1H-1,2,4-Triazole

CN 4-[4-[4-[4-[[2-(2,4-dichlorophenyl)-2-( 1H-1,2,4-triazol-1 -ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]-l-piperazinyl]phenyl]-2,4-dihydro-2-(l-methylpropyl)-3//-l,2,4-triazol-3-one... 

Ethyl a,2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-0X0-1H-1,2,4-triazol-1-yl]-4-fluorobenzene-propanoate... 

Dihydro-3-methoxy-4-methyl-5-oxo-A/-[[2-(tri-fluoromethoxy)phenyl]sulfonyl]-1H-1,2,4-triazole-1-carboxamide, sodium salt... 

Table 34 Cyclization of selenosemicarbazides to give 3-alkylseleno-1H-1,2,4-triazole derivatives (Equation 52)...

C[ Na2S/l,4-Dioxan/H20 80s 45 min 5- ( 4-Amino-phenyl )-l-(4-chlor-phenyl) -1H-1,2,4-triazol 80 l... 

Among the nitrated and/or nitrited derivatives only 3-amino-a-as(or 1H-1,2,4)-triazole nitrate and 3-0 i tram ino-a-as (or lH-l l-triazole were found in the literature... 

The nitrogen heteroatoms in imidazole and some closely related heterocycles can stabilize a carbene center at the 2-position (97AG(E)2162). Thus, 1,3-disubstituted imidazole-2-ylidenes (163)-(170), l,3-dimesitylimidazoline-2-ylidene (171), 1,3,4-triphenyl-1H-1,2,4-triazole-5-ylidene (172), and their silylene (173) and germylene (174) analogues are stable (in the absence of oxygen and moisture) solids with definite melting points, which can be recrystallized from appropriate hydrocarbon solvents. The exception is carbene (163) which is an unstable liquid however, it is stable in solution. 

Amino-5 imino-3-methyldihydro- a-sym-triazole or 4-Amino-5-imino-3-methyldihydro-1H-1,2,4-triazole [4-Amino-3-methyl-l. 2.4-triazolon-(5)-imid, in Ger], HN C-NH-N, ... 

Amino-5-methyl-a-sym-triazole or 3-Amino-5-methyl- 1H-1,2,4-triazole, H,C C-NH-N... 

Amino-a-sym-triazole Nitrate or 3-Amino-1H-1,2,4-triazole Nitrate, HC-NH-N + HN03,... 

Chemical Name 1H-1,2,4-Triazole, l-((2-(2,4-dichlorophenyl)-l,3-dioxolan-2-yl)methyl)-... 

Hydrochloric acid Acetic acid Sodium hydroxide 1H-1,2,4-Triazole Sodium... 

A mixture of 1.6 parts of 1H-1,2,4-triazole, 54 parts of N.N-dimethylformamide and 45 parts of benzene is stirred and refluxed for 2 h. After cooling, 0.78 parts of sodium hydride dispersion 78% are added and the whole is stirred for 30 min at room temperature. Then there are added 8.9 parts of cis-2-(bromomethyl)-2-(2,4-dichlorophenyl)-l,3-dioxolan-4-ylmethyl benzoate and stirring is continued overnight at 150°C. The reaction mixture is cooled and poured onto water. The product is extracted three times with benzene. The combined extracts are washed twice with water, dried, filtered and evaporated, yielding 8.5 parts of cis-[2-(2,4-dichlorophenyl)-2-(lH-l,2,4-triazol- l-ylmethyl)-l,3-dioxolan-4-ylmethyl]benzoate as a residue. 

To a stirred solution of 28.4 parts of 1H-1,2,4-triazole in 135 parts of N,N-dimethylformamide were added 11.4 parts of a sodium hydride dispersion 80% under nitrogen atmosphere. After stirring for 1 hour at room temperature, a solution of 40 parts of 6-[chloro(4-chlorophenyl)-methyl]-l-methyl-lH-benzotriazole in 90 parts of N,N-dimethylformamide was added to the mixture. The whole was stirred for 1 hour at 60°C. The reaction mixture was diluted with 50 parts of water and the whole was evaporated. The residue was extracted with ethyl acetate. The extract was washed with water, dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (99 1 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 2-propanone and l,l -oxy-bis-ethane (ether). The product was filtered off and dried, yielding 13 parts (29.2%) of 6-[(4-chlorophenyl)-(lH-l,2,4-triazol-l-yl)methyl]-l-methyl-lH-benzotriazole MP 178.9°C. A resolution of enantiomers any usual method gave crystals from 2-propanol, MP 130-135°C. [a]D20 = 8.0° (plus or minus) (c = 10 in CH3OH). 

The l,4-diacyl-3-acylamino-5-phenyl-4,5-dihydro-1H-1,2,4-triazole (99) was generated by the ring-closure of a guanidinylhydrazone with acetic anhydride in ca. 80% yield. The structure of the triazole was confirmed by spectroscopy and x-ray analysis [95M733], The N-benzyl triazoline (100) was prepared by reaction of N-benzylidinebenzylamine with a hydrazonyl halide with K,CO, in benzene, followed by 2 eq of Et,N for 1 h, in 75% yield [95ZOB308]. 

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