반응 #2376754

반응 방정식

Ethyl propiolate

4,5-methylenedioxy-2-nitrobenzaldehyde

acetic acid

diisopropylamine

butyllithium

→

ethyl 4-hydroxy-4-(4,5-methylenedioxy-2-nitrophenyl)-2-butynoate

수율 119.0%

용매

tetrahydrofuran

tetrahydrofuran

water

tetrahydrofuran

반응 조건

후처리

1. 1
   workup.STIRRINGthe mixture was stirred at -78° C. for additional 1.5 hr
2. 2
   workup.ADDITIONwas then added
3. 3
   추출followed by extraction with ethyl acetate
4. 4
   세척The organic layer was washed with dilute hydrochloric acid, water
5. 5
   건조It was then dried over anhydrous magnesium sulfate
6. 6
   기타The solvent was removed under reduced pressure

실험 절차

To a solution of diisopropylamine (6.8 ml, 49.0 mol) in tetrahydrofuran (80 ml) was added, at -78° C. under an argon atmosphere, a 1.5 N butyllithium (30.7 ml, 46.0 mmol). The mixture was stirred for one hr. Ethyl propiolate (3.9 ml, 38.4 mmol) and a solution of 4,5-methylenedioxy-2-nitrobenzaldehyde (5.0 g, 25.6 mmol) in tetrahydrofuran (50 ml) were added in that order to the reaction mixture, and the mixture was stirred at -78° C. for additional 1.5 hr. A solution of acetic acid (8.0 ml, 139 mmol) in tetrahydrofuran (20 ml) was then added to the reaction mixture, water was then added thereto, followed by extraction with ethyl acetate. The organic layer was washed with dilute hydrochloric acid, water, a saturated aqueous sodium bicarbonate solution, and saturated brine in that order. It was then dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure to give ethyl 4-hydroxy-4-(4,5-methylenedioxy-2-nitrophenyl)-2-butynoate as an oil (8.93 g). Ethyl 4-hydroxy-4-(4,5-methylenedioxy-2-nitrophenyl)-2-butynoate thus prepared was dissolved in toluene (75 ml), 4-methoxybenzylazide (14.9 g, 91.1 mmol) was added to the solution, and the mixture was stirred at 100° C. overnight. The reaction mixture was cooled to room temperature, and the solvent was removed under reduced pressure. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:2) to give a 1:1 mixture of ethyl 4-(1-hydroxy-(4,5-methylenedioxy-2-nitrophenyl)methyl)-1-(4-methoxybenzyl)-1,2,3-triazole-5-carboxylate (a-1: low polar product (LP)) and ethyl 5-(1-hydroxy-(4,5-methylenedioxy-2-nitrophenyl)methyl)-1-(4-methoxybenzyl)-1,2,3-triazole-4-carboxylate (a-2: high polar product (MP)) (6.42 g, 55%).

출처