Number | Date | Country | Kind |
---|---|---|---|
2805620 | Feb 1978 | DEX |
Number | Date | Country |
---|---|---|
2514759 | Sep 1975 | DEX |
Entry |
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R. C. Fuson, "Adv. Org. Chem.", pp. 18-21, and 58-61, Wiley, N.Y., (1950). |
Elderfield, "Heterocyclic Compounds", vol. 3, Chapman & Hall, Ltd., New York, N.Y., (1952), pp. 97-98. |