Hydrochloric Acid → Ethyl 5-bromo-2-methyl-2-phenyl-pentanoate

HRID 873288Notes

Reaction equation

HRID 873288 reaction equation
[C:1]1([CH2:7][C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[Li+].[CH3:14]C([N-]C(C)C)C.CI.[Br:23][CH2:24][CH2:25][CH2:26]Br.[NH4+].[Cl-].Cl>C1COCC1.CN1C(=O)N(C)CCC1>[Br:23][CH2:24][CH2:25][CH2:26][C:7]([CH3:14])([C:1]1[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1)[C:8]([O:10][CH2:11][CH3:12])=[O:9]

Participants

9

Reactant 6

HCID 313Hydrochloric AcidHCID 6328Methyl iodideHCID 7590Ethyl phenylacetateHCID 80011,3-DibromopropaneHCID 25517Ammonium ChlorideHCID 2724682Lithium diisopropylamide

Product 1

HCID 23431358Ethyl 5-bromo-2-methyl-2-phenyl-pentanoateYield 113.9%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 816462(1H)-Pyrimidinone, tetrahydro-1,3-dimethyl-Solvent

Procedure

Under Ar-atmosphere, to a solution of ethyl phenylacetate (42.4 g, 0.26 mol) and DMPU (5 mL) in THF (250 mL) was added dropwise a solution of LDA (2 M, 135 mL, 0.27 mol) at −78° C. The mixture was stirred for 2 h, before methyl iodide (41.40 g, 0.29 mol) was added in a single portion. The mixture was stirred overnight and allowed to warm to room temperature. After cooling to −78° C., 1,3-dibromopropane (72.7 g, 0.36 mol) was added and the mixture was allowed to stir overnight, gradually warming to room temperature. The mixture was hydrolyzed by consecutive addition of ice (200 g), saturated aqueous NH4Cl solution (400 mL), and concd HCl (100 mL), and extracted with ethyl acetate (2×200 mL). The organic layers were dried over over anhydrous MgSO4, and distilled under vacuum to give 205b as colorless oil (88.6 g, 59%). Bp 123-128° C./0.25 mmHg. 1H NMR (CDCl3): 7.20-7.10 (m, 5H), 4.12 (q, 2H, J=7.2), 3.35 (t, 2H, J=6.9), 2.18-2.00 (m, 2H), 1.77-1.72 (m, 2 μl), 1.56 (s, 3H), 1.18 (t, 3H, J=6.9). 13C NMR (CDCl3): 175.9, 143.4, 128.5, 126.9, 126.0, 61.0, 49.8, 38.2, 34.0, 28.5, 22.8, 14.2.

Workup

  1. additionwas added in a single portion
  2. temperatureAfter cooling to −78° C.
  3. stirringto stir overnight
  4. temperaturegradually warming to room temperature
  5. extractionextracted with ethyl acetate (2×200 mL)
  6. dry with materialThe organic layers were dried over over anhydrous MgSO4
  7. distillationdistilled under vacuum

Sources & evidence

ORD record
ord-a86aa3f8275247f4955a4db095755b53
Source dataset
uspto-grants-2015_03
Patent number
US08975300B2

Reaction notes

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