]pyrimido-[4,5-d)pyrimidines (218), 7H-pyrido-[4,3-c]- (219) and 10H-pyrido[3,4-b]- (220) carbazoles, tricyclic fused 2,4-diimino-l,3-diazetidines (222) from the bisiminophosphorane (221), benzotriazepines (225) from (223) and (224), 6 and mesoionic thiazolo-[2,3-b]-1,3,4-thiadiazoles (227) and N,N-bisheteroarylamines from the iminophosphorane (226), derived from 3-amino-4-phenylthiazole-2(3H)-thione. The carbodiimides (229), prepared from the iminophosphorane (228), can be converted into quinolines or a-carboline derivatives depending on the nature of the isocyanate used in the reaction with (228) and the reactions of iminophosphoranes (230) and (231) with aryl and styryl isocyanates provide one-pot syntheses of quinoline, a-carboline, and quinindoline derivatives. 9... 

No new synthetic route to monosubstituted 1,3,5-triazines has been reported. The reaction of 1,3,5-triazine with imidates gives monoalkyl- or aryl-l,3,5-triazines <1961JOC2784>. 2-Amino-l,3,5-triazines are best prepared by reaction of triformidomethane with a formyl guanidine <1963AGE655>. 

The same authors reported that the reaction of nitronaphthalenes 73 with guanidines in the presence of t-BuOLi gave amino-1,2,4-triazines 74 fused with naphthalene [65] (Scheme 36). 

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