Reaction of dibutyltin oxide with amides in presence of traces of water: multinuclear NMR study and mechanism

• Published in: Journal of organometallic chemistry Vol. 575; no. 2; pp. 286 - 300
• Main Authors: Gimenez, Jérôme, Michel, Alain, Pétiaud, Roger, Llauro, Marie-France
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1999
• Subjects: Amide and hydrolysis; Distannoxane; Tin; Tin; Distannoxane; Amide and hydrolysis
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(98)01008-0

The product of the reaction of primary and secondary amides with dibutyltin oxide is shown to be a dimeric 1,3-diacyloxytetrabutyldistannoxane. The reaction was studied in bulk with model amides at 180°C, avoiding perfect anhydrous conditions, in view to be transposable to transamidification with reactive extrusion process. The formation of an intermediate compound of the type 1-acyloxy-3-alkylaminotetrabutyldistannoxane is pointed out. With an excess of amide, the presence of water leads to the dimeric 1,3-diacyloxytetrabutyldistannoxane. Without an excess of amide, the hydrolysis of this intermediate leads to a more complex tetrastannoxane structure associated in a more or less perfect ladder-like structure including partially hydrolyzed and condensed forms of the distannoxane. The dimeric 1-acyloxy-3-alkoxytetrabutyldistannoxanes resulting from the reaction of esters with dibutyltin oxide are shown to give a similar stannoxane structure after hydrolysis. All the products were characterized in solution by 1H-, 13C- and 119Sn-NMR spectroscopy. On the basis of the spectroscopic analysis, a mechanism of the reaction is proposed and discussed.