Microwave synthesis and antifungal evaluations of some chalcones and their derived diaryl-cyclohexenones.
Microwave irradiation (MWI) of acetophenones and substituted benzaldehydes in water resulted in a "green-chemistry" procedure for the preparation of chalcones (1-14), through base catalyzed Claisen-Schmidt condensation reaction, in good yields. Further 3,5-diaryl-6-carbethoxy-2-cyclohexen-1-ones (1a-14a) were prepared through base catalyzed cyclocondensation of above chalcones with ethylacetoacetate using MWI as the energy source and silica as support. Out of fourteen cyclohexenones, ten (1a, 4a, 5a, 6a, 7a, 9a, 10a, 11a, 12a and 13a) are reported for the first time in literature. The synthesized compounds were characterized using various spectroscopic techniques, viz. ((1)H NMR and IR) and screened for their antifungal activity in vitro against Sclerotium rolfsii and Rhizoctonia solani by poisoned food technique. The compounds tested were found to be active against R. solani whereas against S. rolfsii, moderate activity was observed, as evident from LC(50) values. The most potent compounds against R. solani were 1-(4-Fluoro-phenyl)-3-phenyl-propenone (13) and 1,3-Diphenyl-propenone (14) having LC(50) values of 2.36 and 2.49 mg L(- 1) respectively (LC(50) of Hexaconazole = 1.12 mg L(- 1)) and against S. rolfsii 3-(4-Fluoro-phenyl)-5-(3-nitro-phenyl)-6-carbethoxy-2-cyclohexen-1-one (12a) was most active having LC(50) value of 285 mg L(- 1)compared to Hexaconazole (LC(50) = 1.27 mg L(- 1)).
Shakil
N A
NA
Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi, India. iamshakil@gmail.com
Singh
Manish K
MK
Kumar
Jitendra
J
Sathiyendiran
M
M
Kumar
Gaurav
G
Singh
Mukesh K
MK
Pandey
Ravi Prakash
RP
Pandey
Alka
A
Parmar
V S
VS
D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001487:Basidiomycota / Q000187:drug effects*; D047188:Chalcones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008872:Microwaves; D013329:Structure-Activity Relationship
D000935:Antifungal Agents; D047188:Chalcones