Synthesis of 5-Substituted 3-Amino-1H-Pyrazole-4-Carbonitriles as Precursors for Microwave Assisted Regiospecific Syntheses of Pyrazolo[1,5-a]Pyrimidines

Molecules

Fawzia Al-Qalaf²  Faisal Mandani¹  Mervat Mohammed Abdelkhalik² 

[1] Chemical Engineering Technology Department, College of Technological Studies, Public Authority for Applied Education and Training, P. O. Box 42325 Safat, 70654 Kuwait;Applied Science Department, College of Technological Studies, Public Authority for Applied Education and Training, P. O. Box 42325 Safat, 70654 Kuwait; E-mail:

关键词: Oxoalkanonitriles;    2-Aroyl-3-dimethylamino-2-propenenitrile;    Pyrazolo[1;    5-a]pyrimidines;    Solvent-free reactions;    ¹H-¹⁵N HMBC.;   

DOI  :  10.3390/molecules14010078

来源: mdpi

【 摘 要 】

A simple route to 3-oxoalkanonitrile 5, a precursor of the title compounds is described. Reaction of enaminones 2 with hydroxylamine hydrochloride in ethanol yielded aldoximes 3 that were converted readily into 5 in basic medium. This method has been successfully applied with a number of substrates and resulted in excellent yields of the products. Reacting 5 with trichloroacetonitrile afforded 3-amino-2-aroyl-4,4,4-trichloro-2-butenenitriles 6 that condensed with hydrazines to yield 3-amino-1H-pyrazole-4-carbonitrile derivatives 8. Substituted pyrazolo[1,5-a]pyridmidines have been prepared with regioselective condensation reactions of 8 with nonsymmetrical dielectrophiles. The structures of compounds obtained were deduced based on ¹H-NMR, ¹H-¹⁵N HMBC- measurements.

【 授权许可】

CC BY   
© 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.