Treatment of a wide variety of 2-(2-arylhydrazino)tropones with ethanolic acid at 50–80 °C readily gave the benzidine type rearrangement products, i.e. 2-amino-5-(4-aminoaryl)tropones, which in turn were conveniently led to the corresponding 5-aryltropolones that can be utilized for synthesizing B-ring-open analogues of colchicine.
在 50–80 °C 下用乙醇酸处理各种 2-(2-芳基肼基) 托酮很容易得到联苯胺型重排产物,即 2-氨基-5-(4-氨基芳基)托酮,这反过来又很方便导致相应的 5-芳基托酚酮可用于合成秋水仙碱的 B 环开环类似物。
NOZOE, TETSUO;TAKASE, KAHEI;YASUNAMI, MASAFUMI;ANDO, MASAYOSHI;SAITO, HIR+, BULL. CHEM. SOC. JAP., 62,(1989) N, C. 128-142
Synthesis and Reactions of 2-Arylhydrazinotropones. II. Synthesis of 5-Aryltropolones and B-Ring-Open Colchicine Analogues via Benzidine Type Rearrangement of 2-(2-Arylhydrazino)troponesa
Treatment of a wide variety of 2-(2-arylhydrazino)tropones with ethanolic acid at 50–80°C readily gave the benzidine type rearrangement products, 2-amino-5-(4-aminoaryl)tropones, besides minor amounts of byproducts of various type. The main products were conveniently led to the corresponding 5-aryltropolones. Similarly, 2-(2-arylhydrazino)tropones bearing an isopropyl and isopropenyl group at the 4-position