Acetic Anhydride → (5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetate

HRID 81007Notes

Reaction equation

HRID 81007 reaction equation
[Cl:1][C:2]1[N:7]=[CH:6][N+:5]([O-])=[C:4]2[CH2:9][CH2:10][C@@H:11]([CH3:12])[C:3]=12.[C:13]([O:16]C(=O)C)(=[O:15])[CH3:14]>>[C:13]([O:16][CH:9]1[C:4]2[N:5]=[CH:6][N:7]=[C:2]([Cl:1])[C:3]=2[C@H:11]([CH3:12])[CH2:10]1)(=[O:15])[CH3:14]

Participants

3

Reactant 2

HCID 7918Acetic AnhydrideHCID 58111337(R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine 1-oxide

Product 1

HCID 58111335(5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetateYield 70%

Procedure

A solution of (R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine-oxide (1.45 g, 7.85 mmol) in acetic anhydride (20 mL) was heated to 110° C. for 2 hours. After cooling, excess solvent was removed under vacuum. The residue was purified by silica gel chromatography, eluting with hexane/ethyl acetate (3:1) to give (5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetate (1.25 g, 70%). 1H NMR (CDCl3, 400 MHz) δ 8.92 (m, 1H), 6.30-6.03 (m, 1H), 3.60-3.30 (m, 1H), 2.84 (m, 1H), 2.40-2.20 (m, 1H), 2.15 (d, J=6 Hz, 2H), 1.75 (m, 2H), 1.47 (d, J=6.8, 2H), 1.38 (d, J=7.2, 1H). MS (APCI+) [M+H]+ 227.

Workup

  1. temperatureAfter cooling
  2. customexcess solvent was removed under vacuum
  3. customThe residue was purified by silica gel chromatography
  4. washeluting with hexane/ethyl acetate (3:1)

Sources & evidence

ORD record
ord-86d6a6e5d0fd4f739d585597f24ef30f
Source dataset
uspto-grants-2014_09
Patent number
US08846683B2

Reaction notes

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