915764-72-6Relevant academic research and scientific papers
Mild and high-yielding molybdenum(VI) dichloride dioxide-catalyzed formation of Mono-, Di-, Tri-, and tetracarbamates from alcohols and aromatic or aliphatic isocyanates
Stock, Christian,Brueckner, Reinhard
, p. 2309 - 2330 (2012)
Both molybdenum(VI) dichloride dioxide (MoO2Cl2) and its dimethylformamide (DMF) complex catalyze the addition of alcohols to isocyanates giving carbamates. Most additions proceeded to completion at room temperature within 20 min using as little as 0.1 mol% of the catalyst when working on a 1-mmol scale or just 100 ppm working on a 20-mmol scale. Sterically encumbered substrates reacted to completion when 1 mol% of the catalyst was employed. Diols, triols, and tetraols reacted with monoisocyanates likewise, as did monofunctional alcohols and diisocyanates. These pairings furnished di-, tri-, tetra-, and dicarbamates, respectively. Reactants, which were poorly soluble in CH2Cl2 at room temperature required elevating the temperature and possibly choosing a higher-boiling solvent (ClCH 2CH2Cl, DMF) as well. Additions of diols to diisocyanates were feasible, too, giving polycarbamates as we presume. Copyright
Exceptionally active catalysts for the formation of carbamates from alcohols and isocyanates: Molybdenum(VI) dichloride dioxide and its DMF complex
Stock, Christian,Brückner, Reinhard
experimental part, p. 2429 - 2434 (2010/12/18)
Small amounts of MoO2Cl2 or MoO2Cl 2(DMF)2 catalyze carbamate formation from an alcohol and isocyanates: 0.1 mol% of the respective additive allow primary, secondary or tertiary alcohols to add to aliphatic or aromatic isocyanates of varied steric hindrance within 20 minutes at room temperature. Typically the corresponding carbamate resulted in 100% yield. Only particularly hindered substrates required 1.0 mol% of the catalyst while as little as 0.01% sufficed for the phenylcarbamoylation of menthol. Catalytic amounts of DMAP accelerate carbamate formation from certain alcohols and isocyanates, too. Georg Thieme Verlag Stuttgart · New York.
