The title (E)-(3-nitrophenyl)-1-(pyrazin-2-yl)prop-2-en-1-ones were prepared by the Claisen- Schmidt condensation of acetylpyrazines and 2-nitro-, 3-nitro- and 4-nitrobenzaldehyde in pyridine using diethylamine as the catalyst. The compounds were bioassayed for in vitro antifungal, antimycobacterial and photosynthesis-inhibiting activity. The high potency of (E)-1-(5-tert-butylpyrazin-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one againstMycobacterium tuberculosis(MIC 0.78 μg/ml) and moderate activities of several compounds againstTrichophyton mentagrophytesandCandidaspp. do not support the assumption that phenolic groups are essential for antimycobacterial and antifungal activity of chalcones and their analogues. In fact, the nitro-substituted compounds were superior to the previously described hydroxylated congeners with antimycobacterial activity (MIC ≥ 12.5 μg/ml). The compounds also reduced chlorophyll content in green algaChlorella vulgaris, and some of them inhibited photosynthetic electron transport in spinach chloroplasts as well. The photosynthesis-inhibiting activity of nitro derivatives was lower than that of the corresponding hydroxylated analogues.
标题:通过使用2-硝基、3-硝基和4-硝基苯甲醛与乙酰吡嗪在吡啶中以二乙胺为催化剂进行克莱森-施密特缩合反应合成了(E)-(3-硝基苯基)-1-(吡唑-2-基)丙烯酮。这些化合物进行了体外抗真菌、抗结核分枝杆菌和抑制光合作用的生物测定。其中(E)-1-(5-叔丁基吡唑-2-基)-3-(4-硝基苯基)丙烯酮对结核分枝杆菌具有高效抑制作用(最小抑菌浓度为0.78μg/ml),而一些化合物对白色念珠菌和癣菌具有中等活性。这表明酚类基团并非chalcones及其类似物的抗真菌和抗结核分枝杆菌活性所必需。实际上,硝基取代的化合物优于具有抗结核分枝杆菌活性的羟基化同系物(最小抑菌浓度≥12.5μg/ml)。这些化合物还可以减少绿藻Chlorella vulgaris的叶绿素含量,并且其中一些化合物还能抑制菠菜叶绿体中的光合电子传递。硝基衍生物的光合作用抑制活性低于相应的羟基化类似物。