Diethyl Ether → 2-(2-Phenylethynyl)pyridine

HRID 857816Notes

Reaction equation

HRID 857816 reaction equation
[C:1]1([C:7]#[C:8][C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][N:10]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C1(C)C=C(C)C=C(C)C=1S(O[NH2:27])(=O)=O.C(OCC)C.C([O-])([O-])=O.[K+].[K+]>ClCCl.O>[C:1]1([C:7]2[CH:8]=[C:9]3[CH:14]=[CH:13][CH:12]=[CH:11][N:10]3[N:27]=2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1.[C:1]1([C:7]#[C:8][C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][N:10]=2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

8

Reactant 4

HCID 3283Diethyl EtherHCID 11430Potassium CarbonateHCID 831752-(2-Phenylethynyl)pyridineHCID 11830845O-(2,4,6-Trimethylbenzenesulfonyl)hydroxylamine

Product 2

HCID 831752-(2-Phenylethynyl)pyridineHCID 156203422-Phenylpyrazolo[1,5-a]pyridine

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent2×

Procedure

2-Phenylpyrazolo[1,5-a]pyridine was prepared by the following procedure. A solution of 2-(phenylethynyl)pyridine (3.2 g, 0.018 mol) in dichloromethane (20 mL) was cooled to 0° C. in an ice bath. A solution of O-mesitylenesulfonylhydroxylamine in dichloromethane was added dropwise, keeping the temperature below 5° C. The mixture was stirred for 30 minutes, then ethyl ether was added to precipitate a solid (5–7 g). The solid was filtered off, washed with ethyl ether and dried. The solid was re-dissolved in DMF and solid K2CO3 (4.5 g, 0.033 mol) was added in small portions. After stirring 2 h, water (100 mL) was added to the mixture, followed by extraction with dichloromethane. The organics were dried over magnesium sulfate, filtered, and evaporated to an orange oil (2.3 g). Chromatography on silica with dichloromethane eluent yielded the 2-(phenylethynyl)pyridine in 83% yield, mp 110° C. 1H NMR and mass spectra analysis confirmed the structure.

Workup

  1. customthe temperature below 5° C
  2. customto precipitate a solid (5–7 g)
  3. filtrationThe solid was filtered off
  4. washwashed with ethyl ether
  5. customdried
  6. dissolutionThe solid was re-dissolved in DMF
  7. stirringAfter stirring 2 h
  8. extractionfollowed by extraction with dichloromethane
  9. dry with materialThe organics were dried over magnesium sulfate
  10. filtrationfiltered
  11. customevaporated to an orange oil (2.3 g)

Sources & evidence

ORD record
ord-2e1cec987f6d4805aaf7fb95d85e2adc
Source dataset
uspto-grants-2006_12
Patent number
US07147937B2

Reaction notes

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