A novel and practical asymmetric synthesis of eptazocine hydrobromide

• Ruipeng Li,
• Zhenren Liu,
• Liang Chen,
• Jing Pan,
• Kuaile Lin and
• Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 2340–2347, doi:10.3762/bjoc.14.209

• . of China 10.3762/bjoc.14.209 Abstract In order to prepare eptazocine hydrobromide effectively, a novel, mild and practical asymmetric process was developed starting from 1-methyl-7-methoxy-2-tetralone under the catalysis of N-(p-trifluoromethylbenzyl)cinchonidinium bromide. The reaction conditions

• were optimized to obtain the product in excellent overall yield and purity. Keywords: alkylation; asymmetric catalysis; eptazocine; Mannich cyclization; Introduction Eptazocine hydrobromide (1, Scheme 1), (1S,6S)-1,4-dimethyl-2,3,4,5,6,7-hexahydro-1H-1,6-methanobenzo[e]azonine-10-ol hydrobromide

• are engaged in the development of a concise and efficient asymmetric synthetic route for eptazocine hydrobromide (1), with the same material and catalyst. Results and Discussion Herein, we developed a new, practical and resolution-free preparation of 1 (Scheme 3) using the asymmetric alkylation of 2

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• afford a benzothiepinone (Scheme 13) [32]. In the particular case of 65a, oxidation to the corresponding sulfone 66 followed by a Mannich reaction with various aldehydes leads to a plethora of complex polycyclic structures 67a–e, which may be viewed as analogues of eptazocine 68 [32]. Oxidation to the