Water → HCID 59556541, compound

HRID 1172956Notes

Reaction equation

HRID 1172956 reaction equation
[O:1]=[C:2]1[NH:7][CH2:6][CH2:5][N:4]([C:8]([O:10][CH2:11][C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)=[O:9])[CH2:3]1.[C:18]([O-])([O-])=O.[Na+].[Na+].F[B-](F)(F)F.C[O+](C)C.O>C(Cl)Cl>[CH2:11]([O:10][C:8]([N:4]1[CH2:3][C:2]([O:1][CH3:18])=[N:7][CH2:6][CH2:5]1)=[O:9])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1

Participants

6

Reactant 4

HCID 962WaterHCID 10340Sodium CarbonateHCID 736777Benzyl 3-oxopiperazine-1-carboxylateHCID 2735153Oxonium, trimethyl-, tetrafluoroborate(1-) (1:1)

Product 1

HCID 59556541HCID 59556541, compoundYield 95%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of benzyl 3-oxopiperazine-1-carboxylate (20.50 g, 10.67 mmol) in CH2Cl2 (100 ml) was cooled to 0° C. and treated with Na2CO3 (23.0 g, 217 mmol) for 10 minutes. Neat trimethyloxonium tetrafluoroborate (5.50 g, 37.2 mmol) was added in one portion, then the reaction is allowed to warm to room temperature for 6 hours. The reaction was poured into water (100 ml), and the layers were separated. The aqueous layer was re-extracted aqueous with 50 ml CH2Cl2 and the combined organic layers were washed with brine (100 ml). The organic layer was dried over sodium sulfate, filtered and concentrated to yield 5-methoxy-3,6-dihydro-2H-pyrazine-1-carboxylic acid benzyl ester (2.51 g, 95%) as an oil. LCMS (Table 1, Method a) Rt=3.00 min, m/z 249.24 (M+H)+−; 1H NMR (400 MHz, DMSO-d6) δ 7.36 (m, 5H), 5.16 (s, 2H), 3.96 (s, 2H), 3.68 (s, 3H), 3.54 (s, 2H), 3.47 (m, 2H)

Workup

  1. customthe layers were separated
  2. extractionThe aqueous layer was re-extracted aqueous with 50 ml CH2Cl2
  3. washthe combined organic layers were washed with brine (100 ml)
  4. dry with materialThe organic layer was dried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-d38907601290498eba8cddd489fbb655
Source dataset
uspto-grants-2010_11
Patent number
US07834039B2

Reaction notes

Loading…