| 摘要 |
A novel process is disclosed for the preparation of cyclic ureas having the formula <IMAGE> wherein A is a straight chain alkylene radical of 2 to 4 carbon atoms, inclusive, wherein said alkylene radical can be substituted by at least one member selected from the group consisting of halogen, lower alkyl, lower alkoxy, aryl, aryloxy, aralkyl, and cycloaklyl. An alkylene diamine having the formula NH2ANH2, wherein A is defined as above, is reacted in a solvent with carbonyl sulfide to form the corresponding N-( omega -aminoalkyl)thiocarbamic acid (NH2ANHCOSH) or zwitterion thereof. The thiocarbamic acid is then heated to form the cyclic urea.
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