The molecular formula of 6-methoxy-2-naphthaleneethanone is C 13 H 12 O 2 , the molecular weight is 200.
24, and the structural formula is
1.
Production principle
(1) It is obtained by methylation and acetylation with 2-naphthol as raw material
.
There are two types of methylation: the dimethyl sulfate method and the methanol sulfuric acid catalytic method, and the yield is generally 92%
.
Acetylation is completed by reacting with acetyl chloride using nitrobenzene as a solvent
.
(2) The 1-position of 2-naphthyl methyl ether is protected by bromine, so that the acetyl group of the acylation reaction is selectively entered into the 6-position, and the yield is almost quantitative
.
Finally, the bromine is removed by refluxing with xylene aluminum trichloride to obtain 6-methoxy-2-naphthaleneethanone
.
2.
Production process
In a four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, add 260g of 2-naphthol and 58mL of methanol , stir and raise the temperature to dissolve, add 14mL of concentrated sulfuric acid dropwise, and then continue to raise the temperature and reflux for 4h
.
Let stand to remove most of the acid solution, neutralize it with 20% sodium hydroxide solution to alkalinity, slowly reduce to room temperature, precipitate solids, filter, and wash with water until neutral
.
After drying, 59.
9 g of naphthyl methyl ether was obtained, with a melting point of 72.
5-73.
5°C
.
The alkaline mother liquor and the washing liquor are combined, the pH is adjusted to acidity with concentrated hydrochloric acid, the solid is separated out, filtered, washed with water to neutrality, dried, and 24.
8 g is recovered
.
In a 500 mL three-necked flask equipped with a stirrer, add 12.
5 g of naphthyl methyl ether and 250 mL of glacial acetic acid , stir to dissolve, and cool to 15°C
.
A mixture of 125 mL of glacial acetic acid and 13.
3 g of bromine was added dropwise, and the mixture was stirred for 10 minutes after the drop
.
Pour into 1500mL water, and precipitate crystals
.
Filter, wash with water to neutrality, and dry to obtain 18.
5 g of 1-bromo-2-methoxynaphthalene, with a yield of 98.
9% and a melting point of 84-85°C
.
Add 23.
7g of 1-bromo-2-methoxynaphthalene and 50mL of dichloroethane, dissolve by warming, and place in a dropping funnel for later use
.
Into a 250mL four-necked flask equipped with a stirrer, a thermometer and a drying tube, add 140mL of dichloroethane , and use an ice-salt bath to cool to an internal temperature of 0℃ under stirring
.
14.
7g of AlCl3 was added, and then 8.
7g of acetyl chloride was added dropwise, and the mixture was stirred for 10 minutes after the drop
.
Keeping the internal temperature at 0°C, add dropwise a solution of 1-bromo-2-methoxynaphthalene in dichloroethane
.
After dripping, continue to react at 0°C for 30 minutes
.
At this temperature, 24 mL of debromination agent xylene and 8 g of AlCl 3 were added
.
Keep the internal temperature (0±5)℃ and react for 20h
.
After the reaction is over, pour the materials into ice-hydrochloric acid-water, and stir while pouring
.
Let stand and separate the organic layer.
The aqueous layer was back extracted with 30 mL of dichloroethane.
The organic layers were combined and washed with 5% hydrochloric acid 50 mL×2, washed with 30 mL of 5% NaOH aqueous solution, and finally washed with 50 mL of water.
The organic layer was evaporated.
Dichloroethane was removed to dryness, and 31 g of yellow solid was obtained
.
It was recrystallized from methanol to obtain 15.
6 g of 6-methylchloro-2-naphthaleneethanone, the yield was 78%, and the melting point was 109-110°C
.
3.
Product use
6-Methoxy-2-forbidden ketone is an important intermediate for the synthesis of non-steroidal anti-inflammatory and analgesic drugs
.
