Trichloroacetyl isocyanate

UsesTrichloroacetyl isocyanate was used in catalytic one-pot dehydrative glycosylation of 1-hydroxy carbohydrate. It was also used as a reagent for the conversion of alcohols to carbamates.

General DescriptionConformational stability and vibrational IR and Raman spectra of trichloroacetyl isocyanate has been investigated. Trichloroacetyl isocyanate is commonly employed as in situ derivatizing reagent for the 13C NMR studies of alcohols, phenols and amines. It undergoes 1,5-cycloaddition reaction with anhydro-2-deoxy-D-erythro- and -L-threo-pent-1-enitols and 1,5-anhydro-2-deoxy-D- and -L-arabino-hex-1-enitols to yield [2+2] and [4+2] cycloadducts.

PreparationTrichloroacetyl isocyanate can be obtained by reacting 2,2,2-trichloroacetamide with oxalyl chloride. Procedure: A reaction mixture of 2,2,2-trichloroacetamide (100 g, 616 mmol, 1.0 eq) in (COCl)2 (725 g, 5.71 mol, 500 mL, 9.28 eq) was heated to 70°C for 24 hours. The reaction mixture was concentrated under vacuum. To the mixture was added 1,2,4-trichlorobenzene (500 mL) and (COCl)2 (116 g, 914 mmol, 80 mL, 1.48 eq). The reaction mixture was stirred at 100°C for 5 hours. Heat to 125°C for 15 hours. The mixture was then heated to 140°C for 5 hours. The reaction mixture was distilled under water pump (72°C-76°C fractions) to give trichloroacetyl isocyanate (60 g, 319 mmol, 52% yield) as a colorless oil.