Propylamine → Ethyl 2-(tert-butoxycarbonylamino)-2-((propylamino)methyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

HRID 579517Notes

Reaction equation

HRID 579517 reaction equation
[C:1]([O:5][C:6]([NH:8][C:9]([CH:28]=O)([CH2:15][CH2:16][CH2:17][CH2:18][B:19]1[O:23][C:22]([CH3:25])([CH3:24])[C:21]([CH3:27])([CH3:26])[O:20]1)[C:10]([O:12][CH2:13][CH3:14])=[O:11])=[O:7])([CH3:4])([CH3:3])[CH3:2].[CH2:30]([NH2:33])[CH2:31][CH3:32].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].C(=O)(O)[O-].[Na+]>ClCCCl.C(O)(=O)C>[C:1]([O:5][C:6]([NH:8][C:9]([CH2:28][NH:33][CH2:30][CH2:31][CH3:32])([CH2:15][CH2:16][CH2:17][CH2:18][B:19]1[O:23][C:22]([CH3:25])([CH3:24])[C:21]([CH3:26])([CH3:27])[O:20]1)[C:10]([O:12][CH2:13][CH3:14])=[O:11])=[O:7])([CH3:2])([CH3:4])[CH3:3]

Participants

7

Reactant 4

HCID 7852PropylamineHCID 516892Sodium BicarbonateHCID 5049666Sodium triacetoxyborohydrideHCID 86663719Ethyl 2-(tert-butoxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

Product 1

HCID 66833266Ethyl 2-(tert-butoxycarbonylamino)-2-((propylamino)methyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateYield 34.4%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidCatalystHCID 111,2-DichloroethaneSolvent

Procedure

A slurry of ethyl 2-(tert-butoxycarbonylamino)-2-formyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate (172 mg, 0.42 mmol) and propylamine (40 μL, 0.49 mmol, 1.3 equiv) in 1,2-dichloroethane (3 mL) was treated with sodium triacetoxyborohydride (352 mg, 1.66 mmol, 4 equiv). Acetic acid (2 drops, ca 3-5 equiv) was added and the mixture stirred at room temperature for 17 hours then 60° C. for 1 hour. Once the reaction was complete, saturated aqueous sodium bicarbonate was added and the solution was extracted with dichloromethane. The organic extracts were washed with saturated aqueous NaCl, dried over MgSO4, filtered and concentrated. Purification by flash chromatography (0-60% ethyl acetate in hexane) gave ethyl 2-(tert-butoxycarbonylamino)-2-((propylamino)methyl)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate as an oil (66 mg, 34%). 1H NMR (CDCl3, 400 MHz) δ 4.16 (m, 2H), 3.5-3.3 (m, 2H), 3.2 (br m, 2H), 2.9 (m, 1H), 1.8-1.6 (m, 4H), 1.5-1.4 (m, 2H), 1.38 (s, 9H), 1.36-1.3 (m, 3H), 1.22 (t, J=7.2 Hz, 3H), 1.18 (s, 12H), 1.05 (m, 1H), 0.75 (t, J=7.4 Hz, 3H), 0.68 (t, J=7.5 Hz, 2H). ESI+ MS: obsd m/z 457 (M+H)+.

Workup

  1. wait60° C. for 1 hour
  2. extractionthe solution was extracted with dichloromethane
  3. washThe organic extracts were washed with saturated aqueous NaCl
  4. dry with materialdried over MgSO4
  5. filtrationfiltered
  6. concentrationconcentrated
  7. customPurification by flash chromatography (0-60% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-e555187a9d864aeeaf347bbfe254d15b
Source dataset
uspto-grants-2015_05
Patent number
US09040703B2

Reaction notes

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