Urea: A Useful and Inexpensive Chemical for Organic Synthesis

Introduction

Urea was the first organic compound to be synthesized from inorganic reagents. This easily accessible chemical has been used as building block in the synthesis of N-carbamoyl-l-amino acids, [¹] cyclic carbonates, [²] and many ­nitrogen-containing heterocycles such as pyridines, [³] pyrimidines, [4] 3,4-dihydropyrimidinones, [5] oxazines, [6] 1,3-oxazin-3-ones, [7] and iminosugars. [8] Another application of urea in carbohydrate chemistry was described earlier. [9] Urea is also employed as source of ammonia in the syntheses of triarylamines, [¹0] imides, [¹¹] and amides. [¹²] Urea is an inexpensive, commercially available colorless crystalline compound, and is soluble in a large range of polar solvents including water. Its recent applications are given below.

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