N-bromobutanimide → HCID 59648627, compound

HRID 1363276Notes

Reaction equation

S1C2NC(C(OCC)=O)=CC=2C=C1.CCCC[N+](CCCC)(CCCC)CCCC.[F-].C1C(=O)N([Br:39])C(=O)C1.[Br:40][C:41]1[C:42]2[CH:53]=[CH:52][S:51][C:43]=2[NH:44][C:45]=1[C:46]([O:48][CH2:49][CH3:50])=[O:47]>C(Cl)Cl.CCOC(C)=O>[Br:40][C:41]1[C:42]2[CH:53]=[CH:52][S:51][C:43]=2[NH:44][C:45]=1[C:46]([O:48][CH2:49][CH3:50])=[O:47].[Br:39][C:52]1[S:51][C:43]2[NH:44][C:45]([C:46]([O:48][CH2:49][CH3:50])=[O:47])=[C:41]([Br:40])[C:42]=2[CH:53]=1

Participants

Conditions

Temperature: 23 °C

Procedure

To a solution of ethyl 6H-thieno[2,3-b]pyrrole-5-carboxylate (0.55 g, 2.82 mmol) in DCM (10 mL) was added TBAF (1.0 M THF, 4.2 mL) followed by NBS (0.55 g, 3.1 mmol). The resulting mixture was allowed to stir at 23° C. for 1 h in the dark at which time the entire reaction mixture was placed on a silica gel column. Flash column chromatography (0-100% EtOAc in hexanes) affords one major peak containing a mixture of starting material, ethyl 4-bromo-6H-thieno[2,3-b]pyrrole-5-carboxylate, and 2,4-dibromo products. Separation of the desired products from the byproduct by RP-HPLC (10-100% gradient 0.1% formic acid in H2O to CH3CN over 10 min) afforded ethyl 4-bromo-6H-thieno[2,3-b]pyrrole-5-carboxylate (0.30 g, 39% yield) and ethyl 2,4-dibromo-6H-thieno[2,3-b]pyrrole-5-carboxylate (183 mg, 18%). Ethyl 2,4-dibromo-6H-thieno[2,3-b]pyrrole-5-carboxylate: 1H NMR (400 MHz, CD3OD) δ (ppm) 6.95 (s, 1H), 4.32 (q, J=4.6 Hz, 2H), 1.36 (t, J=7.0 Hz, 3H). LCMS m/e=351 (M+H).

Workup

customthe entire reaction mixture
additioncontaining
customSeparation of the desired products from the byproduct by RP-HPLC (10-100% gradient 0.1% formic acid in H2O to CH3CN over 10 min)

Sources & evidence

ORD record: ord-52c05eee00884d36b19eacb905bd091d
Source dataset: uspto-grants-2011_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07884124B2

Reaction notes

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