Novel synthesis of new 5,7-disubstituted-2-alkyl/arylamino-4H-pyrazolo[4,5-e][1,3,4]thiadiazines and 4,6-disubstituted-3-amino/anilino-2-alkyl/aryliminopyrazolo[3,4-d]thiazolines was written by Chande, Madhukar S.;Joshi, Rajesh D.. And the article was included in Indian Journal of Chemistry in 1995.Recommanded Product: 51395-52-9 This article mentions the following:
The title compounds have been prepared by reaction of substituted 4-bromopyrazolin-5-ones with thiosemicarbazides. An alternate unambiguous synthesis of pyrazolo[3,4-d]thiazolines has been described. In the experiment, the researchers used many compounds, for example, 4-Bromo-3-methyl-1H-pyrazol-5(4H)-one (cas: 51395-52-9Recommanded Product: 51395-52-9).
4-Bromo-3-methyl-1H-pyrazol-5(4H)-one (cas: 51395-52-9) belongs to pyrazole derivatives. Pyrazole has two ring nitrogen atoms in which N1 is pyrrolic and N2 is pyridine-like. The N1 nitrogen is not reactive but is deprotonated in the presence of a base-forming anion. 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.Recommanded Product: 51395-52-9
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics