Hydrochloric Acid → 2,6-Dichlorobenzoxazole
Reaction equation
P(Cl)(Cl)(Cl)(Cl)Cl.[Cl:7][C:8]1[CH:17]=[CH:16][C:11]2[NH:12][C:13](=O)[O:14][C:10]=2[CH:9]=1.[ClH:18]>ClC1C=CC=CC=1Cl>[Cl:18][C:13]1[O:14][C:10]2[CH:9]=[C:8]([Cl:7])[CH:17]=[CH:16][C:11]=2[N:12]=1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
1 litre of o-dichlorobenzene and 625 g (3 moles) of phosphorus pentachloride are heated to 160° C., then 169.5 g (1 mole) of solid 6-chlorobenzoxazolin-2-one are introduced in small portions over the course of 60 minutes, vigorous evolution of hydrogen chloride occuring for a short time after each portion. The mixture is then stirred for a further 15 minutes at 150°-160° C., and then cooled to 0° C., whereupon the major part of the excess pCl5 crystallises out. The phosphorus pentachloride precipitate is filtered off with suction, Washed with a little cold o-dichlorobenzene, and the filtrate is fractionated under reduced pressure. phosphorus oxychloride distils over first, then o-dichlorobenzene together with the remainder of the excess phosphorus pentachloride, and last, at about 110° C. and 17.3 mbar, 2,6-dichlorobenzoxazole. About 136 g of 2,6-dichlorobenzoxazole of melting point 48-49° C. are obtained. GC purity 99.7%. yield: 72% of theory.
Workup
- customcrystallises out
- filtrationThe phosphorus pentachloride precipitate is filtered off with suction
- washWashed with a little cold o-dichlorobenzene
- customphosphorus oxychloride distils over first, then o-dichlorobenzene together with the remainder of the excess phosphorus pentachloride
- customat about 110° C.
Sources & evidence
- ORD record
- ord-1aa93cb356df4e08a62dc564bc23f97b
- Source dataset
- uspto-grants-1987_12
- Patent number
- US04714766
Reaction notes
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