Triethylamine → Phenyl pyridazin-4-ylcarbamate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A stirred suspension of 2.6 grams (0.027 mole) of 4-aminopyridazine (prepared as in Example 2, Step A) in 100 ml of tetrahydrofuran was cooled to 0° C. and 4.6 ml (0.033 mole) of triethylamine was added in one portion. A solution of 4.1 ml (0.033 mole) of phenyl chloroformate in tetrahydrofuran was added dropwise during a 30 minute period. Upon completion of addition the reaction mixture was allowed to warm to ambient temperature where it stirred for three days. The reaction mixture was concentrated for three days. The reaction mixture was concentrated under reduced pressure to a residue. The residue was taken up in 500 ml of chloroform and filtered to collect 1.9 grams of phenyl N-(4-pyridazinyl)carbamate; m.p. 184°-185° C. The filtrate was washed with water then dried with magnesium sulfate. The mixture was filtered and the filtrate placed on a column of silica gel. Further elution was accomplished using 10% methanol in methylene chloride. The appropriate fractions were combined and concentrated under reduced pressure to yield an additional 1.8 grams of phenyl N-(4-pyridazinyl)carbamate. The nmr spectra were consistent with the proposed structure. The reaction was repeated several times.

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