Mammalian Alkaloids:<i>O</i>-Methylation of (±)-Norcoclaurine-1-carboxylic Acid and Related Isoquinolines Including (<i>S</i>)- and (<i>R</i>)-Norcoclaurine with<sup>14</sup>C-Labeled<i>S</i>-Adenosyl-<scp>L</scp>-Methionine in Presence of Mammalian Catechol<i>O</i>-Methyltransferase
作者:Yasuo Sekine、Cyrns Crevelling、Maureen Bell、Arnold Brossi
DOI:10.1002/hlca.19900730222
日期:1990.3.14
observed with (−)-(S)- and (+)-(R)-norcoclaurine (2a and 2b, resp.), affording 80% of 6-O-methylated isoquinoline 12 and 20% of the 7-O-methylated isomer 11 from 2a, and the reversed proportion of 12 and 11 from 2b. Synthesis of the reference amino acid 8 was achieved by Pictet-Spengler condensation of O-benzyl-protected dopamine 17 with benzyl-protected keto acid 20 ( 21) followed by methylation with
(±)-Norcoclaurine -1-羧酸(5)和所述派生dihydroisoquinolinone 6(存在quinonemethide 6在pH 7),得到,甲基化与14 C标记的小号-adenosyl -L-甲硫氨酸在哺乳动物儿茶酚的存在O-甲基转移酶,分别是7- O-甲基化同源物7和9。用(-)-(S)-和(+)-(R)-去甲紫丁香碱(分别为2a和2b)观察到了O-甲基化的高立体选择性(分别为2a和2b),得到80%的6- O-甲基化的异喹啉12和20%的7- O-甲基化的异构体11来自2a,以及12和11的比例与2b相反。参照氨基酸8的合成是通过O-苄基保护的多巴胺17与苄基保护的酮酸20(21)的Pictet-Spengler缩合,然后用重氮甲烷(22 + 23)甲基化并通过酸除去保护基来实现的水解。人们认为,诸如5是构成与网状茶碱相关的异喹啉生物合成中的重要前体。