Collect. Czech. Chem. Commun.
1999, 64, 696-702
https://doi.org/10.1135/cccc19990696
A Hetero Diels-Alder Access to (Z)-Zeatin and (Z)-Isozeatin
Vladimír Tolmana,*, Jan Hanuša and Petr Sedmerab
a Isotope Laboratory, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic
b Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic
Abstract
(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.
Keywords: Cytokinins; Zeatin; Nitrosoformates; Diene synthesis; 3,4-Dihydrooxazines; Cycloadditions; Diels–Alder reaction; Purines.
