Blocking functional groups using

Thus, anhydride reagents may be used both to block functional groups and to convert an existing functional group into a carboxylic acid. 

The molecular stmcture of the copolymers is also important. Molecular-weight measurements (osmometry, gpc) and functional group analysis are useful. Block copolymers require supermolecular (morphological) stmctural information as well. A listing of typical copolymer characterization tools and methods is shown in Table 6. 

The preferred substrates of acetyltransferases are amino-groups of antibiotics, like chloramphenicol, strepto-gramin derivatives, and the various aminoglycosides. The modification is believed to block a functional group involved in the drug-target-interaction. All acetyltransferases use acetyl-coenzyme A as cofactor. 

When the same monomer is used to build up a polymer, it is termed a homopolymer. Copolymers have two different monomers or functional groups, and terpolymers have three groups. There are even tetrapolymers available. These polymers may be further classified, for example, as random, graft, or block copolymers. Block copolymers, which have alternating sections of specific molecular chains, are used in BW formulations (but are more commonly found in CW programs). 

Many pharmacologically active compounds have been synthesized using 5-bromoisoquinoline or 5-bromo-8-nitroisoquinoline as building blocks.6 7 8 9 10 11 The haloaromatics participate in transition-metal couplings 81012 and Grignard reactions. The readily reduced nitro group of 5-bromo-8-nitroisoquinoline provides access to an aromatic amine, one of the most versatile functional groups. In addition to N-alkylation, TV-acylation and diazotiation, the amine may be utilized to direct electrophiles into the orthoposition. 

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