Behavior of morpholine and its trimethylsilyl derivative in reactions with trimethylsilyl isocyanate

Objectives . To study the patterns of behavior of morpholine and its trimethylsilyl derivative in reactions with trimethylsilyl isocyanate. Methods . The study employed infrared and nuclear magnetic resonance spectroscopy, as well as elemental analysis. Results . The formation of mixtures of tautomeric forms of silicon-containing urea—N-(trimethylsilyl) morpholine-4-carboxamide and trimethylsilylmorpholine-4-carboximidoate—was established. Conclusions . It is shown that the composition and structure of the resulting products are determined both by the presence of a morpholine substituent at the nitrogen atom and by the type of isocyanate used. Unlike the trimethylsilyl derivative of morpholine, morpholine itself reacts with trimethylsilyl isocyanate to form a mixture of tautomeric forms.