tailieunhanh - Prakash et al. Organic and Medicinal Chemistry Letters 2011, 1:5

Prakash et al. Organic and Medicinal Chemistry Letters 2011, 1:5 ORIGINAL Open Access Synthesis and antimicrobial evaluation of new 1,4-dihydro-4-pyrazolylpyridines and 4pyrazolylpyridines Om Prakash1, Khalid Hussain2, Ravi Kumar3*, Deepak Wadhwa4, Chetan Sharma5 and Kamal R Aneja5 Abstract 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-2,6dimethyl-4-(3-aryl-1-phenyl-4-pyrazolyl)pyridine-3,5-dicarboxylates (2a-g) and diethyl 2,6-dimethyl-4-(3-aryl-1-phenyl4-pyrazolyl)pyridine-3,5-dicarboxylates (3a-g). Results: Synthesis of a. | Prakash et al. Organic and Medicinal Chemistry Letters 2011 1 5 http content 1 1 5 o Organic and Medicinal Chemistry Letters a SpringerOpen Journal ORIGINAL Open Access Synthesis and antimicrobial evaluation of new 1 4-dihydro-4-pyrazolylpyridines and 4-pyrazolylpyridines dm Pr lz ch1 l H .ilirl I Il ICC3ỈI-I2 R x I ki im3r3 k A .i 1H .a .i4 r-Hod AAA h ir i r. 5 A AAA I Id A A AAA p AaacaIa5 Om rldkdsll Klldlid Hussdin Rdvi Deepdk VVdUMWd Clletdll jhaimd dnd R Anejd Abstract Background Didlkyl 1 4-dihydro-2 6-dimethylpyridine-3 5-dicdrboxyldtes 1 4-DHP hdve now been recognized ds vitdl drugs. Some of these derivdtives such ds dmlodipine felodipine isrddipine etc. hdve been commercidlized. In view of wide rdnge of biologicdl properties dssocidted with 1 4-DHP dnd owing to the biologicdl importance of the oxiddtion step of 1 4-DHP we cdrried out the synthesis dnd dntimicrobidl evdludtion of new diethyl 1 4-dihydro-2 6-dimethyl-4- 3-dryl-1-phenyl-4-pyrdzolyl pyridine-3 5-dicdrboxyldtes 2a-g dnd diethyl 2 6-dimethyl-4- 3-dryl-1-phenyl-4-pyrdzolyl pyridine-3 5-dicdrboxyldtes 3a-g . Results Synthesis of d series of new diethyl 1 4-dihydro-2 6-dimethyl-4- 3-dryl-1-phenyl-4-pyrdzolyl pyridine-3 5-dicdrboxyldtes 2a-g hds been dccomplished by multicomponent cyclocondensdtion redction of ethyl dcetodcetdte 3-dryl-1-phenyl pyrdzole-4-cdrboxdldehyde 1a-g dnd dmmonium dcetdte. The dihydropyridines 2a-g were smoothly converted to new diethyl 2 6-dimethyl-4- 3-dryl-1-phenyl-4-pyrdzolyl pyridine-3 5-dicdrboxyldtes 3a-g using HTIB Hydroxy tosyloxy iodo benzene Koser s redgent ds the oxidizing dgent. The dntimicrobidl studies of the title compounds 2a-g 3a-g dre dlso described. Keywords 1 4-Dihydro-4-pyrdzolylpyridines 4-pyrdzolylpyridines HTIB oxiddtion dntibdcteridl dctivity dntifungdl dctivity Background Dialkyl 1 4-dihydro-2 6-dimethylpyridine-3 5-dicarboxy-lates 1 4-DHP Figure 1 have now been recognized as vital drugs. Some of these .