Triethylamine → Phenyl pyridazin-4-ylcarbamate

温度

0 °C

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.

1. additionUpon completion of addition the reaction mixture
2. temperatureto warm to ambient temperature where it
3. concentrationThe reaction mixture was concentrated for three days
4. concentrationThe reaction mixture was concentrated under reduced pressure to a residue
5. filtrationfiltered
6. customto collect 1.9 grams of phenyl N-(4-pyridazinyl)carbamate
7. washThe filtrate was washed with water
8. dry with materialthen dried with magnesium sulfate
9. filtrationThe mixture was filtered
10. washFurther elution
11. concentrationconcentrated under reduced pressure

ORDレコード

ord-0ecc6e01233f4783bd7653a1c650ef52

出典データセット

uspto-grants-1988_04

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US04735650