ring main
4.:In this paper, we proved the following result: If R is a regular local ring or principal ideal do-main with char R≠0,G is a finitely generated abelian group,then K0RG is torsion-free.
7.It was rearranged under the action of protonic acid to open the four-ring,and then hydrated to form the main product: 4-(1-methyl-1-hydroxyethyl)-1-cyclohexene-1-ethanol acetic ester, and its corresponding alcohol by further hydrolysis.

