Acetyl chloride → (R)-tert-butyl 8-(acetoxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylate

HRID 1521515Notes

Reaction equation

HRID 1521515 reaction equation
[OH:1][CH2:2][C:3]1[C:4]([S:26]([CH3:29])(=[O:28])=[O:27])=[CH:5][C:6]2[N:10]3[CH2:11][CH2:12][N:13]([C:18]([O:20][C:21]([CH3:24])([CH3:23])[CH3:22])=[O:19])[C@H:14]([CH:15]([CH3:17])[CH3:16])[C:9]3=[N:8][C:7]=2[CH:25]=1.CCN(CC)CC.[C:37](Cl)([CH3:39])=[O:38].CCOC(C)=O>C(Cl)Cl>[C:37]([O:1][CH2:2][C:3]1[C:4]([S:26]([CH3:29])(=[O:27])=[O:28])=[CH:5][C:6]2[N:10]3[CH2:11][CH2:12][N:13]([C:18]([O:20][C:21]([CH3:23])([CH3:24])[CH3:22])=[O:19])[C@H:14]([CH:15]([CH3:16])[CH3:17])[C:9]3=[N:8][C:7]=2[CH:25]=1)(=[O:38])[CH3:39]

Participants

6

Reactant 4

HCID 6367Acetyl chlorideHCID 8471TriethylamineHCID 8857Ethyl AcetateHCID 89815566(R)-tert-butyl 8-(hydroxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylate

Product 1

HCID 89815908(R)-tert-butyl 8-(acetoxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylateYield 81.1%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a 50 mL round-bottomed flask containing (R)-tert-butyl 8-(hydroxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylate (236 mg, 0.558 mmol) in CH2Cl2 (5 mL) was added Et3N (169 mg, 1.67 mmol) and AcCl (87 mg, 1.12 mmol) under N2. The mixture was stirred at rt for 10 min. The reaction was quenched with water (20 mL). The aqueous layer was extracted with CH2Cl2 (3×20 mL). The combined organic layers were washed with water (25 mL) and brine, and then dried over anhydrous Na2SO4. The mixture was filtered and the filtrate was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel eluting with PE: EtOAc 8:1-4:1 to give (R)-tert-butyl 8-(acetoxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylate (210 mg, 81.1% yield) as a yellow solid.

Workup

  1. customThe reaction was quenched with water (20 mL)
  2. extractionThe aqueous layer was extracted with CH2Cl2 (3×20 mL)
  3. washThe combined organic layers were washed with water (25 mL) and brine
  4. dry with materialdried over anhydrous Na2SO4
  5. filtrationThe mixture was filtered
  6. customthe filtrate was evaporated under reduced pressure
  7. customThe residue was purified by column chromatography on silica gel eluting with PE

Sources & evidence

ORD record
ord-4ea56c4a3b164b85bcee2bb3c2560a78
Source dataset
uspto-grants-2015_07
Patent number
US09073931B2

Reaction notes

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