1,8-Diazabicyclo(5.4.0)undec-7-ene → 2-(6-Methyl-pyridin-2-yl)-pyrazolo[1,5-a]pyridine-3-carboxylic acid ethyl ester

HRID 902004Notes

Reaction equation

HRID 902004 reaction equation
[CH2:1]([O:3][C:4](=[O:14])[C:5]#[C:6][C:7]1[CH:12]=[CH:11][CH:10]=[C:9]([CH3:13])[N:8]=1)[CH3:2].[I-].[NH2:16][N+:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1.C1CCN2C(=NCCC2)CC1>C(#N)C>[CH2:1]([O:3][C:4]([C:5]1[C:6]([C:7]2[CH:12]=[CH:11][CH:10]=[C:9]([CH3:13])[N:8]=2)=[N:16][N:17]2[CH:22]=[CH:21][CH:20]=[CH:19][C:18]=12)=[O:14])[CH3:2]

Participants

5

Reactant 3

HCID 811841,8-Diazabicyclo(5.4.0)undec-7-eneHCID 2733704Pyridinium, 1-amino-, iodide (1:1)HCID 59700610(6-Methyl-pyridin-2-yl)-propynoic acid ethyl ester

Product 1

HCID 597006232-(6-Methyl-pyridin-2-yl)-pyrazolo[1,5-a]pyridine-3-carboxylic acid ethyl esterYield 24.1%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A solution of (6-methyl-pyridin-2-yl)-propynoic acid ethyl ester (0.62 g, 3.3 mmol) and 1-aminopyridinium iodide (0.8 g, 3.6 mmol) in acetonitrile (15 mL) is treated with DBU (0.5 mL, 3.3 mmol) and heated to reflux for 0.5 hours. The reaction is concentrated to a dark solid and purified by silica gel column chromatography (1:1 hexane/ethyl acetate) to afford 0.224 g (24%) of desired product as a yellow solid. MS ES+ m/e 282.2 (M+1). UV (95% EtOH) λmax 275 nm (ε 13005), 234 nm (ε 26550), 225 nm (ε 26057). TOF MS ES+ exact mass calculated for C11H11NO2 (p+1): m/z=282.1243. Found: 282.1244. Anal. Calcd for C16H15N3O2: C, 68.31; H, 5.37; N, 14.94. Found: C, 68.04; H, 5.28; N, 14.65.

Workup

  1. temperatureheated
  2. temperatureto reflux for 0.5 hours
  3. concentrationThe reaction is concentrated to a dark solid
  4. custompurified by silica gel column chromatography (1:1 hexane/ethyl acetate)

Sources & evidence

ORD record
ord-f7d5442fc8d648b6a0ada0deda8319a9
Source dataset
uspto-grants-2008_04
Patent number
US07365066B2

Reaction notes

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