CO 2 gas trapped with a primary or secondary amine as a carbamate salt in the presence of DBU reacts with triphenylphosphine and 1-chlorobenzotriazole (BtCl) to form a carbamoylbenzotriazole urea, which reacts with para-toluenesulfonamide under solvent-free conditions to produce N-sulfonyl ureas such as tolbutamide.
Room temperature E1cB N-N cleavage of oxazolidinone hydrazides via N-alkylation with diethyl bromomalonate and potassium or caesium carbonate as base in acetonitrile is presented. The new method has a much improved chemoselectivity, which is illustrated by a concise total synthesis of the piperidine iminosugar (+)-1,4-dideoxyallonojirimycin.
Acetals: A New Organocatalysis Chemotype for One-Pot Enantioselective -Amination. -Conditions for the enantioselective -amination of acetals with azodicarboxylate (II) are elaborated. Subsequent reduction affords the corresponding amino alcohols with moderate to high levels of enantioselectivity. The -amination of lactol (VIII) is achieved under modified conditions. -(MSUTU, A.; HUNTER*, R.; Tetrahedron Lett. 55 (2014) 14, 2295-2298, http://dx.
Facile One-Pot Synthesis of Carbamoylbenzotriazoles Directly from CO 2 : Synthesis of Tolbutamide. -Various title compounds are prepared following a novel method which uses amines and CO2. The conversion of these products to sulfonylureas including the antidiabetes drug tolbutamide (XIb) is demonstrated. -(HUNTER*, R.; MSUTU, A.; DWYER, C. L.; EMSLIE, N. D.; HUNT, R. C.; BEZUIDENHOUDT, B. C. B.; Synlett 2011, 16, 2335-2338, http://dx.doi.org/10.1055/s-0030-1261222 ; Dep. Chem., Univ. Cape Town, Rondebosch, Cape Town 7701, S. Afr.; Eng.) -Mais 05-087
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