2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → Tert-butyl isopropyl(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiazol-2-yl)carbamate

HRID 1958478Notes

Reaction equation

HRID 1958478 reaction equation
Br[C:2]1[S:6][C:5]([N:7]([CH:15]([CH3:17])[CH3:16])[C:8](=[O:14])[O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[N:4][CH:3]=1.C([Li])CCC.C(O[B:27]1[O:31][C:30]([CH3:33])([CH3:32])[C:29]([CH3:35])([CH3:34])[O:28]1)(C)C>C1COCC1>[C:10]([O:9][C:8](=[O:14])[N:7]([CH:15]([CH3:17])[CH3:16])[C:5]1[S:6][C:2]([B:27]2[O:31][C:30]([CH3:33])([CH3:32])[C:29]([CH3:35])([CH3:34])[O:28]2)=[CH:3][N:4]=1)([CH3:13])([CH3:12])[CH3:11]

Participants

5

Reactant 3

HCID 50177412-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolaneHCID 58688351Tert-butyl 5-bromothiazol-2-yl(isopropyl)carbamateHCID 178418339Butyllithium

Product 1

HCID 58688452Tert-butyl isopropyl(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiazol-2-yl)carbamateYield 48.6%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution of tert-butyl 5-bromothiazol-2-yl(isopropyl)carbamate (7.5 g, 23.3 mmol) in THF (50 mL) was added n-butyllithium (1.6 M in hexane, 21.8 mL) dropwise at −78° C. The solution turned orange. The solution was stirred at −78° C. for minutes before 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (6.49 g, 34.9 mmol) was added dropwise. The mixture was stirred at −78° C. for 2 hours then warmed to room temperature. The reaction was quenched with 1:1 ammonium chloride/water (50 mL). The resulted mixture was extracted with ethyl acetate (100 mL). The organic layer was separated, washed with water, brine and concentrated. To the brown solid residue was added hexane (30 mL). The mixture was filtered and the filter cake was washed with hexane (20 mL) and dried to give as a yellow solid (4.17 g, 48% yield). LCMS (Conditions C): 3.21 min (RT); (M+H)+=247.12 (40%), 245.12 (50%), 233.10 (75%), 231.10 (100%). 1H NMR, 400 MHz, CDCl3: δ 7.95 (s, 1 H), 5.37 (m, 1 H), 1.60 (s, 9 H), 1.44 (d, 6.7 Hz, 6 H), 1.34 (s, 12 H).

Workup

  1. additionwas added dropwise
  2. temperaturethen warmed to room temperature
  3. customThe reaction was quenched with 1:1 ammonium chloride/water (50 mL)
  4. extractionThe resulted mixture was extracted with ethyl acetate (100 mL)
  5. customThe organic layer was separated
  6. washwashed with water, brine
  7. concentrationconcentrated
  8. additionTo the brown solid residue was added hexane (30 mL)
  9. filtrationThe mixture was filtered
  10. washthe filter cake was washed with hexane (20 mL)
  11. customdried

Sources & evidence

ORD record
ord-fdcfbd0eed164943ac9592b50ea90cd0
Source dataset
uspto-grants-2013_04
Patent number
US08410128B2

Reaction notes

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