3-(5-Nitro-1-methyl-2-imidazolyl)-6-amino-s-triazolo[4,3-b]pyridazine → 3-(5-Nitro-1-methyl-2-imidazolyl)-6-ethoxymethyleneamino-s-triazolo[4,3-b]pyridazine
Reaction equation
[N+:1]([C:4]1[N:8]([CH3:9])[C:7]([C:10]2[N:14]3[N:15]=[C:16]([NH2:19])[CH:17]=[CH:18][C:13]3=[N:12][N:11]=2)=[N:6][CH:5]=1)([O-:3])=[O:2].[CH:20]([O-])([O-])[O:21][CH2:22][CH3:23]>>[N+:1]([C:4]1[N:8]([CH3:9])[C:7]([C:10]2[N:14]3[N:15]=[C:16]([N:19]=[CH:20][O:21][CH2:22][CH3:23])[CH:17]=[CH:18][C:13]3=[N:12][N:11]=2)=[N:6][CH:5]=1)([O-:3])=[O:2]Participants
Procedure
1.15 g. 3-(5-nitro-1-methyl-2-imidazolyl)-6-amino-s-triazolo[4,3-b]pyridazine was stirred with 15 ml. ethyl orthoformate and 7.5 m. acetic anhydride at a bath temperature of 130° C., then evaporated in a vacuum at 70° C. to give a residue of crude 3-(5-nitro-1-methyl-2-imidazolyl)-6-ethoxymethyleneamino-s-triazolo[4,3-b]pyridazine. A sample thereof, triturated with ethanol, melted at 134° - 135° C. The residue thus obtained was dissolved in 20 ml. of a mixture of isopropanol and dioxan (7:3) and 2.3 ml. 4-methylpiperazine added thereto at 20° C., while stirring. The crystals formed were filtered off with suction after about 15 minutes, washed with isopropanol and water and dried in a vacuum for 2 hours at 120° C. There was thus obtained 1.22 g. of the desired 3-(5-nitro-1-methyl-2-imidazolyl)-6-(4-methyl-piperazin-1-yl-methyleneamino)-s-triazolo[4,3-b]pyridazine which melts at 219° - 222° C.
Workup
- customacetic anhydride at a bath temperature of 130° C., then evaporated in a vacuum at 70° C.
Sources & evidence
- ORD record
- ord-ee094ce0ea1c4960b760b92d931e1a50
- Source dataset
- uspto-grants-1977_02
- Patent number
- US04006141
Reaction notes
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