Glove boxes synthesis

The UV-Vis spectral detection of an intermediate in the catalytic reductive alkylation reaction provides only circumstantial evidence of the quinone methide species. If the bioreductive alkylating agent has a 13C label at the methide center, then a 13C-NMR could provide chemical shift evidence of the methide intermediate. Although this concept is simple, the synthesis of such 13C-labeled materials may not be trivial. We carried out the synthesis of the 13C-labeled prekinamycin shown in Scheme 7.5 and prepared its quinone methide by catalytic reduction in an N2 glove box. An enriched 13C-NMR spectrum of this reaction mixture was obtained within 100 min of the catalytic reduction (the time of the peak intermediate concentration in Fig. 7.2). This spectrum clearly shows the chemical shift associated with the quinone methide along with those of decomposition products (Fig. 7.3). 

Chloromethyl methyl ether is an alkylating agent and very poisonous.Therefore this synthesis must be carried out with rubber gloves under a hood, preferentially in a glove box. 

However, if a glove box is not available for the synthesis, the reaction can also be performed in a dry, inert solvent which covers the reaction mixture and protects it from hydrolysis. An advantage of this procedure is that the solvent, which is typically an alkane, can also react as a heat carrier in the exothermic reaction. After completion of the reaction the ionic liquid forms a second layer below the solvent. The solvent can be removed by simple distillation before use of the ionic liquid. However, the ionic liquid will be contaminated with the organic solvent, which has to be removed under vacuum. 

The solution of aluminum trihydride used in this synthesis is prepared by the reaction of 100% sulfuric acid with lithium tetrahydridoaluminate(l —) in dry tetrahydrofuran.3 Under nitrogen flow, a stoichiometric amount of the sulfuric acid is added dropwise by syringe at 0° to a solution of lithium tetrahydridoaluminate(l —) in dry tetrahydrofuran. The apparatus used is just like that shown in Fig. 2, except that an ice bath is used to cool the reaction flask and thus prevent ether cleavage. As the sulfuric acid is added to the lithium tetrahydridoaluminate(l —), a precipitate of lithium sulfate forms and hydrogen is evolved. For this reason, the reaction must be carried out in a hood. After all the sulfuric acid has been added, the resulting slurry is stirred for 2 hr, then filtered in a glove box.4,5 The filtrate, a clear solution of aluminum trihydride in tetrahydrofuran, is stored in the refrigerator at -20° until it is needed. 

Electrochemical synthesis of electroconducting polymers such as polyarene [28— 31], polypyrrole [32-34], polythiophene [35], and polyaniline [36, 37] has been carried out in moisture sensitive chloroaluminate ionic liquids. However, the polymer hlms are decomposed rapidly by the corrosive products like HCl generated by hydrolysis of the ionic liquids. In addition the treatment of the chloroalminate ionic liquids requires a special equipment such as glove box. 

The most general method for the preparation of solid phosphides is from the elements however, there are several problems to overcome in that highly electropositive metals are often air- and moisture-sensitive, so that the educts and often the products must be handled under inert conditions (glove box or Schlenk technique). A well described example for the synthesis of the air- and moisture-sensitive phosphides Na3 7 and Na3Pii has been described. ... 

To make the reactive fulleride compound KeCeo in the Fe-Ceo synthesis, fullerenes and a slight excess of potassium were sealed in a glass tube under vacuum and heated for approximately four days at 250 °C. Both solid-state NMR and Raman spectroscopy were employed to determine that the KeCeo compound was in fact synthesized. The KeCeo product was then reacted in an inert atmosphere with cyclopentadienyl-iron-dicarbonyl-iodide (CpFe(CO)2l) in tetrahydrofuran (THF) to form the complex. The recovered product was dried in an inert atmosphere. Manipulations of air-sensitive materials were carried out in a glove box or using standard Schlenk techniques. THF was distilled just prior to use from sodium benzophenone ketyl. Ceo was obtained from Aldrich, and CpFeCCOjol was obtained from Strew. 

All reagents, solvents and apparatus must be dry, and moisture and oxygen should be excluded. All operations should be carried out in a glove-box or by standard Schlenk techniques. Chemicals used in the following synthesis are mostly commercially available. Abbreviations dmpe = l,2-Bis(dimethylphosphino)ethane Cp = cyclopentadi-enyl Cp = pentamethylcyclopentadienyl. 

Many organometallics are air sensitive, so the development of techniques which permit synthesis and characterization in a vacuum or inert atmosphere are central to the field. Even though the manipulation of air-sensitive compounds has been successfully practiced for a long time, the techniques have undergone constant improvement. For convenience these may be classified as vacuum line, bench-top inert atmosphere, and glove box techniques but as shown in this book combinations of them are common. 

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