1. Bachhawat JN, Mathur NK (1971) Indian J Chem 9:1335
2. Thiagarajan V, Venkatasubramanian N (1970) Indian J Chem 8:809
3. Mukherjee N, Banerjee KK (1981) J Org Chem 46:2323
4. Das CM, Indrasenan P (1986) Indian J Chem 25A:605
5. Saroja P, Kandlhkar S (1990) J Indian Chem Soc 67:878