3-Hydroxy-2-naphthoic acid → Naphthalen-1(2H)-one
Reaction equation
[C:1](=[O:4])([O-])[O-].[Na+].[Na+].NC1C=CC2=NC(=O)N=C2C=1.O[C:19]1[C:20](C(Cl)=O)=[CH:21][C:22]2[C:27]([CH:28]=1)=C[CH:25]=[CH:24][CH:23]=2.OC1C(C(O)=O)=CC2C(C=1)=CC=CC=2>C1(C)C(C)=CC=CC=1.CN1CCCC1=O>[C:1]1(=[O:4])[C:27]2[C:22](=[CH:21][CH:20]=[CH:19][CH:28]=2)[CH:23]=[CH:24][CH2:25]1Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 100 °C
Procedure
1750 ml of N-methylpyrrolidone are initially introduced into a 10 1 four-necked flask having a dropping funnel, reflux condenser, internal thermometer and stirrer. 291.5 g (2.75 mol) of sodium carbonate are added to this. 372.5 g (2.5 mol) of 5-aminobenzimidazolone are then added at about 25° C. 3181.8 g of 3-hydroxy-2-naphthoyl chloride (from 494.0 g (2.63 mol) of 3-hydroxy-2naphthoic acid) in xylene are metered into the suspension thus obtained with stirring in the course of 6.5 h at 25°-28° C. After addition is complete, the mixture is subsequently stirred at room temperature for 30 min. The precipitated product is filtered off with suction (suction time: 50 min) and the filter cake is washed in 10 portions with a total of 2150.0 g=2500 ml of xylene. 2500 ml of water are initially introduced into a 6 l four-necked flask having a stirrer, internal thermometer and distillation bridge having a 1 l one-necked flask as a receiver. The filter cake is then introduced. 200.0 g of sodium carbonate are then added and the mixture is heated to 100° C. Xylene and water distill off. The product is filtered off with suction at 100° C. and the suction filter cake is washed several times with a total of 6250 ml of water until neutral. 1571.4 g of naphthalone are obtained in water-moist form. After drying the filter cake at 100° C./100 mmHg, 681.7 g (2.135 mol) of 3-hydroxy-N-benzimidazolon-5-yl-2naphthamide are obtained; this corresponds to a yield of 85.4% of theory based on 5-aminobenzimidazolone.
Workup
- temperaturereflux condenser
- customthus obtained
- additionAfter addition
- stirringthe mixture is subsequently stirred at room temperature for 30 min
- filtrationThe precipitated product is filtered off with suction (suction time: 50 min)
- washthe filter cake is washed in 10 portions with a total of 2150.0 g=2500 ml of xylene
- addition2500 ml of water are initially introduced into a 6 l four-necked flask
- distillationinternal thermometer and distillation bridge
- additionThe filter cake is then introduced
- addition200.0 g of sodium carbonate are then added
- distillationXylene and water distill off
- filtrationThe product is filtered off with suction at 100° C.
- filtrationthe suction filter cake
- washis washed several times with a total of 6250 ml of water until neutral
Sources & evidence
- ORD record
- ord-68b45b1148f842e5bb041c04e5fcdeef
- Source dataset
- uspto-grants-1998_05
- Patent number
- US05756757
Reaction notes
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