Sodium Carbonate → 5-Chloro-2-(4-methylphenyl)pyridine

HRID 882808Notes

Reaction equation

HRID 882808 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([Cl:8])=[CH:4][N:3]=1.B(O)(O)[C:10]1[CH:11]=[CH:12][C:13]([CH3:16])=[CH:14][CH:15]=1.C([O-])([O-])=O.[Na+].[Na+]>C1(C)C=CC=CC=1.CCO.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[Cl:8][C:5]1[CH:6]=[CH:7][C:2]([C:10]2[CH:15]=[CH:14][C:13]([CH3:16])=[CH:12][CH:11]=2)=[N:3][CH:4]=1

Participants

6

Reactant 3

HCID 10340Sodium CarbonateHCID 79799Tolylboronic acidHCID 8170982-Bromo-5-chloropyridine

Product 1

HCID 671210225-Chloro-2-(4-methylphenyl)pyridine

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 21863594Toluene ethanolSolvent

Conditions

Temperature
90 °C

Procedure

Bromine (18.0 ml, 353.7 mmol) is slowly added to a soln. of 2-amino-5-chloropyridine (15.0 g, 116.7 mmol) in 47% aq. HBr (75.0 ml) at −10° C. An aq. soln. of NaNO2 (28.1 g, 407.3 mmol) is slowly added. The mixture is stirred for 1 h at −10 to −5° C., then for 1 h at 5° C. The mixture is neutralised with 5M aq. NaOH soln. maintaining the temperature below 25° C. The precipitate is filtered and recrystallized from pentane to give 2-bromo-5-chloropyridine. 2-Bromo-5-chloropyridine (5.0 g, 26.0 mmol), p-tolylboronic acid (4.0 g, 29.4 mmol) and tetrakis(triphenylphosphine)palladium (1.44 g, 1.2 mmol) are dissolved in toluene:EtOH 9:1 (1375 ml). A 2M aq. Na2CO3 soln. (62.5 ml) is added to the reaction mixture. The mixture is stirred at 90° C. for 24 h, cooled to rt and filtered over celite. The toluene layer is separated and washed with brine. The aq. layers are extracted with AcOEt. The combined organic extracts are dried over MgSO4 and filtered. The filtrate is evaporated to give a brown solid which is purified by FC (silica gel, eluent toluene) to give 5-chloro-2-p-tolyl-pyridine. (R)-3-Quinuclidinol (2.97 g, 23.4 mmol) is added to a suspension of NaH (0.96 g of a 60% dispersion in mineral oil, 22.8 mmol) in DMF (90 ml). The mixture is stirred for 1 h at rt. 5-Chloro-2-p-tolyl-pyridine (4.00 g, 19.6 mmol) is added and the mixture is heated for 135 h at 135° C. The reaction mixture is diluted with toluene and washed with 1 M aq. NaOH soln. and brine. The aq. layers are re-extracted with toluene (3×). The combined organic extracts are dried over MgSO4 and filtered. The filtrate is evaporated to give a brown oil which is purified by FC (silica gel, eluents: AcOEt, then AcOEt/MeOH/NEt3 87:10:3) and recrystallized from CH3CN to give (R)-3-(6-p-tolyl-pyridin-3-yloxy)-1-aza-bicyclo[2.2.2]octane; mp ° C.: 110-112; [α]Drt=+21.2° (0.50, MeOH), M+H+ 295.2.

Workup

  1. addition(62.5 ml) is added to the reaction mixture
  2. temperaturecooled to rt
  3. filtrationfiltered over celite
  4. customThe toluene layer is separated
  5. washwashed with brine
  6. extractionThe aq. layers are extracted with AcOEt
  7. dry with materialThe combined organic extracts are dried over MgSO4
  8. filtrationfiltered
  9. customThe filtrate is evaporated
  10. customto give a brown solid which
  11. customis purified by FC (silica gel, eluent toluene)

Sources & evidence

ORD record
ord-42beda4d36a64af999ab2c95093fe19f
Source dataset
uspto-grants-2012_08
Patent number
US08236803B2

Reaction notes

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