lH-Pyrazolo[3,4b]pyridine-3-carboxylic Acid.
KMnO4ZNaOHZH2O
reflux, 2 h
Sodium hydroxide (35 g, 0.88 mol) was dissolved in water (800 mL), then 3- methyl-lH-pyrazolo[3,4b]pyridine (16 g, 0.12 mol) was added to a solution of sodium hydroxide and stirred at room temperature for 10 minutes. The reaction mixture was heated to 80 0C. Under good stirring potassium permanganate solution (68.5 g, 0.433 mol OfKMnO4 in 300 mL water) was slowly added dropwise over a period of 2 h, keeping the oil bath temperature at 100 0C. After completing the addition of potassium permanganate, the reaction mixture was further heated for 1 hr. The progress of the reaction was monitored by TLC. The reaction mixture was cooled to 70-80 0C and the byproduct manganese dioxide was filtered off. The manganese dioxide cake was washed with hot water. The main filtrate and the washings were combined and acidified to pH 2 with concentrated sulfuric acid. The water was then distilled off under reduced pressure using a rotary evaporator. The yellow solid obtained was a mixture of the desired IH- pyrazolo[3,4b]pyridine-3-carboxylic acid, sodium sulfate and potassium sulfate (95 g). This mixture of solids was taken without purification to the next step. A small sample was purified by column chromatography for analytical purposes to afford white crystals mp 175-176 0C.
1H NMR (CDCl3) 8.28 (dd, J = 4.9 and 1.6 Hz, 1 H), 7.82 (dd, J = 7.5 and 1.6 Hz, 1 H), 7.39 (dd J = 7.5 and 4.9 Hz, 1 H).
MS 9FAB) m/z: 147 (M+ + 1)
DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO …..FOR BLOG HOME CLICK HERE
LIONEL MY SON
///////////
सुकून उतना ही देना प्रभू, जितने से जिंदगी चल जाये। औकात बस इतनी देना, कि औरों का भला हो जाये।
DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO …..FOR BLOG HOME CLICK HERE
Join me on twitter
amcrasto@gmail.comLIONEL MY SON
He was only in first standard in school when I was hit by a deadly one in a million spine stroke called acute transverse mylitis, it made me 90% paralysed and bound to a wheel chair, Now I keep him as my source of inspiration and helping millions, thanks to millions of my readers who keep me going and help me to keep my son happy
सुकून उतना ही देना प्रभू, जितने से
जिंदगी चल जाये।
औकात बस इतनी देना,
कि औरों का भला हो जाये।
