Tietze reagent

Schreiber and co-workers have detailed the utility of the Tietze reagent, 2-formylmalondialdehyde, in stereoselective [4 + 2] cycloadditions with the Patemo-Buchi photoadducts derived from furan and aldehydes for use in the stereoselective assemblage of highly oxygenated aliphatic substrates [Eq. (13)].98... 

Tietze and coworkers developed two new domino approaches in the field of combinatorial chemistry, which are of interest for the synthesis of bioactive compounds. Combinatorial chemistry can be performed either on solid phase or in solution using parallel synthesis. The former approach has the advantage that purification of the products is simple and an excess of reagents can be used. This is not possible for reactions in solution, but on the other hand all known transformations can be used. The Tietze group has now developed a protocol which combines the... 

Gas Chromatography-Mass Spectrometry. A positive screening result for amphetamine or methamphetamine (or MDA, MDEA, and MDMA) obtained by immunoassay is confirmed by GC-MS analysis of the urine specimen. A GC-MS method for amphetamine and methamphetamine that can be adapted to include MDA, MDMA, and MDEA is included in the Chapter 34 Appendix that is found on this book s accompanying Evolve site (http //evolve.elsevier.com/ Tietz/textbook/). With this method, it should be noted that specimens containing ephedrine or pseudoephedrine occasionally have been reported to test positive for methamphetamine when 4-carbethoxyhexafluorobutyryl chloride (4-CB) is used as a derivatizing reagent. ... 

The domino reaction allows the formation of two or more bonds in one process and meets the requirements of the modem synthesis (Tietze et al., 2006). In contrast with the traditional stepwise synthesis, such a process provides a wide range of possibilities for the efficient assembly of complex molecules from simple starting materials in a single step, and the tedious workup and isolation procedures of intermediates are avoided. Moreover, additional solvents and reagents can be saved by using such a method. Recently, heterogeneous Cu-catalyzed domino reactions have been applied for the efficient and convenient elaboration of heterocyclic molecules. 

Enzyme Preparation. This enzyme from rabbit muscle is available commercially (Boehringer Manheim Corp.) or may be prepared by the method of Tietz and Ochoa. Further purification may be achieved by the technique of Cottam et al.° Pyruvate kinase activity is conveniently assayed by coupling the reduction of pyruvate, produced from phos-phoenolpyruvate, to lactate, catalyzed by lactate dehydrogenase. The NADH consumed in this reaction is assayed spectrophotometrically. Studies of reversible inhibition are carried out directly in the reaction cuvette, with appropriate controls to eliminate the possibility that inhibition is due to inactivation by DMPA of the lactate dehydrogenase or other assay reagents. 

In spite of the explosive growth of enantioselective organocatalysed domino reactions in the last decade,an increasing number of enantioselective metal-catalysed domino processes have been developed in the last few years. A domino reaction has been defined by Tietze as a reaction which involves two or more bond-forming transformations, taking place under the same reaction conditions, without adding additional reagents and catalysts, and in which the subsequent reactions result as a consequence of the functionality... 

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