Methyl iodide → 6-Methoxy-2-methylbenzo[b]thiophene

HRID 1825057Notes

Reaction equation

[CH2:1]([Li])CCC.[CH3:6][O:7][C:8]1[CH:9]=[CH:10][C:11]2[CH:15]=[CH:14][S:13][C:12]=2[CH:16]=1.CI>C1COCC1.C([O-])(O)=O.[Na+]>[CH3:6][O:7][C:8]1[CH:9]=[CH:10][C:11]2[CH:15]=[C:14]([CH3:1])[S:13][C:12]=2[CH:16]=1

Participants

Conditions

Temperature: -10 °C

Procedure

A 2.5 M solution of n-butyllithium in hexanes (20 ml, 50 mmole) was added under argon to a solution of 6-methoxybenzo[b]thiophene 1a (3.68 g, 22.4 mmole) in THF (150 ml) at −75°. After stirring at −75° for a further 30 minutes, the cooling bath was exchanged and the reaction warmed to −10° C. prior to addition of CH3I (4.2 ml, 9.58 g, 67 mmole). The resultant mixture was stirred at 0° C. for an additional 30 minutes, then allowed to gradually warm to room temperature before diluting with saturated NaHCO3 (150 ml). The layers were separated and the aqueous phase was extracted with EtOAc (2×100 ml). The combined organic extracts were dried over Na2SO4 and concentrated, in vacuo, to give 4.2 g of an amber oil which was purified by silica gel chromatography. Elution with hexane: Et2O (98:2) and evaporation of the appropriate fractions gave 3.639 (91%) of a colourless oil. 1H NMR (DMSO-d6) δ 7.57 (1H, d, J=8.7 Hz), 7.43 (1H, d, J=2.4 Hz), 6.99 (1H, s), 6.92 (1H, dd, J=2.4, 8.7 Hz), 3.78 (3H, s), 2.50 (3H, s). Anal. Calcd. for C10H10OS: C, 67.38; H, 5.66; S, 17.99. Found: C, 67.42; H, 5.74; S, 17.87.

Workup

temperatureto gradually warm to room temperature
customThe layers were separated
extractionthe aqueous phase was extracted with EtOAc (2×100 ml)
dry with materialThe combined organic extracts were dried over Na2SO4
concentrationconcentrated, in vacuo

Sources & evidence

ORD record: ord-a1a94f14a94f40aaa6948aed6e8b804c
Source dataset: uspto-grants-2006_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07045528B2

Reaction notes

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