Hydrochloric Acid → Imidazo(1,5-a)pyridine

HRID 2206442Notes

Reaction equation

HRID 2206442 reaction equation
Cl.[N:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[CH:8]=O.C=O.CO.[C:14](#[N:16])C>C(O)C.C(Cl)Cl>[CH:8]1[N:16]=[CH:14][N:2]2[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=12

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 712FormaldehydeHCID 887MethanolHCID 6342AcetonitrileHCID 142732-Pyridinecarboxaldehyde

Product 1

HCID 274090Imidazo(1,5-a)pyridine

Reagents, catalysts & solvents 2

HCID 702EthanolSolvent2×HCID 6344DichloromethaneSolvent

Procedure

Imidazo[1,5-a]pyridine fluorophores were prepared by adding 1 equivalent (equiv) of 3 M hydrochloric acid in ethanol (an additional equivalent of acid was used in reactions with basic substrates) and picolinaldehyde or other 2-acylpyridine to 1 equiv of a 0.5 M solution of 1 equiv of primary amine in dry ethanol or acetonitrile and 1.5 equiv of formalin. The reaction was stirred at room temperature for the specified period of time (i.e., from about 15 min to about 12 hours) and monitored by analytical thin layer chromatography (TLC) (10% methanol in DCM) for the appearance of a blue fluorescent product spot by UV light. Crude reaction mixtures were concentrated in vacuo (˜15 Torr) and dried under high vacuum at 0.2 Torr (for from 2 to 12 hours).

Workup

  1. customCrude reaction mixtures
  2. concentrationwere concentrated in vacuo (˜15 Torr)
  3. customdried under high vacuum at 0.2 Torr (for from 2 to 12 hours)

Sources & evidence

ORD record
ord-5cd34d59a06b42d38a2538ebb26b806c
Source dataset
uspto-grants-2016_06
Patent number
US09371448B2

Reaction notes

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