Strategies, vii

In recent years, a variety of aryl boronic acids are commercially available, albeit in some cases they may be expensive for large scale purposes. During our work in the mid-1990 s boronic acid (II) was not commercially available and so two different protocols were used to prepare this acid. The first approach involved the transmetallation with n-butyl lithium of aryl bromide (I) and trapping the lithio species generated with trialkyl borate followed by an acid quench. Aryl bromide (I) is easily prepared by reaction of o-bromobenzenesulfonyl chloride with 2-propanol in the presence of pyridine as a base. The second approach was a directed metallation of isopropyl ester of benzene sulfonic acid (VII), to generate the same lithio species and reaction with trialkyl borate. The sulfonyl ester is prepared by reaction of 2-propanol with benzenesulfonyl chloride. From a long-term strategy the latter approach is... 

Three ligand-stabilized dioxorhenium(VII) compounds were synthesized to allow direct evaluations of their reactivities (32). The strategy was to use an alkoxide-thiolate chelate rather than a dithiolate. Compounds 13-15 were obtained. 

The approaches and strategies presented in this chapter are intended to overcome these issues for CE methods. Recendy a more advanced approach toward chromatographic method development was introduced in pharmaceutical product development that also is beneficial for CE methods. In the advanced approach (i) the voice of the customer is captured, (ii) key process input variables are identified, (iii) critical to quality (CTQ) factors are determined, (iv) several method verification tests are installed, (v) proactive evaluation of method performance during development is performed, (vi) continuous customer involvement and focus is institutionalized, and (vii) method capability assessment (suitability to be applied for release testing against specification limits) is established. 

Diem, M., Chiriboga, L. and Yee, H. (2000) Infrared spectroscopy of human cells and tissue. VII. Strategies for analysis of infrared tissue mapping data and applications to liver tissue. Biopolymers (Biospectroscopy) 57, 282-90. 

Archbold, E., Mitchel, S., Hanson, D., Hull, B., Galo, L. M., and Monzon, O. (1991). Serum-pooling strategies for HIV screening Experiences in Trinidad, Ecuador, and the Phillippines. VII International Conference on AIDS Abstract Book, 2, 331. 

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