Sodium borohydride → 3-(4-Bromophenoxy)-6-methoxybenzo[b]thiophene 1,1-dioxide

HRID 632682Notes

Reaction equation

Br[C:2]1[S:6](=[O:8])(=[O:7])[C:5]2[CH:9]=[C:10]([O:13][CH3:14])[CH:11]=[CH:12][C:4]=2[C:3]=1[O:15][C:16]1[CH:21]=[CH:20][C:19]([Br:22])=[CH:18][CH:17]=1.[BH4-].[Na+]>CO.CS(C)=O>[Br:22][C:19]1[CH:20]=[CH:21][C:16]([O:15][C:3]2[C:4]3[CH:12]=[CH:11][C:10]([O:13][CH3:14])=[CH:9][C:5]=3[S:6](=[O:8])(=[O:7])[CH:2]=2)=[CH:17][CH:18]=1

Participants

Conditions

Temperature: 10 °C

Procedure

To a solution of 2-bromo-3-(4-bromophenoxy)-6-methoxy-benzo[b]thiophene 1,1-dioxide (180 g, 403 mmol) in MeOH (150 mL) and DMSO (1300 mL) at 0° C. (internal temperature was at 5° C.) was added the first portion of NaBH4 (15 g, 396.5 mmol). Internal temperature rose quickly to 40° C. and H2 gas release was observed. The mixture was stirred in an ice bath for 30 min (internal temperature cooled down to 10° C.). The second portion of NaBH4 (15.5 g, 409.7 mmol) was added. The resulting mixture was stirred for 30 minutes after which time the reaction was quenched with water (2000 mL) over 1 hour. The resulting precipitate was collected, air dried over 18 hours, then washed with heptane to afford 3-(4-bromophenoxy)-6-methoxybenzo[b]thiophene 1,1-dioxide as an off white solid which was used without further purification. 1H NMR (400 MHz, CDCl3) δ ppm=3.85 (s, 3 H), 5.38 (s, 1 H), 7.02-7.08 (m, 3 H), 7.22 (d, J=2.53 Hz, 1 H), 7.47-7.60 (m, 3 H).

Workup

customrose quickly to 40° C.
stirringThe resulting mixture was stirred for 30 minutes after which time the reaction
customwas quenched with water (2000 mL) over 1 hour
customThe resulting precipitate was collected
customair dried over 18 hours
washwashed with heptane

Sources & evidence

ORD record: ord-3463e38a353347089d1bb6dbd25f6054
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09321746B2

Reaction notes

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