Triethylamine → tert-butyl 4-((5R,7R)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

HRID 75404Notes

Reaction equation

HRID 75404 reaction equation
[N+:1]([C:4]1[CH:12]=[CH:11][C:7]([C:8](Cl)=[O:9])=[CH:6][CH:5]=1)([O-:3])=[O:2].[OH:13][CH:14]1[C:18]2[N:19]=[CH:20][N:21]=[C:22]([N:23]3[CH2:28][CH2:27][N:26]([C:29]([O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[O:30])[CH2:25][CH2:24]3)[C:17]=2[C@H:16]([CH3:36])[CH2:15]1.CCN(CC)CC.C([O-])(O)=O.[Na+]>C(Cl)Cl>[CH3:36][C@H:16]1[C:17]2[C:22]([N:23]3[CH2:28][CH2:27][N:26]([C:29]([O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[O:30])[CH2:25][CH2:24]3)=[N:21][CH:20]=[N:19][C:18]=2[C@H:14]([O:13][C:8](=[O:9])[C:7]2[CH:6]=[CH:5][C:4]([N+:1]([O-:3])=[O:2])=[CH:12][CH:11]=2)[CH2:15]1.[CH3:36][C@H:16]1[C:17]2[C:22]([N:23]3[CH2:28][CH2:27][N:26]([C:29]([O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[O:30])[CH2:25][CH2:24]3)=[N:21][CH:20]=[N:19][C:18]=2[C@@H:14]([O:13][C:8](=[O:9])[C:7]2[CH:6]=[CH:5][C:4]([N+:1]([O-:3])=[O:2])=[CH:12][CH:11]=2)[CH2:15]1

Participants

7

Reactant 4

HCID 8471TriethylamineHCID 85024-Nitrobenzoyl chlorideHCID 516892Sodium BicarbonateHCID 59580348(R)-tert-butyl 4-(7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

Product 2

HCID 59580346tert-butyl 4-((5R,7R)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylateHCID 59580349tert-butyl 4-((5R,7S)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

4-Nitrobenzoyl chloride (15.78 g, 85.03 mmol) was added to a 0° C. solution of (R)-tert-butyl 4-(7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (25.85 g, 77.30 mmol) and NEt3 (11.73 g, 16.16 mL, 115.9 mmol) in DCM (400 mL). The reaction mixture was stirred for 5 minutes. The mixture was then warmed to room temperature and stirred overnight (17 hours), after which saturated NaHCO3 was added. The reaction mixture was stirred for 10 minutes and transferred to a separatory funnel. The organic layers were collected, and the aqueous extracts were washed with DCM (2×). The combined organic extracts were dried (Na2SO4), filtered, and concentrated. The crude was flashed on silica loaded with 7:1 hexanes:ethyl acetate (gradient 5:1 hexanes:ethyl acetate to 2:1 hexanes:ethyl acetate to 1:1 hexanes:ethyl acetate). Some clean tert-butyl 4-((5R,7R)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate, some clean tert-butyl 4-((5R,7S)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate and some mixed fractions were isolated. The mixed fractions were recolumned and combined with the previously isolated material to give tert-butyl 4-((5R,7R)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (14.27 g, 38%) and tert-butyl 4-((5R,7S)-5-methyl-7-(4-nitrobenzoyloxy)-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (12.58 g, 34%). The use of 4-bromobenzoyl chloride has been shown to offer slightly better separation of the isomers.

Workup

  1. stirringstirred overnight (17 hours)
  2. stirringThe reaction mixture was stirred for 10 minutes
  3. customtransferred to a separatory funnel
  4. customThe organic layers were collected
  5. washthe aqueous extracts were washed with DCM (2×)
  6. dry with materialThe combined organic extracts were dried (Na2SO4)
  7. filtrationfiltered
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-16f9e9260c074a81afdcec4b5569e257
Source dataset
uspto-grants-2014_09
Patent number
US08835434B2

Reaction notes

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