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Upstream product

• 1131-80-2 (E)-3-(N,N-dimethylamino)-1-phenyl-2-propen-1-one 
• 31230-17-8 3-amino-5-methylpyrazole 
• 1201-93-0 1-phenyl-3-dimethylaminoprop-2-enone 
• 98-86-2 acetophenone 

Relevant academic research and scientific papers

3-Formylpyrazolo[1,5- a]pyrimidines as Key Intermediates for the Preparation of Functional Fluorophores

A one-pot route for the regioselective synthesis of 3-formylpyrazolo[1,5-a]pyrimidines 4a-k in good yields through a microwave-assisted process is provided. The synthesis proceeds via a cyclocondensation reaction between β-enaminones 1 with NH-3-aminopyrazoles 2, followed by formylation with an iminium salt moiety (Vilsmeyer-Haack reagent). These N-heteroaryl aldehydes 4 were successfully used as strategic intermediates for the preparation of novel functional fluorophores with yields up to 98%. The structures of the products obtained and regioselectivity of the reactions were determined on the basis of NMR measurements and X-ray diffraction analysis. Since pyrazolo[1,5-a]pyrimidines (PPs) 3 have shown an important fluorescence, photophysical properties of four 2-methylderivatives substituted at position 7 with different acceptor (A) or donor (D) groups were investigated. The compounds evaluated exhibited large Stokes shift in different solvents, but only the substituted p-methoxyphenyl (4-An) showed a strong fluorescence intensity with quantum yields up to 44% due to its greater ICT. Therefore, hybrid systems based on pyrazolo[1,5-a]pyrimidines could be used as fluorescent probes to detect biologically or environmentally relevant species.

Simple access toward 3-halo- and 3-nitro-pyrazolo[1,5-a] pyrimidines through a one-pot sequence

Herein, a regioselective, time-efficient and one-pot route for the synthesis of diversely substituted 3-halo- and 3-nitropyrazolo[1,5-a]pyrimidines in good to excellent yields through a microwave-assisted process is provided. The reaction features a sequential cyclocondensation reaction of β-enaminones with NH-5-aminopyrazoles, followed by a regioselective electrophilic substitution with easily available electrophilic reagents. This methodology is distinguished by its short reaction times, high-yield, operational simplicity, broad substrate scope and pot-economy. Furthermore, these 3-functionalized heterocycles have been successfully used in the synthesis of 3-alkynyl and 3-aminopyrazolo[1,5-a]pyrimidines in yields up to 92%.

Mg-Al hydrotalcites as efficient catalysts for aza-Michael addition reaction: A green protocol

Mg-Al hydrotalcite was synthesized by a co-precipitation method. We have studied the effect of calcination temperature and hydration of the calcined phases on their catalytic activity for the synthesis of pyrazolo[1,5-a] pyrimidine derivatives (aza-Michae

Studies with Heteroaromatic Amines: The Reaction of Some Heteroaromatic Amines with 1-Substituted 3-Dimethylaminopropanones. Enaminones and Cinnamonitriles

Whereas 5-amino-3-methylpyrrazole (3a) reacts with 1-phenyl-3-dimethylaminopropan-1-one hydrochloride (1a), 1-(2-naphthyl)-3-dimethylaminopropan-1-one hydrochloride (1b) and with 1-(2-thienyl)-3-dimethylaminopropan-1-one hydrochloride (1c) to yield the pyrazolopyridine derivatives (5b-d), the 5-amino-3-phenylpyrazole (3b) reacts with (1a) to yield the dihydropyrazolopyrimidine derivative (9).The reaction of 1,3-diphenylpyrazole-5-amine (3c) with (1a) gives the pyrazolopyridine (5e). 2-Aminobenzimidazole reacts with (1a) to yield the dihydrobenzimidazopyrimidine derivative (11).The reaction of 5-amino-3-methylisoxazole (13a) with (1a) gives only the 3-amino-heteroarylpropanone (13b).The reaction of the enaminoketones (2a-c) with (3a,b; 10a) gives azolopyrimidines while the reaction of these enones with (13a, 10b) gives only the alkylamino derivatives (18, 20).The structures of products obtained in this study are confirmed by 1H nmr, 13C nmr and NOE measurements.