Nitroolefins. I. A new and convenient access to indolizines and pyrazolo[1,5-a]pyridines using 1-nitro-2-(phenylthio)ethylene was written by Tominaga, Yoshinori;Ichihara, Yuichi;Hosomi, Akira. And the article was included in Heterocycles in 1988.HPLC of Formula: 104468-72-6 The following contents are mentioned in the article:
1-Nitro-2-(phenylthio)ethylene reacts with a variety of N-ylides and N-imines (pyridinium, isoquinolinium, quinolinium, phthalazinium N-ylides and N-imines) in the presence of Et3N to give the corresponding fused pyrrole and pyrazole derivatives [indolizines I (R = H, R1 = CO2Et, CN, R2 = H, Me), pyrrolo[2,1-a]isoquinoline, pyrrolo[2,1-a]phthalazine (II, R = H), pyrazolo[1,5-a]pyridine, pyrazolo[5,1-a]quinoline, and pyrazolo[5,1-a]isoquinoline], along with the corresponding 1-nitropyrrolopyridines and 1-nitropyrazolopyridines, e.g., I and II (R = NO2), resp., in moderate yields. This study involved multiple reactions and reactants, such as 5-Methylpyrazolo[1,5-a]pyridine (cas: 104468-72-6HPLC of Formula: 104468-72-6).
5-Methylpyrazolo[1,5-a]pyridine (cas: 104468-72-6) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. The presence of both electronegative nitrogen atoms in the pyrazole ring reduces the electron density of the C3- and C5-positions leaving electron density of C4-position unaltered. Thus the C4-position is vulnerable to electrophilic attack. The C3 electrophilic-position may undergo deprotonation in the presence of a strong base leading to ring opening.HPLC of Formula: 104468-72-6
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics