Trimethylsilyldiazomethane → methyl 4H-thieno[3,2-b]pyrrole-5-carboxylate

HRID 1363266Notes

Reaction equation

[S:1]1[C:8]2[CH:7]=[C:6]([C:9]([OH:11])=[O:10])[NH:5][C:4]=2[CH:3]=[CH:2]1.[CH3:12][Si](C=[N+]=[N-])(C)C>CO>[S:1]1[C:8]2[CH:7]=[C:6]([C:9]([O:11][CH3:12])=[O:10])[NH:5][C:4]=2[CH:3]=[CH:2]1

Participants

Conditions

Temperature: 0 °C

Procedure

4H-thieno[3,2-b]pyrrole-5-carboxylic acid (3.0 g, 17.9 mmol) was dissolved in anhydrous MeOH (50.0 mL) and cooled to 0° C. A solution (45.0 mL, 2 M in hexanes) of trimethylsilyldiazomethane (45 mL) was added in portions and the yellow color of the TMSCH2N2 remained. Stirring was continued for 10 min and then the excess TMSCH2N2 was quenched with acetic acid (5.0 mL). The solvent was removed with N2 stream, and the residue was chromatographed over silica gel (5%-40%, 30 min, EtOAc in heptane) to give methyl 4H-thieno[3,2-b]pyrrole-5-carboxylate (2.8 g, 86% yield). 1H NMR (400 MHz, CD3Cl) δ ppm 3.90 (s, 3H) 6.95 (dd, J=5.32, 0.78 Hz, 1H) 7.13 (dd, J=1.88, 0.76 Hz, 1H) 7.33 (d, J=5.37 Hz, 1H) 9.02 (br. s, 1H).

Workup

customthe excess TMSCH2N2 was quenched with acetic acid (5.0 mL)
customThe solvent was removed with N2 stream
customthe residue was chromatographed over silica gel (5%-40%, 30 min, EtOAc in heptane)

Sources & evidence

ORD record: ord-639a84915ca14e369ce8dc4aaed361e0
Source dataset: uspto-grants-2011_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07884124B2

Reaction notes

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