Drug synthesis complex mixtures

Laboratory analysis in this type of crime normally focuses on the identification of drugs and precursors to determine the synthesis route(s) and to estimate the production capability. GC is a highly effective tool in these analyses. Since many samples may contain complex mixtures of precursors, impurities, and byproducts, high resolution is essential and the use of capillary columns are recommended. 

The high cost of the HPLC-NMR system is of course a factor which must be taken into consideration. Since most laboratories have seen the value of NMR in its traditional form, it is only necessary to add an HPLC system, an appropriate flow probe and a flow-control unit to an existing spectrometer to enable HPLC-NMR experiments to be performed. The cost of these accessories, or even the cost of a complete system dedicated to HPLC-NMR, is offset by the efficiency of the method. The laborious extraction of minor components from complex mixtures followed by off-line analysis or in the case of synthetic drugs the synthesis of radiochemically... 

Fluorous chemistry integrates the characteristics of solution-phase reactions and the phase tag strategy developed for solid-phase chemistry [7-15], Perfluoroalkyl chains instead of polymer beads are used as the phase tags to facilitate the separation process. In 2001 the Curran group first reported the concept of fluorous mixture synthesis (FMS) for solution-phase library synthesis [16], FMS is able to produce individual pure compounds without the effort of deconvolution. It adapts literature procedures to synthesize complex natural products, their enantiomers and diastereomers. FMS can also be used for the development of new synthetic protocols and to make novel drug-like molecules [17, 18],... 

The cyclization of ethylenediamine (EDA) and propylene glycol (PG) over a mixture of zinc and chromium oxides to 2-methylpyrazine (MP) is a basic step in the synthesis of 2-amidopyrazine, a well-known antitubercular drug. This is a highly complex reaction in which EDA and PG each react independently to give a variety of products, as shown in Table 5.1. (Forni and Miglio, 1993). We desire to find the number of independent reactions from this set. 

There are few examples where the absolute stereochemistry is determined in the PKR. Verdaguer has demonstrated the use of a bidentate phosphorous-sulphur ligand to provide an enantiopure cyclopentenone in for the synthesis of the HIV drug (-)-abacavir. The achiral alkyne cobalt complex is generated first in 1 h at room temperature. Heating with enantiopure R,S-ligand 102 provides a separable mixture of diastereomeric... 

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