Synthesis of Cationic Antimicrobial β2,2-Amino Acid Derivatives with Potential for Oral Administration
摘要:
We have prepared a series of highly potent achiral cationic beta(2,2)-amino acid derivatives that fulfill the Lipinski's rule of five and that contain the basic structural requirements of short cationic antimicrobial peptides. Highest antimicrobial potency was observed for one of the smallest beta(2,2)-amino acid derivatives (M-w 423.6) exhibiting a MIC of 3.8 mu M against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and Staphylococcus aureus, and 7.7 mu M against Escherichia coli. The beta(2,2)-amino acid derivatives were shown to have similar absorption properties as several commercially available drugs, and the results implied a resembling membrane disrupting mechanism of action as reported for much larger cationic antimicrobial peptides. By their high potency, nontoxicity, absorption properties, and ease of synthesis, the beta(2,2)-amino acid derivatives demonstrate a way to modify a vastly investigated class of cationic antimicrobial peptides into small drug-like molecules with high commercial potential.
α-proton in the cyclization process. The acidity dependence of the cyclization reactions and 13C NMR studies of a model compound, methyl cyanoacetate, in various acidic media were consistent with the involvement of the O,N-diprotonated dication of methyl cyanoacetate, a distonic dication, in strong acid, and this is considered to be the de facto electrophile in the present cyclization reaction of arylcyanopropionates
我们介绍了芳基氰基丙酸酯的超强酸催化的分子内环化反应,以中等至高收率得到环化的五元和六元β-烯胺酯。质子化的腈与芳族碳原子的已知分子内闭环反应限于6元情况。有趣的是,观察到的氰基官能度反应性的显著协同增加,和氰基的氮原子被转化成氨基,当酯基存在于一个孪位的布置。氘交换实验排除了α-质子去质子化在环化过程中的参与。环化反应和13的酸度依赖性在各种酸性介质中对模型化合物氰基乙酸甲酯的13 C NMR研究与强酸中氰基乙酸甲酯的O,N-二质子化指示剂(二元体指示剂)在强酸中的参与一致,这被认为是事实上的亲电子试剂。在本发明的芳基氰基丙酸酯的环化反应中。
Reductive alkylation of active methylene compounds with carbonyl derivatives, calcium hydride and a heterogeneous catalyst
A one-pot two-step reaction (Knoevenagel condensation – reduction of the double bond) has been developed using calcium hydride as a reductant in the presence of a supported noble metal catalyst. The reaction between carbonyl compounds and active methylene compounds such as methylcyanoacetate, 1,3-dimethylbarbituric acid, dimedone and the more challenging dimethylmalonate, affords the corresponding
Atom- and Step-Economical Preparation of Reduced Knoevenagel Adducts Using CO as a Deoxygenative Agent
作者:Pavel N. Kolesnikov、Dmitry L. Usanov、Evgeniya A. Barablina、Victor I. Maleev、Denis Chusov
DOI:10.1021/ol502424t
日期:2014.10.3
A highly efficient one-step Rh-catalyzed preparation of reduced Knoevenagel adducts of various aldehydes and ketones with active methylene compounds has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide as a deoxygenative agent. The use of malonic acid or cyanoacetamide enabled efficient formal deoxygenative addition of methyl acetate or acetonitrile to aldehydes. The developed methodology was applied to the synthesis of the precursors of biomedically important compounds.