Trimethylsilyl Isothiocyanate Research Articles

5,6,7,8-Tetrahydroquinolines. Part III. Synthesis of 5,6,7,8-tetrahydroquinoline-8-thiocarboxamides

Reactions of the 8-lithio-derivative of 5,6,7,8-tetrahydroquinolines with trimethylsilyl isocyanate and isothiocyanate, followed by mild hydrolysis, provide a convenient one-step synthesis of 5,6,7,8-tetrahydroquinoline-8-carboxamides and thio-carboxamides respectively. The corresponding secondary thioamides were prepared by a similar reaction with appropriately substituted isothiocyanates.

Reactions of group IV organometallic compounds: XVII. Addition reactions of heptamethyldisilazane with benzoyl iso(thio)cyanate and subsequent eliminations

Benzoyl isocyanate and isothiocyanate react with heptamethyldisilazane to give 1 1 adducts, which exist as mixtures of the isomers involving 1,3-transfer of trimethylsilyl groups. The adducts from benzoyl isothiocyanate decompose thermally by two βB-elimination processes; one, at temperatures below 100°, givesmethyl isothiocyanate, and the other, at 150°, gives trimethylsilyl isothiocyanate. Migration of trimethylsilyl groups was confirmed by means of NMR measurements at various temperatures. This migration is important in determining the course of subsequent βB-elimination reactions.

Reactions of group IV organometallic compounds. Part XII. Benzoyl isocyanate and isothiocyanate as acceptors for N-trimethylsilyldialkylamines

Benzoyl isocyanate reacted readily with equimolar amounts of N-trimethylsilyldialkylamines to give the corresponding NN-dialkyl-N′-trimethylsilyl ureas. Unexpectedly, a further 1 mol. of benzoyl isocyanate reacted with the above 1 : 1 adduct to give 2-dimethylamino-6-phenyl-1,3,5-oxadiazin-4-one and trimethylsilyl benzoate in the case of N-trimethylsilyldimethylamine. On the other hand, benzoyl isothiocyanate did not give the expected 1 : 1 adducts with the same silylamines, but the decomposition products, trimethylsilyl isothiocyanate and NN-dialkylbenzamide, were isolated.