Yapay Zeka Hızlı Bakış & Çıkarımlar
AI InsightThis method is highly selective for conversion of 1° alcohols to alkyl isocyanates in the presence of 2° and 3° alcohols, thiols, and trimethylsilyl ethers.
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Özet
Alkyl isocyanates are prepared in good to excellent yields by treatment of alcohols, thiols, and trimethylsilyl ethers with 2,4,6-trichloro[1,3,5] triazine/n-Bu4NOCN in acetonitrile. This method is highly selective for conversion of 1° alcohols to alkyl isocyanates in the presence of 2° and 3° alcohols, thiols, and trimethylsilyl ethers.
Abstract
Alkyl isocyanates are prepared in good to excellent yields by treatment of alcohols, thiols, and trimethylsilyl ethers with 2,4,6-trichloro[1,3,5] triazine/n-Bu4NOCN in acetonitrile. This method is highly selective for conversion of 1° alcohols to alkyl isocyanates in the presence of 2° and 3° alcohols, thiols, and trimethylsilyl ethers.Isocyanates are useful compounds capable of participating in a variety of reactions, including nucleophilic addition reactions with alcohols and amines, to produce carbamates and ureas, cycloaddition reactions to generate heterocycles, and polymerization reactions to produce commodities, such as polyurethanes.1−3 The high yields and lackof by-products associated with isocyanate chemistry have led to its widespread application in the pharmaceutical, agrochemical, and polymer industries. Typically, aliphatic and aromatic isocyanates are generated from amines reacting with phosgene4−6 or phosgene equivalents, such as diphosgene (trichloromethyl chloroformate)7,8 or triphosgene [bis(trichloromethyl) carbonate],9−10 or via thermal dissociation of carbamic acid derivatives using chloroformates,11−13 diphenylcarbonate,14 or N,N’- carbonyldiimidazole.15 Aryl isocyanates can also be generated from non-amine precursors via the rearrangement of acyl azides (Curtius rearrangement)16−18 and hydroxamic acids (Lossen rearrangement).19−20