e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Intra-and Intermolecular [3++ 2] Cycloadditions of Aldehyde or Ketohydrazones
…, Y Hayashi, M Nakano, K Teramura
Index: Shimizu, Tomio; Hayashi, Yoshiyuki; Nakano, Mineo; Teramura, Kazuhiro Bulletin of the Chemical Society of Japan, 1984 , vol. 57, # 1 p. 134 - 141
The reaction of several 2-(alkenyloxy) benzaldehydes (or 1-naphthaldehydes)(1) with arylhydrazine hydrochlorides leads to intramolecular [3++ 2] cycloadducts, 3-substituted 2- aryl-1, 2, 3, 3a, 4, 9b (or 1, 2, 3, 3a, 4, 11c) hexahydro [1] benzopyrano (or naphtho [1′, 2′: 5, 6] pyrano)[4, 3-c] pyrazole hydrochlorides (4), in good yields. Free bases (5) were obtained in high yields after the treatment of 4 with triethylamine. The thermal treatment of ...