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Trimethylsilyl)ethoxyacetylene, a stable and easy-handling reagent, serves as an excellent dehydrating agent for the synthesis of carboxylic anhydrides and amides from the corresponding carboxylic acids. By means of this reagent, various types of acid-sensitive carboxylic anhydrides and amides were obtained almost in quantitative yields. Twenty-two examples of carboxylic anhydrides and 12 examples of amides were presented.

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A novel and efficient synthesis of 1 -ethoxyvinyl esters 3a-i from carboxylic acids 4a-i and ethoxyacetylene 5 by using a catalytic amount of ruthenium complex [{RuCI,( p-cymene)},] 6f has been developed. These reagents reacted smoothly with amines and alcohols to give the corresponding N -and 0-acylated compounds in excellent yields. This acylation method has been applied to the synthesis of hydrophilic 3'-N-acylated oxaunomycin derivatives 13a, b.