Hydrophilic building blocks

Uses Humectant, emollient in cosmetics sweetener for beverages, chewing gum, candy, chocolate, pharmaceutical tablets and coatings excipient for pharmaceutical syrups and medicated candies taste masking agent to mask unpleasant bitter taste of actives in pharmaceutical syrups and oral care prods. coolant for oral care prods. hydrophilic building block in fine chems. 

As with lipids, amphiphihc block copolymers can be divided into a polar moiety (the head ) and an unpolar moiety, referred to as tail consequently, they are also able to form supramolecular associates in aqueous systems. Depending on the exact structure of the block copolymer, the resultant supramolecular stmcture can vary, and is controlled by the polymer architecture examples include the lengths of the individual hydrophilic building blocks and the overall hydrophihc/hydrophobic balance. Just like phospholipids, block copolymers (notably triblock copolymers) can form supramolecular hollow spheres with both hydrophihc and hydrophobic compartments, that allow for the encapsulation of hydrophihc and hydrophobic substances. In analogy to liposomes, these associated structures are referred to as polymersomes. 

The functionalization via 1,3-dipolar cycloaddition has been used to drastically increase the solubility of Cgo in the common organic solvents. The addition of hydrophilic building blocks, such as oligoethylene glycol chains bearing ammonium salts to the extremely hydrophobic spheroid of C o, led to the formation of amphiphilic derivatives soluble in polar media (Figure 2.5). ... 

Amino acids, the building blocks of giant protein molecules have a carboxyl group and an amino group attached to the same carbon atom. A protein is a linear polymer of amino acids combined by pepfide linkages. Twenfy different amino acids are common in proteins. Their side chains, which have a variety of chemical properties, control the shapes and functions of proteins. Some of these side chains are hydrophobic, others are hydrophilic, and still others occur either on the surface or the interiors of proteins. 

Equally simple entries—in fact, one-pot reactions each— lead from D-ftuctose to A -heterocycles of the imidazol, pyrrole, and pyridine type (Scheme 2.11), all of which, due to their hydrophilic substitution patterns, are considered useful building blocks to pharmaceuticals. 

The main feature of (meth)acrylate-based support materials is the broad diversity of monomers that is commercially available and that can thus can be used for the fabrication of monoliths. The resulting (meth)acrylate monoliths consequently cover a wide spectrum of surface chemistries and properties. The scope of monomers includes hydrophobic, hydrophilic, ionizable, chiral, as well as reactive (meth)acrylate building blocks [53]—the most popular being mixtures of butyl methacrylate and ethylene dimethacrylate (BMA/EDMA) or glycidyl methacrylate and ethylene dimethacrylate (GMA/EDMA) as cross-linker. 

Building blocks are amphiphiles, which have a delicate balance between the hydrophilic and hydrophobic group crucial to facilitate self-assembly. The peptide component serves to precisely control this balance, and the enzymatic reaction serves to alter it in favour of self-assembly. As illustrated in Fig. 3, the molecular switch may involve (1) phosphatase-catalysed removal of a (phosphate) group from the precursor to control the electrostatic balance (reaction (i) in Fig. 3) (2) hydrolysis of alkyl esters by hydrolases to change the amphiphilic balance (reaction (ii) in Fig. 3) or (3) condensation between two non-self-assembling precursors via a condensation reaction, e.g. involving protease-catalysed amide synthesis to alter the hydrophilic/hydrophobic balance (reaction (iii) in Fig. 3). A number of examples of each type are summarised in Table 1. 

Carbohydrates are characterized by the presence of polyhydroxylic aldehyde or poly-hydroxylic ketone structures or polymers of such units. Sugars and polysaccharides have definite three-dimensional structures that are important for many biological functions. They are hydrophilic and thus easily accessible to aqueous reaction mediums. The chemistry of bioconjugation using carbohydrate molecules begins with an understanding of the building blocks of polysaccharide molecules. 

---