Trimethyl borate → {1-(tert-Butoxycarbonyl)-5-[4-(tert-butoxycarbonyl)piperazine-1-sulfonyl]-1H-indol-2-yl}boronic acid

HRID 2211941Notes

Reaction equation

[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([S:14]([C:17]2[CH:18]=[C:19]3[C:23](=[CH:24][CH:25]=2)[N:22]([C:26]([O:28][C:29]([CH3:32])([CH3:31])[CH3:30])=[O:27])[CH:21]=[CH:20]3)(=[O:16])=[O:15])[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[Li]C(C)(C)C.C[O:39][B:40](OC)[O:41]C>C1COCC1>[C:29]([O:28][C:26]([N:22]1[C:23]2[C:19](=[CH:18][C:17]([S:14]([N:11]3[CH2:12][CH2:13][N:8]([C:6]([O:5][C:1]([CH3:4])([CH3:3])[CH3:2])=[O:7])[CH2:9][CH2:10]3)(=[O:16])=[O:15])=[CH:25][CH:24]=2)[CH:20]=[C:21]1[B:40]([OH:41])[OH:39])=[O:27])([CH3:32])([CH3:31])[CH3:30]

Participants

Conditions

Temperature: 0 °C

Procedure

A solution of the tert-butyl 5-{[4-(tert-butoxycarbonyl)piperazin-1-yl]sulfonyl}-1H-indole-1-carboxylate (2-4, 1.06 g) in THF (55 mL) was stirred at −78° C. and treated with t-BuLi (1.7M, 2.68 mL, 4.55 mmol). After stirring for 45 minutes, the solution was treated with trimethylborate (640 μL, 5.69 mmol). The solution was warmed to 0° C. and stirred for 10 min, then partitioned between ethyl acetate (2×100 mL) and saturated NH4Cl solution (100 mL). The combined organics were dried over Na2SO4, filtered and concentrated to provide 1-(tert-butoxycarbonyl)-5-{[4-(tert-butoxycarbonyl)piperazin-1-yl]sulfonyl}-1H-indol-2-ylboronic acid (2-5) as a yellow foam. LRMS m/z: Cal'd for C22H32BN3O8S (M+H) 509.39, found 510.1.

Workup

stirringstirred for 10 min
custompartitioned between ethyl acetate (2×100 mL) and saturated NH4Cl solution (100 mL)
dry with materialThe combined organics were dried over Na2SO4
filtrationfiltered
concentrationconcentrated

Sources & evidence

ORD record: ord-3df5616b985c4c999d3214a2cea20f2d
Source dataset: uspto-grants-2006_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07101884B2

Reaction notes

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