1-N-Boc-4-Piperidinecarboxylic acid methyl ester → 4-(6,7-Dimethoxy-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester

HRID 657184Notes

Reaction equation

HRID 657184 reaction equation
[CH3:1][O:2][C:3]([CH:5]1[CH2:10][CH2:9][N:8]([C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])[CH2:7][CH2:6]1)=[O:4].Cl[C:19]1[C:28]2[C:23](=[CH:24][C:25]([O:31][CH3:32])=[C:26]([O:29][CH3:30])[CH:27]=2)[N:22]=[CH:21][N:20]=1.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.C1COCC1>>[CH3:1][O:2][C:3]([C:5]1([C:19]2[C:28]3[C:23](=[CH:24][C:25]([O:31][CH3:32])=[C:26]([O:29][CH3:30])[CH:27]=3)[N:22]=[CH:21][N:20]=2)[CH2:6][CH2:7][N:8]([C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])[CH2:9][CH2:10]1)=[O:4]

Participants

4

Reactant 3

HCID 3928701-N-Boc-4-Piperidinecarboxylic acid methyl esterHCID 27693644-Chloro-6,7-dimethoxyquinazolineHCID 23714775LiHMDS tetrahydrofuran2×

Product 1

HCID 587707804-(6,7-Dimethoxy-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester

Procedure

To a mixture of piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (17.1 g, 70.5 mmol), as prepared in the previous step, and 4-chloro-6,7-dimethoxyquinazoline (15.0 g, 67.0 mmol) (Oakwood Products, Inc.) immersed in a −78° C. bath was added 1.08 M LiHMDS/THF (71 mL, 77 mmol) in ˜20 mL portions under argon via syringe along the sides of the flask (to allow cooling of the hindered base before reaction with the ester). Following completion of LiHMDS/THF addition, the reaction was allowed to sit in the −78° C. bath for 2-3 min before removing the cold bath and allowing the mixture to stir with gradual warming to rt. After 18 h stirring at rt, and an additional 2 d sitting at rt, the mixture was quenched with 0.5 M NaH2PO4 (150 mL) and extracted with DCM (1×150 mL and 1×100 mL). The organic layers were combined, dried (Na2SO4), and concentrated under reduced pressure to provide the crude title compound as a translucent yellow oil that was used in the next step without further purification (33 g, “114%” crude yield). A small sample was purified by flash chromatography (1:1 hex/EtOAc) for characterization. 1H-NMR (400 MHz, CDCl3) δ 9.11 (s, 1H), 7.34 (s, 1H), 7.29 (s, 1H), 4.05 (s, 3H), 3.96 (s, 3H), 3.76-3.67 (m, 2H), 3.62-3.49 (m, 2H), 3.61 (s, 3H), 2.50-2.36 (br s, 4H), 1.46 (s, 9H). LC/MS (ESI): calcd mass 431.2, found 432.2 (MH)+.

Workup

  1. customimmersed in a −78° C.
  2. custombefore removing the cold bath
  3. stirringAfter 18 h stirring at rt
  4. customan additional 2 d
  5. customsitting at rt
  6. customthe mixture was quenched with 0.5 M NaH2PO4 (150 mL)
  7. extractionextracted with DCM (1×150 mL and 1×100 mL)
  8. dry with materialdried (Na2SO4)
  9. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-7b060df6e18d4656828817a352184e57
Source dataset
uspto-grants-2011_12
Patent number
US08071768B2

Reaction notes

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