Generic structures, characterising

In contrast to canonical linear notations and connection tables (see Sections 2.3 and 2.4), fragment codes arc ambiguous. Several different structures could all possess an identical fragment code, because the code docs not describe how the fragments arc interconnected. Moreover, it is not always evident to the user whether all possible fi aginents of the stmetures ai e at all accessible. Thus, the fragments more or less characterise a class of molecules this is also important in generic structures that arise in chemical patents (sec Section 2.7.1)... 

The human oxytocin receptor gene was isolated and characterised in 1994 [122], heralding the development of modern cloned receptor screening. The oxytocin receptor belongs to the Family A series of G-protein coupled 7-transmembrane receptors (GPCRs). A schematic representation of the generic structure of 7TM receptors is shown in Figure 7.3. 

The different t es of variation which characterise generic structures can be summarised as ... 

Flash photolysis and laser flash photolysis are probably the most versatile of the methods in the above list they have been particularly useful in identifying very short-lived intermediates such as radicals, radical cations and anions, triplet states, carbenium ions and carbanions. They provide a wealth of structural, kinetic and thermodynamic information, and a simplified generic experimental arrangement of a system suitable for studying very fast and ultrafast processes is shown in Fig. 3.8. Examples of applications include the keton-isation of acetophenone enol in aqueous buffer solutions [35], kinetic and thermodynamic characterisation of the aminium radical cation and aminyl radical derived from N-phenyl-glycine [36] and phenylureas [37], and the first direct observation of a radical cation derived from an enol ether [38],... 

In 1981 workers of the Takeda Company described (23) the isolation of the monocyclic P-lactams sulfazecin (24) and isosulfazecin (25) from various species of Pseudomonas. This was the first reported case of P-lactam antibiotics being produced by bacteria. Shortly afterwards chemists at the Squibb Research Institute also reported a number of similar monocyclic structures of bacterial origin (26). All these compounds were characterised by the presence of a sulphonic acid grouping in the A(l)-position of the P-lactam ring as in (30). Generically called the monobactams, the known structural types are shown in Table 2. 

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