2,4,6-Trimethylpyridine → HCID 178435492, compound

HRID 1741246Notes

Reaction equation

HRID 1741246 reaction equation
[CH3:1][CH2:2][C:3]1[C:21]2=[N:22][C:5](=[CH:6][C:7]3[NH:11][C:10]([CH:12]=[C:13]4[CH:34]([CH3:35])[CH:33]([CH2:36][CH2:37][C:38]([O:40][CH3:41])=[O:39])[C:15]([C:16]5[CH:27](C(OC)=O)[C:25](=[O:26])[C:24]6[C:17]=5[NH:18][C:19]([C:23]=6[CH3:32])=[CH:20]2)=[N:14]4)=[C:9]([CH3:42])[C:8]=3[CH:43]=[CH2:44])[C:4]=1[CH3:45].N1C(C)=CC(C)=CC=1C>>[CH3:1][CH2:2][C:3]1[C:21]2=[N:22][C:5](=[CH:6][C:7]3[NH:11][C:10]([CH:12]=[C:13]4[C@@H:34]([CH3:35])[C@H:33]([CH2:36][CH2:37][C:38]([O:40][CH3:41])=[O:39])[C:15]([C:16]5[CH2:27][C:25](=[O:26])[C:24]6[C:17]=5[NH:18][C:19]([C:23]=6[CH3:32])=[CH:20]2)=[N:14]4)=[C:9]([CH3:42])[C:8]=3[CH:43]=[CH2:44])[C:4]=1[CH3:45]

Participants

3

Reactant 2

HCID 79532,4,6-TrimethylpyridineHCID 178435494HCID 178435494, compound

Product 1

HCID 178435492HCID 178435492, compoundYield 23.8%

Procedure

Methyl pheophorbide-a (15.8 g, 26.0 mmol) was added to commercially available 2,4,6-collidine (1.5 L, Aldrich), and the mixture was heated to reflux with stirring. After 30 hours of reflux, the reaction was still incomplete by TLC and HPLC and a heavy baseline was observed. The solution was cooled to room temperature and solvent removed under reduced pressure. The residue was first precipitated twice from methylene chloride/methanol, then purified on a silica gel column with 10% ethyl acetate/methylene chloride. TLC of the desired fraction showed presence of methyl pheophorbide and a heavy baseline. After evaporating off the solvent, the residue was dissolved in 2,4,6-collidine (500 mL) and heated to reflux again. After 2 days of reflux, TLC of the reaction solution still showed the presence of methyl pheophorbide. The reaction solution was evaporated to dryness and the residue was purified on a silica gel column. The desired fraction was evaporated to dryness and the residue was redissolved in methylene chloride, precipitated twice with methanol, and finally purified on a silica gel flash column to give 3.4 g of methyl pyropheophorbide-a.

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux
  3. temperatureAfter 30 hours of reflux
  4. customsolvent removed under reduced pressure
  5. customThe residue was first precipitated twice from methylene chloride/methanol
  6. custompurified on a silica gel column with 10% ethyl acetate/methylene chloride
  7. customAfter evaporating off the solvent
  8. dissolutionthe residue was dissolved in 2,4,6-collidine (500 mL)
  9. temperatureheated
  10. temperatureto reflux again
  11. temperatureAfter 2 days of reflux
  12. customThe reaction solution was evaporated to dryness
  13. customthe residue was purified on a silica gel column
  14. customThe desired fraction was evaporated to dryness
  15. dissolutionthe residue was redissolved in methylene chloride
  16. customprecipitated twice with methanol
  17. customfinally purified on a silica gel flash column

Sources & evidence

ORD record
ord-2f4868fcec1a4265b83017be842b4f95
Source dataset
uspto-grants-1999_10
Patent number
US05973141

Reaction notes

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