52050-59-6Relevant academic research and scientific papers
Benzolactams. 4. Reaction of 3′,4′- or 4′,5′-Dialkoxy-Substituted 1-(2′-Bromobenzyl)-2-ethoxycarbonyl-1,2,3,4-tetrahydroisoquinolines with Alkyllithium. 1,2 and 1,4 Additions of Alkyllithium to Benzolactams
Orito, Kazuhiko,Miyazawa, Mamoru,Kanbayashi, Ryo,Tatsuzawa, Takashi,Tokuda, Masao,Suginome, Hiroshi
, p. 7495 - 7500 (2007/10/03)
Treatment of 1-(2′-bromo-3′,4′-dialkoxybenzyl)-1,2,3,4- tetrahydroisoquinoline carbamates, 1a,c, with excess alkyllithium gave 8-oxoberbines, 2a,c, which were successively attacked in situ with another molecule of alkyllithium to give 1,2 and/or 1,4 addition products. A primary alkyllithium, such as MeLi or BuLi, gave a 1,2 addition product, 8-methyleneberbine 9a or 8-butylideneberbine 3a. t-BuLi preferred 1,4 addition, followed by elimination of the alkoxy group, to give 9-tert-butyl-8-oxoberbine 6a or 7c. s-BuLi gave a mixture of 1,2 and 1,4 addition products, 1-[2′-(2″-methylbutyryl)benzyl]-1,2,3,4-tetrahydroisoquinoline 4a and 9-s-butyl-8-oxoberbine 5a. Similar treatments of carbamate 1b having no alkoxy group at its 3′ position gave 1,2 addition products, 8-butylideneberbine 3b, 1-[2′-(2″-methylbutyryl)benzyl]-1,2,3,4-tetrahydroisoquinoline 4b, and 1-(2′-pivaloylbenzyl)-1,2,3,4-tetrahydroisoquinoline 6b, in all cases. Reactions of 1a with s-BuMgCl and isoPrMgCl also gave the 1,4 adduct, 5a, and its 9-isoPr analogue, 12a. Treatment of 9a with excess NaBH4 in AcOH gave (±)-coralydine (10b).
