Original
Synthesis and antimicrobial evaluation of new 1,4-dihydro-4-pyrazolylpyridines and 4-pyrazolylpyridines
1 Institute of Pharmaceutical Sciences, Kurukshetra University, Kurukshetra 136 119, India
2 Department of Chemistry, Guru Nanak Khalsa College, Yamunanagar 135001, India
3 Department of Chemistry, Dyal Singh College, Karnal 132 001, India
4 Department of Chemistry, Kurukshetra University, Kurukshetra 136 119, India
5 Department of Microbiology, Kurukshetra University, Kurukshetra 136 119, India
Organic and Medicinal Chemistry Letters 2011, 1:5 doi:10.1186/2191-2858-1-5
Published: 3 August 2011Abstract
Background
Dialkyl 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylates (1,4-DHP) have now been recognized as vital drugs. Some of these derivatives such as amlodipine, felodipine, isradipine, etc. have been commercialized. In view of wide range of biological properties associated with 1,4-DHP and owing to the biological importance of the oxidation step of 1,4-DHP, we carried out the synthesis and antimicrobial evaluation of new diethyl 1,4-dihydro-2,6-dimethyl-4-(3-aryl-1-phenyl-4-pyrazolyl)pyridine-3,5-dicarboxylates (2a-g) and diethyl 2,6-dimethyl-4-(3-aryl-1-phenyl-4-pyrazolyl)pyridine-3,5-dicarboxylates (3a-g).
Results
Synthesis of a series of new diethyl 1,4-dihydro-2,6-dimethyl-4-(3-aryl-1-phenyl-4-pyrazolyl)pyridine-3,5-dicarboxylates (2a-g) has been accomplished by multicomponent cyclocondensation reaction of ethyl acetoacetate, 3-aryl-1-phenyl pyrazole-4-carboxaldehyde (1a-g) and ammonium acetate. The dihydropyridines 2a-g were smoothly converted to new diethyl 2,6-dimethyl-4-(3-aryl-1-phenyl-4-pyrazolyl)pyridine-3,5-dicarboxylates (3a-g) using HTIB ([Hydroxy (tosyloxy)iodo]benzene, Koser's reagent) as the oxidizing agent. The antimicrobial studies of the title compounds, 2a-g & 3a-g, are also described.
