A novel synthetic approach towards pyrazole-4-carboxamides using N-(3-(dimethylamino)-2-formylacryloyl)formamide

Abstract  

A novel synthesis of pyrazole-4-carboxamides is reported. The reaction of N-(3-(dimethylamino)-2-formylacryloyl)formamide, an intermediate obtained by Vilsmeier–Haack formylation of acetonitrile, with hydrazine hydrate or monosubstituted hydrazines provides such compounds in good yields. This method has advantages over other methods for construction of such ring systems previously described in the literature.     

Arylbenzo[<Emphasis Type="Italic">h</Emphasis>][1, 6]naphthyridine Derivatives: Synthesis and Photophysical Properties

Suzuki-Miyaura cross coupling was successfully used for C5-arylation in 4-amino-2-chloroquinoline-3-carbaldehyde using arylbornic acid and tetrakistriphenylphosphine palladium catalyst in water. Friedländer condensation reaction on 4-amino-2-chloro/2-arylquinoline-3-carbaldehyde and aromatic ketones gave novel aryl and diarylbenzo[h] [1, 6]naphthyridines in good yields. Fluorescence quantum yields were increased by introducing C2 and C5 π donor aryl benzo[h][1, 6]naphthyridines derivatives.

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Figure Synthesis of Fluorescent Arylbenzo[h][1, 6]naphthyridine

     

New Chromogenic Spray Reagent for Detection and Identification of Carbosulfan

JPC – Journal of Planar Chromatography – Modern TLC - A new chromogenic spray reagent has been used for detection and identification of carbosulfan in HPTLC. Alkaline hydrolysis of...     

Syntheses of New Unsymmetrical 2,5‐Disubstituted‐1,3,4‐oxadiazoles and 1,2,4‐Triazolo[3,4‐b]‐1,3,4‐thiadiazoles Bearing Thieno[2,3‐c]pyrazolo Moiety

New series of (thieno[2,3‐c]pyrazolo‐5‐yl)‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazoles 10a , 10b , 10c and (thieno[2,3‐c]pyrazol‐5‐yl)‐1,3,4‐oxadiazol‐3(2H)‐yl)ethanones 6a , 6b , 6c has been synthesized from thieno[2,3‐c]pyrazole‐5‐carbohydrazide 3 by multistep reaction sequence. (5‐Aryl‐1,3,4‐oxadiazol‐2‐yl)‐1H‐thieno[2,3‐c]pyrazoles 4a , 4b , 4c were also synthesized from thieno[2,3‐c]pyrazole‐5‐carbohydrazide 3 by cyclization with various aromatic carboxylic acids. The hydrazide 3 was obtained by reaction of thieno[2,3‐c]pyrazole‐5‐carboxylate 2 with hydrazine hydrate in good yield, and compound 2 was obtained by the reaction of 5‐chloro‐3‐methyl‐1‐phenyl‐1H‐pyrazole‐4‐carbaldehyde 1 and 2‐ethyl thioglycolate in presence of sodium alcoholate in good yield.