반응 #2260927

반응 방정식

hydrochloric acid

2,7-dibromonaphthalene

n-butyllithium

trimethyl borate

→

7-bromonaphthalene-2-boronic acid

수율 75.0%

용매

tetrahydrofuran

hexane

반응 조건

후처리

1. 1
   workup.STIRRINGby stirring at −78° C. for 2 hours
2. 2
   workup.STIRRINGthis solution was stirred for 18 hours while the temperature
3. 3
   온도was raised to room temperature
4. 4
   workup.STIRRINGthe mixture was stirred for 1 hour
5. 5
   기타Then, this mixture solution was separated into an organic layer
6. 6
   추출Organic substances were extracted with ethyl acetate from the obtained aqueous layer
7. 7
   기타had been first obtained
8. 8
   세척the mixture was washed with saturated brine
9. 9
   건조dried by addition of anhydrous magnesium sulfate to the organic layer
10. 10
    기타Then, the filtrate obtained by gravity filtration
11. 11
    농축was concentrated
12. 12
    기타to give a white solid
13. 13
    세척The obtained white solid was washed with a mixed solvent of hexane and toluene

실험 절차

First, 3.0 g of 2,7-dibromonaphthalene was placed into a 500-mL three-neck flask, and the air in the flask was replaced with nitrogen. To this compound was added 150 mL of tetrahydrofuran (THF), and this solution was stirred at −78° C. for 20 minutes. Then, 6.4 mL of a 1.7M hexane solution of n-butyllithium (n-BuLi) was dripped into this mixture solution, followed by stirring at −78° C. for 2 hours. After the predetermined time had elapsed, 2.4 mL of trimethyl borate was added to the mixture and this solution was stirred for 18 hours while the temperature was raised to room temperature. After the predetermined time had elapsed, 60 mL of 1.0M hydrochloric acid was poured into this solution, and the mixture was stirred for 1 hour. Then, this mixture solution was separated into an organic layer and an aqueous layer. Organic substances were extracted with ethyl acetate from the obtained aqueous layer. The solution of the extract was combined with the organic layer that had been first obtained, and the mixture was washed with saturated brine and dried by addition of anhydrous magnesium sulfate to the organic layer. Then, the filtrate obtained by gravity filtration was concentrated to give a white solid. The obtained white solid was washed with a mixed solvent of hexane and toluene, whereby 7-bromonaphthalene-2-boronic acid was obtained (as a white powder in 75% yield). The synthesis scheme of Step 1 is illustrated in the following (a-5).

출처