2,2-Dimethyl-1,3-dioxane-4,6-dione → 5-(5-Bromopyridin-2(1H)-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione

HRID 1175630Notes

Reaction equation

HRID 1175630 reaction equation
[Br:1][C:2]1[CH:3]=[N+:4]([O-])[CH:5]=[CH:6][CH:7]=1.[CH3:9][C:10]1([CH3:18])[O:15][C:14](=[O:16])[CH2:13][C:12](=[O:17])[O:11]1>C(OC(=O)C)(=O)C>[Br:1][C:2]1[CH:7]=[CH:6][C:5](=[C:13]2[C:14](=[O:16])[O:15][C:10]([CH3:18])([CH3:9])[O:11][C:12]2=[O:17])[NH:4][CH:3]=1

Participants

4

Reactant 2

HCID 162492,2-Dimethyl-1,3-dioxane-4,6-dioneHCID 142763Pyridine, 3-bromo-, 1-oxide

Product 1

HCID 574434985-(5-Bromopyridin-2(1H)-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dioneYield 20.6%

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent

Procedure

3-Bromopyridine N-oxide (10 g, 57.5 mmol) was slowly added into a solution of 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid, 8.28 g, 57.5 mmol) in acetic anhydride (58 mL) at 0° C. The temperature was allowed to come to room temperature overnight. The mixture was filtered and yellow crystals were washed with small amount of acetic anhydride and dried in vacuo. The residue was triturated with warm chloroform and insoluble residue was filtered off. The chloroform soluble fraction was evaporated and the residue triturated with 5% MeOH in DCM. The solid material was filtered off and the soluble fraction was evaporated to give 3.55 g (20%) of 5-(5-Bromopyridin-2(1H)-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione. 1H NMR (400 MHz, dMSO): δ 1.61 (s, 6H), 1.64 (s, 1H), 8.20-8.23 (dd, 1H), 8.51-8.52 (d, 1H), 8.62-8.65 (d, 1H).

Workup

  1. filtrationThe mixture was filtered
  2. washyellow crystals were washed with small amount of acetic anhydride
  3. customdried in vacuo
  4. customThe residue was triturated with warm chloroform and insoluble residue
  5. filtrationwas filtered off
  6. customThe chloroform soluble fraction was evaporated
  7. customthe residue triturated with 5% MeOH in DCM
  8. filtrationThe solid material was filtered off
  9. customthe soluble fraction was evaporated

Sources & evidence

ORD record
ord-dcb2b5f89f254c4099c680cc1fd9340b
Source dataset
uspto-grants-2010_11
Patent number
US07842324B2

Reaction notes

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