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An effective route to pyrrolo[1,2-a]pyrazines is described via reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives in the presence of 20 mol%of sulfamic acid. 相似文献
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Hedieh Pilali Shirin Faraji Kamazani Shahram Moradi Setareh Moghimi Mohammad Mahdavi Loghman Firoozpour 《合成通讯》2016,46(6):563-567
A novel three-step sequence toward benzo[e]imidazo[1,2-c][1,2,3]triazine derivatives is investigated. This pathway started from commercially available starting materials afforded 5a–h in good to excellent yields. In this method, we took the advantage of diazonium chemistry, which was followed by intramolecular N-N bond formation in the construction of N-rich cycles. 相似文献
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A simple and efficient synthetic protocol has been developed using a one-pot multicomponent reaction (MCR) involving 2-aminophenols, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate in poly(ethyleneglycol). This protocol was utilized to prepare novel pyrrolo[2,1-c][1,4]benzoxazines in excellent yields. 相似文献
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Etheno-damaged DNA adducts such as 3,N 4-ethenocytosine, N 2,3-ethenoguanine, and 1,N 2-ethenoguanine are associated with carcinogenesis and cell death. These inevitable damages are counteracted by glycosylase enzymes, which cleave damaged nucleobases from DNA. Escherichia coli alkyl purine DNA glycosylase is the enzyme responsible for excising damaged etheno adducts from DNA in humans. In an effort to understand the intrinsic properties of these molecules, we examined gas-phase acidity values and proton affinities (PA) of multiple sites of these molecules as well as equilibrium tautomerization and base pairing properties by quantum mechanical calculations. We also used calculations to compare the acidic and basic properties of these etheno adduct with those of the normal bases—cytosine and guanine nucleobases. We hypothesize that alkyl DNA glycosylase may cleave certain damaged nucleobases as anions and that the active site may take advantage of a nonpolar environment to favor deprotonated cytosine or guanine as a leaving group versus damaged nucleobases. 相似文献