Acetic Acid → Borane;2-methylpyridine

HRID 425266Notes

Reaction equation

HRID 425266 reaction equation
[BH3:1].[N:2]1C=CC=CC=1.B.[CH2:9]([C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][N:13]=1)[CH2:10][CH3:11].[CH3:18][C:19]1[CH:20]=N[CH:22]=[CH:23][CH:24]=1.C(C1C=NC=CC=1)C.C(C1C=CN=CC=1)C.[C:41](O)(=O)[CH3:42]>N1C=CC=CC=1>[BH3:1].[N:13]1[CH:14]=[CH:15][CH:16]=[CH:17][C:12]=1[CH3:9].[BH3:1].[CH2:9]([C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][N:13]=1)[CH3:10].[BH3:1].[N:13]1[C:12]([CH3:17])=[CH:9][CH:10]=[CH:11][C:41]=1[CH3:42].[BH3:1].[N:2]1[C:23]([CH3:22])=[CH:24][C:19]([CH3:18])=[CH:20][C:41]=1[CH3:42]

Participants

12

Reactant 7

HCID 176Acetic AcidHCID 6331Borane2×HCID 79703-MethylpyridineHCID 108224-EthylpyridineHCID 108233-EthylpyridineHCID 693202-PropylpyridineHCID 2723995Borane;pyridine

Product 4

HCID 16217944Borane;2-methylpyridineHCID 178419164HCID 178419164, compoundHCID 178419168HCID 178419168, compoundHCID 178419174HCID 178419174, compound

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent2×

Procedure

Pyridine forms an amine borane that is not moisture sensitive and very useful for reductive aminations and reductions in protic media. Pyridine borane is commercially available and often used in acetic acid to increase the reactivity of the borane. Unfortunately, it is thermally unstable and must be kept at temperatures less than 54° C. to avoid decomposition via hydroboration/polymerization processes. Its shelf-life at ambient temperature is only 6 months, Borane complexes of pyridine, 2-n-propylpyridine, 3-methylpyridine, 3-ethylpyridine and 4-ethylpyridine are liquids which violently decompose upon distillation (Mooney E. F. et al., J. Inorg. Nucl. Chem 1968, 30, p. 1439). 2-Picoline borane (mp. 50° C.), 2-ethylpyridine borane (mp, 50-51° C.), 2,6-lutidine borane (mp. 106-107° C.) and 2,4,6-collidine borane (mp. 99-100° C.) have been isolated as solids.

Workup

  1. custommust be kept at temperatures less than 54° C.
  2. customvia hydroboration/polymerization processes
  3. waitIts shelf-life at ambient temperature is only 6 months
  4. distillationupon distillation (Mooney E. F. et al., J. Inorg. Nucl. Chem 1968, 30, p. 1439)

Sources & evidence

ORD record
ord-4d143ad01d254d1b85140b1240a70419
Source dataset
uspto-grants-2012_01
Patent number
US08106200B2

Reaction notes

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