(Z)-6-(4-Hydroxy-3-methylbut-2-en-1-ylamino)purine, (Z)-zeatin, and the isomeric (Z)-isozeatin, both free from the E isomers, were prepared using the cycloaddition of the in situ generated tert-butyl nitrosoformate on isoprene. A mixture of tert-butyl 5(and 4)-methyl-3,6-dihydro-2H-1,2-oxazine-2-carboxylates thus formed was deprotected and reductively cleaved to (Z)-4-amino-2(and 3)-methylbut-2-en-1-ols, which were chromatographically separated and finally alkylated with 6-chloropurine to give the title compounds.
使用现场生成的叔丁基
亚硝酸酯在
异戊二烯上进行环加成反应,制备了(
Z)-6-(
4-羟基-3-甲基丁-2-烯-1-基)
嘌呤、(
Z)-
玉米素和同分异构体(
Z)-
异玉米素,均不含
E异构体。由此形成的叔丁基5(和4)-甲基-3,6-二氢-2
H-1,2-噁啉-2-
羧酸酯混合物被去保护并还原裂解为(
Z)-4-
氨基-2(和3)-甲基丁-2-烯-1-醇,经过色谱分离后最终与
6-氯嘌呤烷基化,得到了所述化合物。