1.2.4- Triazin-5-ones, 6-trifluoromethyl

Trifluoromethyl-l,2,4-triazines and 1,2,4-triazin-5-ones are versatile precursors for azetidines and pyridines by cycloaddition reactions. Enhancement of reactivity was observed through the presence of the trifluor-omethyl group (88CPB3354). 

A new cyclization method for [l,2,4]triazolo[5,l-c]triazines (ring system 26) starting from trifluoromethylated 1,2,3-triketones and resulting in formation of 4,7-dihydro derivatives has recently been published <2005JFC1230>. The structure of one representative derivative has also been investigated by X-ray crystallography. 

Hydrazono-l,l,l-trifluoroalkan-2-ones (4) react with aldehydes in the presence of aqueous ammonia to yield 5-trifluoromethyl-2,3-dihydro-1,2,4-triazines which can be oxidised to give 5-trifluoromethyl-l,2,4-triazines (5) or 5-trifluoromethyl-2,5-dihydro-5-hydroxy-1,2,4-triazines (6) [94H(39)155], whilst hydrazines react with a-lactams to give 1,2,4-triazine-3,6-diones [95JOC4121 95JOC5992] (Scheme 3). 

In the third experiment, rotation away from continuous EPTC + dietholate in 1984 to no herbicide, trifluralin (2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine) + metribuzin (4-amino-6-(l, l-dimethylethyl)-3-(met.hylthio)-l, 2,4 -triazin-5(4H) one), alachlor + atrazine, or cycloate + atrazine increased the persistence of EPTC + dietholate at 14 and 21 DAT in 1985. Rotation with trifluralin + metribuzin or alachlor + atrazine was more effective than rotation with weedy check or cycloate + atrazine. However, the differences were not statistically significant. All rotated herbicide treatments had higher EPTC recoveries than the untreated plot (Table III). The results indicated that 1 year rotations resulted in partial to complete elimination of enhanced biodegradation for this herbicide. 

The sterically crowded 3-amino-2//-aziridines (461) react with 5-trifluoromethyl-l,3,4-oxadiazol-2(3H)-om (462) to give 1 1 adducts of type (463) 6-amino-4,5-dihydro-l,2,4-triazin-3(27/)-ones (464) are formed as minor products (5-31%) (Scheme 83) <90HCA492>. 

Methyl-3-phenyl-5-[ trifluoromethyl)phenyl])-4 (1 H )-pyridinone 4 Amino--6-tert-butyl-3-(methylthio)-as-triazin-5(4 H )one... 

A slow stream of HGl-gas passed under N2 through a soln. of 2,2,2-trifluoro-ethylidenebenzylamine in anhydrous ether until it is no longer consumed, ether and excess HGl removed in a stream of N2, the residue dissolved in dimethyl-formamide (dried over molecular sieves), dicyandiamide added with stirring in one portion, and stirring continued 20 min. 4,6-diamino-l-benzyl-l,2-dihydro-2-trifluoromethyl-l,3,5-triazine hydrochloride. Y 73%. F. e. s. H. Newman and E. L. Moon, J. Org. Ghem. 29, 2061 (1964). 

Hydrazono-1,1,1 -trifluoroalkan-2-ones 35 prepared from 1,1,1 -trifluoroalkane-2,3-diones 34 reacted with several aldehydes in the presence of aqueous NH4OH to afford 5-trifluoromethyl-2,3-dihydro-l,2,4-triazines, of which oxidation gave 5-trifluoromethyl-1,2,4-triazines 36 (Scheme 16) [26],... 

Katagiri N, Watanabe H, Kaneko C (1988) Cyclocondensations in synthesis. XXXVII. Synthesis of 6-trifluoromethyl-l,2,4-triazines and -l,2,4-triazin-5-ones and their pericyclic reactions with olefins. Chem Pharm Bid 36 3354—3372... 

N-[2,4-dimethyl-5-[[(trifluoromethyl)-sulfonyl]amino]phenyl]acetamide 4-chlorophenyl methylcarbamate 4-amino-4,5-dihydro-3-methyl-6-phenyl-l,2,4-triazin-5-one... 

N-(2,6-dimethylphenyl)- N- (1 -pyrazol-1 -ylmethyl)acetamide (9cl) 4-chloro-5-(dimethylamino)-2-[(3-trifluoromethyl)phenyl]-3(2//)-pyridazinone N-2-benzothiazolyl- N, iV - dimethylurea 2-(3,4-dichlorophenyl)-4-methyl-l,2,4-oxadiazolidine-3,5-dione N-(3-methoxypropyl)-iV -(l-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine 4 methoxy-3,3 -dimethylbenzophenone N -(4-bromophenyl)- JV-methoxy- N- methylurea 2-chloro- N-(2-ethyl-6-methylphenyl)- N- (2-methoxy-l-methylethyl)acetamide N -(3-chloro-4-methoxyphenyl)-JV,JV-dimethylurea 4-amino-6-(l,l-dimethylethyl)-3-(methylthio)-l,2,4-triazin-5 (4H) -one... 

A (1/7-imidazol-l-yl) silver species (55) has been postulated as the key intermediate in the 3-l-2-cycloaddition reaction of diazoalkanes (54) with benzynes yielding 2-aryl-2H-indazoles (56) (Scheme 18). The 3-I-2-cycloaddition reaction of 3-trifluoromethyl-4-diazopyrazolinones with dialkyl acetylene dicarboxylates, in refluxing toluene, produced spiro 3/f-pyrazole adducts that rearranged to the trifluoromethyl-substituted pyrazolo[l,5-fi(][l,2,4]triazin-7-ones. ° The 1,3-dipolar cycloaddition reaction of aromatic thioketones (58) with 2-aza-1,3-dicarbonyl compounds (57), at 20-50 C, yielded thiadiazoline adducts (59) that readily eliminate nitrogen to produce oxathioles (60) in moderate yields (up to 70%) (Scheme 19). ... 

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