Number | Date | Country | Kind |
---|---|---|---|
3938054 | Nov 1989 | DEX | |
4029092 | Sep 1990 | DEX |
Number | Date | Country |
---|---|---|
0254426 | Jun 1987 | EPX |
0253213 | Jan 1988 | EPX |
0299694 | Jan 1989 | EPX |
51-43714 | Apr 1976 | JPX |
Entry |
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Ogura et al, Tetrahedron Letters, No. 4, 375-378, 1978. |