Carbodiimides chemistry

We investigated the efficiency of NSC expansion on surfaces with EGF-His immobilized in the correct orientation. NSCs were obtained from neurosphere cultures prepared from fetal rat striatum harvested on embryonic day 16. NSCs were cultured for 5 days on EGF-His-immobilized substrates prepared with mixed SAMs of different COOH-thiol contents. Cells adhered and formed network structures at a density that increased with the COOH-thiol content of the surface. As a control, cells were seeded onto surfaces without immobilized EGF-His. This resulted in poor cell adhesion during the entire culture period. In addition, when EGF-His adsorbed to SAMs with 100% COOH-thiol or SAMs with NTA-derivatized COOH that lacked Ni2+ chelation, we observed poor initial cell adhesion, and the cells formed aggregates within 5 days. Interestingly, the substrate used to covalently immobilize EGF-His with the standard carbodiimide chemistry was not a suitable surface for cell adhesion and proliferation. The control experimental results contrasted markedly with results from EGF-His-chelated surfaces. 

Fig. 5.8 Examples of polymers grafted from nanocarbons, (a) An ATRP initiator covalently attached to RGO via nitrene and carbodiimide chemistry was used for the growth of poly(2-(ethyl (phenyl)amino)ethyl-methacrylate). (b) A RAFT chain transfer agent is covalently attached to GO prior to polymerization of vinylcarbozole.

For a review of the reactions in this section, see Bocharov Russ. Chem. Rev. 1965,34. 212-219. For a review of carbodiimide chemistry see Williams Ibrahim Chem. Rev. 1981, 81, 589-636. 

Riedel and coworkers have also uncovered some extremely novel chemistry based on the use of carbodiimide chemistry, including a case where precursor architecture influences phase and compositional development49. The process begins with the very simple synthesis of silylcarbodiimides (equations 15 and 16). In the case where R = Me, the compound is a 16-atom heterocycle (x = 4). For R = H, a polymer is obtained that gives a 65 wt% ceramic yield at 1500 °C and a SiCi.gNi.3 (1000 °C) composition. 

Immobilization of glucose oxidase via carbodiimide chemistry onto a poly(acrylic acid) grafted porous cellulose substrate was performed by Ito, et al. (14). They showed that this system s permeability to insulin in response to a 3600 mg% glucose challenge was 1.7 times greater than the permeability prior to the addition of glucose. 

I would like to acknowledge the contributions of my former co-workers at the Donald S. Gilmore Research Laboratories of the Upjohn Company, especially Dr R.H. Richter and B. Tucker who were involved in the synthesis and cycloaddition reactions of carbodiimides Dr L.M. Alberino who participated in the synthesis of polycarbodiimides Dr K. Onder and Dr WJ. Farrissey, Jr, who played a major role in the development of thermoplastic polyamides based on carbodiimide chemistry Dr H.W. Temme and Dr C.P. Smith, who developed novel polymeric catalysts for the conversion of isocyanates into carbodiimides and A. Odinak, who developed the liquid MDI process. 1 would especially like to acknowledge the encouragement of the late Dr A.A.R. Sayigh. 

I became involved in carbodiimide chemistry in my research work on isocyanates at the former Donald S. Gilmore Research Laboratories of the Upjohn Company in North Haven, CT. Carbodiimides are readily synthesized from isocyanates using a phospholene oxide catalyst. This reaction can be conducted without a solvent, and the byproduct is carbon dioxide. We used this reaction in the manufacture of a liquid version of MDI (4,4 -diisocyanatodiphenylmethane), which today is sold in huge quantities worldwide. By reacting MDI with dicarboxylic acids in a vented extruder we manufactured a family of thermoplastic polyamide elastomers, which are sold today by the Dow Chemical Company. Also, N-sulfonylcarbodiimides were synthesized for the first time in our laboratories. They are the precursors of the antidiabetic sulfonamides, such as Upjohn s Tolbutamide (Orinase). Because of the close relationship of isocyanates with carbodiimides we studied many linear and cyclic carbodiimide reactions, especially their cycloaddition reactions. 

Mikolajczyk M, Kielbasinski P. Recent developments in the carbodiimide chemistry. Tetrahedron 1981 37 233-284. 

The first immunoassay utilizing acridinium esters was described in 1981 (S31, S32). The p-carboxyphenyl ester of 9-carboxy-A -methyl-acridinium bromide (Fig. 24 R = HOOC-(j) A = Br) was coupled by carbodiimide chemistry to the lysine residues of sheep a-fetoprotein (AFP) antibody. Unlabeled antibodies were immobilized onto plastic tubes, and the AFP antigen was assayed in a direct two-site... 

Danion et al. immobilized intact liposomes onto SCLs (Figure 51.11). In the first step, poly-ethylenimine was covalently bounded onto the hydroxyl groups available on the surface of a commercial CL (Hioxifilcon B). Then, NHS-PEG-biotin molecules were bounded onto the surface amine groups by carbodiimide chemistry. NeutrAvidin were bounded onto the PEG-biotin layer. Liposomes containing PEG-biotinylated lipids were docked onto the surface-immobilized NeutrAvidin. Consecutive addition of further NeutrAvidin and liposome layers enabled the fabrication of multilayers. Multilayers of liposomes were also produced by exposing CLs coated with NeutrAvidin to liposome aggregates produced by the addition of free biotin in solution. 

An exception to the definition for pseudo poly(amino acids) as previously established is a polymer synthesized by Chen et al. [31,32], because its backbone is comprised of lysine alternating with an isophthaloyl group and lacks nonamide linkages (Table 12.2). Hydrophobicity of the polymer is increased by conjugating ethanol or hydro-phobic amino acids, such as valine, leucine, and phenylalanine, as protecting groups on the carboxyl terminal of lysine via carbodiimide chemistry. This protected lysine is then copolymerized with isophthaloyl chloride via single-phase polymerization in the presence of a base (Table 12.2) [32]. 

Amide bonds by reaction of amines and active esters (e.g., carbodiimide chemistry)... 

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