A Review of Surface Functionalized Amine Terminated Dendrimers for Application in Biological and Molecular Sensing

Dendrimers are three dimensional nanosized synthetic molecules that have internal cavities and numerous surface groups. In recent times they have received increased attention in sensing applications. For dendrimers to be used as sensors, they most commonly require functionalization at their surface. This is because the surface is generally the first point of contact between the dendrimer and the outside world, hence surface functionalization serves to selectively home in on the target analyte. Further, sensor signals may be transmitted through surface functionalities e.g. fluorochromic molecules. It is therefore important to document surface functionalization approaches. Dendrimers with amine surface groups have the advantage of being able to be conjugated to other molecules via an amide linkage, which is one of the most fundamental and widespread chemical bonds in nature. In this paper we demonstrate the properties of dendrimers that make them so applicable to sensing. We review several methods for functionalizing dendrimers via an amide linkage, as well as present a review of surface functionalized polyamidoamine, polyamine, and polypeptide dendrimers that have been employed for biological, chemical and molecular sensing.     

Graphene oxide (GO) catalyzed transamidation of aliphatic amides: An efficient metal-free procedure

Transamidation involves direct interconversion of an amide with amine, and represents an alternative to the common method of amide formation from the reaction of carboxylic acid with an amine. While the carboxamides have huge potential in biological systems and polymer industries, their formation from carboxylic acids requires activation by a suitable catalyst. A metal-free transamidation of aliphatic amide with aromatic amine catalyzed by graphene oxide (GO) has been developed and established as a general, synthetically useful and selective procedure. Graphene oxide bearing several carboxylic acids on the edges and having large surface area acts as an efficient and recyclable catalyst for transamidation.     

氟喹诺酮-3-N-酰胺类衍生物的合成与抗肿瘤活性

为扩展氟喹诺酮由抗菌活性向抗肿瘤活性转化的结构修饰策略,利用药效团生物电子等排及其拼合和骨架迁越药物化学分子构建方法,以酰胺基作为氟喹诺酮C-3位羧基的生物电子等排体,氟喹诺酮骨架为酰胺基的功能修饰基,设计合成了氟喹诺酮-3-N-酰胺类目标化合物。其结构经元素分析和光谱数据确证。体外抗肿瘤实验结果表明,目标化合物对Hep-3B细胞和Capan-1细胞的抗增殖活性均显著强于母体环丙沙星的活性,尤其对Hep-3B细胞的抑制活性最强。因此,用酰胺基来替代C-3羧基有利于提高氟喹诺酮的抗肿瘤活性。     

Carbonylation of C−N Bonds in Tertiary Amines Catalyzed by Low‐Valent Iron Catalysts

The first iron catalysts able to promote the formal insertion of CO into the C?N bond of amines are reported. Using low‐valent iron complexes, including K₂[Fe(CO)₄], amides are formed from aromatic and aliphatic amines, in the presence of an iodoalkane promoter. Inorganic Lewis acids, such as AlCl₃ and Nd(OTf)₃, have a positive influence on the catalytic activity of the iron salts, enabling the carbonylation at a low pressure of CO (6 to 8 bars).     

Chemoenzymatic synthesis of β-carboline derivatives using McbA,a new ATP-dependent amide synthetase

McbA was characterized in vitro as a novel amide synthetase in the marinacarbolines A–D biosynthetic pathway, catalyzing amide bond formation between 1-acetyl-3-carboxy-β-carboline (1a) and substituted-β-phenethylamines (1b, 2b, 3b) and tryptamine (4b) in an ATP-dependent manner. Enzyme kinetic analyses highlight β-phenethylamine as the most suitable amine donor. McbA showed broad substrate compatibility with substituted amines; 10 new β-carboline analogues were chemoenzymatically generated.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Synthesis and Herbicidal Activity of O,O-Diethyl N-{4-Methyl-[1,2,3]thiadiazole-5-carbonyl}- 1-amino-1-substitutedbenzyl Phosphonates

Target compounds 3 were synthesized by the condensation of O,O-diethyl α-amino substitutedbenzyl phosphonates 1 and 4-methyl-[1,2,3]thiadiazole-5-carboxylic acid 2 in the presence of dicyclohexylcarbodiimide (DCC) as a dehydration reagent. Their structures were confirmed by spectroscopic data (IR, ¹H NMR, ³¹P NMR, MS) and elemental analysis. The results of a preliminary bioassay (in vitro) indicated that some of the title compounds 3 possessed moderate to good herbicidal activities against dicotyledonous plants (Brassica campestris L) at the concentration of 100 mg/L, and most of these compounds exhibited higher herbicidal activities against dicotyledonous plants (Brassica campestris L) than monocotyledonous plants (Echinochloa crus-galli).

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Conformational analysis of N-aryl-N-(2-azulenyl)acetamides

Aromatic amides bearing 2-azulenyl group on the amide nitrogen were synthesized and their structures were investigated. The π-electron density of the N-aryl group was found to influence the cis-trans conformational preferences of these compounds in solution. X-ray crystallography revealed that the plane of the 2-azulenyl ring has a strong tendency to lie coplanar with the amide plane when the azulene group is located on the same side as the amide oxygen atom.