Boron tribromide → ethyl 5-(3,4-dihydroxy-5-nitrophenyl)-1-methyl-2-(2-(trifluoromethyl)pyridin-3-yl)-1H-pyrrole-3-carboxylate

HRID 62007Notes

Reaction equation

C([O:8][C:9]1[CH:10]=[C:11]([C:26]2[N:30]([CH3:31])[C:29]([C:32]3[C:33]([C:38]([F:41])([F:40])[F:39])=[N:34][CH:35]=[CH:36][CH:37]=3)=[C:28]([C:42]([O:44][CH2:45][CH3:46])=[O:43])[CH:27]=2)[CH:12]=[C:13]([N+:23]([O-:25])=[O:24])[C:14]=1[O:15]CC1C=CC=CC=1)C1C=CC=CC=1.B(Br)(Br)Br>ClCCl>[OH:8][C:9]1[CH:10]=[C:11]([C:26]2[N:30]([CH3:31])[C:29]([C:32]3[C:33]([C:38]([F:41])([F:40])[F:39])=[N:34][CH:35]=[CH:36][CH:37]=3)=[C:28]([C:42]([O:44][CH2:45][CH3:46])=[O:43])[CH:27]=2)[CH:12]=[C:13]([N+:23]([O-:25])=[O:24])[C:14]=1[OH:15]

Participants

Conditions

Temperature: -78 °C

Procedure

A solution of ethyl 5-(3,4-bis(benzyloxy)-5-nitrophenyl)-1-methyl-2-(2-(trifluoromethyl)pyridin-3-yl)-1H-pyrrole-3-carboxylate (0.189 g, 0.30 mmol) in dichloromethane (10 mL) was cooled to −78° C. with stirring and treated under argon with boron tribromide (0.30 g, 1.21 mmol). The resulting deep purple suspension was then allowed to stir at room temperature for one hour before cooling again to −78° C. The mixture was quenched by the careful addition of methanol. After stirring at room temperature for thirty minutes, the volatiles were evaporated and the residue stirred with 2 N hydrochloric acid (5 mL) for thirty minutes. The resulting solid was filtered off, washed with water (25 mL) and then cold isopropanol (5 mL) to give ethyl 5-(3,4-dihydroxy-5-nitrophenyl)-1-methyl-2-(2-(trifluoromethyl)pyridin-3-yl)-1H-pyrrole-3-carboxylate as a yellow solid, 0.126 g (93%).

Workup

stirringto stir at room temperature for one hour
customThe mixture was quenched by the careful addition of methanol
stirringAfter stirring at room temperature for thirty minutes
customthe volatiles were evaporated
stirringthe residue stirred with 2 N hydrochloric acid (5 mL) for thirty minutes
filtrationThe resulting solid was filtered off
washwashed with water (25 mL)

Sources & evidence

ORD record: ord-37b58679fb494567940c125fdcb6b039
Source dataset: uspto-grants-2016_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09446012B2

Reaction notes

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