Some chemical transformations of 6-alkynylated purines

6-Alkynylated purines were conveniently transformed to the corresponding 6-alkyl- and 6-alkenylpurines by three methods: (i) hydrogenation with 10% palladium-carbon or palladium acetate-sodium borohydride, (ii) addition of hydrogen halides or water and (iii) formal addition of diethylamine to the triple bond. Some of the products exhibited strong cytokinin activity.