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

HRID 532739Notes

Reaction equation

HRID 532739 reaction equation
[C:1]([O:4][CH:5]1[C:9]2[N:10]=[CH:11][N:12]=[C:13](Cl)[C:8]=2[C@H:7]([CH3:15])[CH2:6]1)(=[O:3])[CH3:2].[C:16]([N:23]1[CH2:28][CH2:27][NH:26][CH2:25][CH2:24]1)([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17]>CN1C(=O)CCC1.C(OCC)(=O)C>[C:1]([O:4][CH:5]1[C:9]2[N:10]=[CH:11][N:12]=[C:13]([N:26]3[CH2:25][CH2:24][N:23]([C:16]([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17])[CH2:28][CH2:27]3)[C:8]=2[C@H:7]([CH3:15])[CH2:6]1)(=[O:3])[CH3:2]

Participants

5

Reactant 2

HCID 143452tert-Butyl piperazine-1-carboxylateHCID 58111335(5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetate

Product 1

HCID 59580360(R)-tert-butyl 4-(7-acetoxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylateYield 72.4%

Reagents, catalysts & solvents 2

HCID 8857Ethyl AcetateSolventHCID 13387N-methyl-2-pyrrolidoneSolvent

Conditions

Temperature
110 °C

Procedure

To a solution of (5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetate (0.5 g, 2.2 mmol) in NMP (10 mL) was added 1-Boc-piperazine (0.9 g, 4.8 mmol). The reaction mixture was heated to 110° C. for 12 hours. After cooling, the reaction mixture was diluted with ethyl acetate (200 mL) and washed with water (6×100 mL). The organic phase was dried and concentrated. The residue was purified by silica gel chromatography, eluting with ethyl acetate to give tert-butyl 4-((5R)-7-acetoxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (0.6 g, 72%). 1H NMR (CDCl3, 400 MHz) δ 8.60 (d, 1H), 6.05-5.90 (m, 1H), 3.80-3.30 (m, 9H), 2.84 (m, 1H), 2.20- (m, 1H), 1.49 (s, 9H), 1.29-1.20 (m, 3H). MS (APCI+) [M+H] +377. The resulting mixture of the diastereomers was purified by chiral separation HPLC (Chiralcel ODH column, 250×20 mm, Hexane/EtOH 60:40, 21 mL/min). The first peak (RT=3.73 min) gave the tert-butyl 4-((5R,7R)-7-acetoxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (0.144 g, 24%). The second peak (RT=5.66 min) gave the tert-butyl 4-((5R,7S)-7-acetoxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (0.172 g, 29%). MS (APCI+) [M+H] +377.

Workup

  1. temperatureAfter cooling
  2. washwashed with water (6×100 mL)
  3. customThe organic phase was dried
  4. concentrationconcentrated
  5. customThe residue was purified by silica gel chromatography
  6. washeluting with ethyl acetate

Sources & evidence

ORD record
ord-d590bcd4589f4cec9c5da6ce2806743d
Source dataset
uspto-grants-2014_10
Patent number
US08853199B2

Reaction notes

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