Imidoylamidines

In a related cyclocondensation six-membered rings containing the NSeN functionality may be prepared by the reaction of imidoylamidines with SeCU (Eq. 2.10). 

Of the thiatriazines, the 1,2,4,6-system has been the most studied. There has been particular interest in TV-alkyl-1,2,4,6-thiatriazine 1,1-dioxides because of their herbicidal, fungicidal, and histamine H2-antagonist activity (86TL123,87S170). The preparation of l-chloro-l,2,4,6-thiatriazines (576) by reaction of imidoylamidines (575) with an excess of sulfur dichloride was reported (80JOU1303). 

The preparation of l-chloro-l,2,4,6-thiatriazines (51) by reaction of imidoylamidines (50) with excess of sulfur dichloride was reported in 1980 <80JOU1303>. 

Synthesis of the 3,5-dipyridylthiatriazinyl radical 93 requires reaction of the imidoylamidine 90 with S2CI2 in boiling MeCN to afford the bis(N-bridgehead-l,2,5-thiadiazolium) dication 91, which on treatment with Ph3Sb undergoes a two-electron reduction to afford the 1,2,4,6-thia-triazine 92. Subsequent oxidation with half an equivalent of I2 in the presence of base, affords radical 93 (Scheme 13) (2014CC4934). 

Cyanoformamidines 10 1,1 -Cyanohydrazines a-Cyanohydrazines 10 a-Cyanohydrazones Diamidides N-Imidoylamidines 20 a,a-Diaminonitriles N, N - Dicy anamides Enazides Enetriazenes... 

Continued interest (Vol. 1, p. 259) has been shown in the preparation of sy/M-triazines bearing fluorinated substituents. A review of perfluoroalkylene-triazine elastomers has been published two separate approaches (Scheme 59), the acylation-cyclodehydration of imidoylamidines, formed from amidines and nitriles, and the free-radical coupling of preformed triazine derivatives, have been used successfully to produce polymers of good linearity. 

Methods of preparing the polymers have been reviewed (Young, 1972) but no one method is at present wholly satisfactory. Probably the most thoroughly studied method involves the ring closure of poly(imidoylamidine) with, for example, the anhydride of a perfluorocarboxylic acid. 

The main synthetic approaches to trifluoromethyl substituted 1,3,5-triazines are trimerization of CF3CN [58], cyclocondensation process based on imidoylamidines [59], cyanoguanidines [60] or biguanides [61 ] and also fluorination of trichloromethyl-1,3,5-triazines [47,62],... 

By the method of acylation-cyclodehydration of imidoylamidines 771,3,5-triazines 78 have been prepared (Scheme 33) [59]. Synthesis of 2-trifluoromethyl-4,6-bis(2,3-dichloro-l,l,2,3,3-pentafluoro)-l,3.5-triazine from 3,4-dichloro-2,2,3,4,4-pentafluo-robutyronitril, NH3 and trifluoroacetic anhydride was reported [65],... 

A number of patents and papers dealing with the synthesis of fluorinated jym-triazines and related triazine-linked polymers via cyclotrimerization of fluoroalkyl cyanides,or cyclization reactions of per- and poly-fluoro-imidoylamidines (see p. 15), and the use of tris(perfluoroalkyl)-s3 /n-... 

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