Bonded Derivatives

Polyether. A polymer in which the repeating unit includes a carbon-oxygen bond derived from aldehydes, epoxides, poly alcohols or similar materials (Refs 1 4a). 

These questions can often be answered with the aid of a set of rules regarding the properties of electron-pair bonds derived from the quantum mechanics, and of a semi-quantitative method of treatment of bond eigenfunctions leading to information on the strengths and relative orientation of bonds2). The rules are the following. 

Escudie, Jean, and Ranaivonjatovo, Henri, Doubly Bonded Derivatives of... 

Scheme 8-24 Hydrozirconation of phosphorus-X double bond derivatives...

The application of whole-cells or enzyme-based catalysts was protected in two different bioprocess patents ([56] and [57], respectively). The patent specifies the process [57] involving a sulfur-specific reactant with membrane fragments, an enzyme, or a composition of enzymes having the ability to selectively react with sulfur by cleavage of organic C—S bonds, derived from R. rhodochrous strain ATCC No. 53968 or B. sphaericus strain ATCC No. 53969. 

Figure 1.86 Citraconic anhydride can be used to block amine groups reversibly. The amide bond derivative is unstable to acidic conditions.

Figure 1.104 SFB reacts with primary amines to form amide bond derivatives containing aldehyde groups.

Figure 1.110 The reaction of SANH with an amine-containing molecule results in an amide bond derivative that terminates in a protected hydrazine group. Reaction with an aldehyde-containing molecule results in release of the acetone-protecting group and formation of a stable hydrazone bond.

Figure 1.118 Sulfo-NHS acetate may be used to block amine groups, forming permanent amide bond derivatives.

Figure 5.10 SIAC reacts with an amine-containing compound to yield an amide bond derivative that is reactive toward thiol-containing molecules. Secondary reaction with a sulfhydryl group gives a stable thioether bond.

Figure 5.25 The reaction of sulfo-SAPB with an amine group is done first to form an amide bond derivative through its NHS ester end. Subsequent exposure to UV light causes the phenyl azide group to ring-expand to a highly reactive dehydroazepine, which can couple to nucleophiles, such as amines.

One Cascade Blue derivative is available for creating linkages with amine-containing molecules. The acetyl azide functionality of this reagent reacts with primary amines at ambient temperatures or below to create amide bond derivatives (Lanier and Recktenwald, 1991 Oparka et al.,... 

The NHS ester end of NHS-LC-biotin reacts with amine groups in proteins and other molecules to form stable amide bond derivatives (Figure 11.4). Optimal reaction conditions are at a pH of 7-9, but the higher the pH the greater will be the hydrolysis rate of the ester. Avoid amine-containing buffers which will compete in the acylation reaction. NHS-LC-biotin is insoluble in aqueous reaction conditions and must be solubilized in organic solvent prior to the addition of a small quantity to a buffered reaction. Preparation of concentrated stock solutions may be done in DMF or DMSO. Nonaqueous reactions also may be done with this reagent for the modification of molecules insoluble in water. The molar ratio of NHS-LC-biotin to a... 

NHS-iminobiotin can be used to label amine-containing molecules with an iminobiotin tag, providing reversible-binding potential with avidin or streptavidin. The NHS ester reacts with proteins and other amine-containing molecules to create stable amide bond derivatives (Figure 11.6). An iminobiotinylated molecule then can be used to target and purify other... 

Figure 17.18 The Staudinger ligation reaction uses a modified phosphine derivative containing an electrophilic group that acts as a trap for the nucleophilic nitrogen in the intermediate aza-ylide. The resultant shift yields an amide bond derivative between the phosphine-containing molecule and the azide-containing molecule.

Figure 18.16 NHS-chromogenic-PEG3-biotin reacts with amine groups in proteins or other molecules to form amide bond derivatives.

Figure 20.6 Available amine groups on an antibody molecule may be modified with the NHS ester end of SATA to produce amide bond derivatives containing terminal protected sulfhydryls. The acetylated thiols may be deprotected by treatment with hydroxylamine at alkaline pH. Reaction of the thiolated antibody with a maleimide-activated enzyme results in thioether crosslinks.

Figure 25.10 PEG-amine compounds may be reacted with this heterobifunctional crosslinker to form amide bond derivatives terminating in maleimide groups. This results in a homobifunctional reagent capable of crosslinking thiol molecules. Subsequent reaction with sulfhydryl-containing molecules yields thioether linkages.

The extreme strength of the covalent bond derives from the way electrons accumulate between the two atoms. The space occupied by the electrons as they accumulate is not random rather, the two electrons occupy a molecular orbital that is orientated spatially in such a way that the highest probability of finding the electronic charges is directly between the two atomic nuclei. 

---