[reaction: see text] A polymer-supported catalyst for Huisgen's [3+2] cycloaddition reaction between azides and alkynes was prepared from copper(I) iodide and Amberlyst A-21. This catalyst was then used in an automated synthesis of 1,4-disubstituted 1,2,3-triazoles giving access to these products in good yields. The catalyst has shown good activity, stability, and recycling capabilities.

Molecular sieves catalyse pyridinium chlorochromate and pyridinium dichromate oxidation and so give rise to an efficient synthesis of ketonucleosides and ketosugars a t room temperature.PYRIDINIUM CHLOROCHROMATE (PCC) and pyridinium dichromate (PDC)2 allow mild and large scale oxidation of a wide range of alcohols to carbonyl compounds in methylene chloride at room temperature. Unfortunately, in the case of nucleosides these conditions lead to a very long and incomplete reaction.In order to enhance the reactivity of PCC and P P C towards nucleosides at room temperature we have tried to promote the reactions by using insoluble inorganic compounds which are active in the case of chromic3t4 or permanganate oxidations.6 Since attempts to catalyse the reaction by celite, alumina, and silica gel were unsuccessful we performed the oxidation using molecular sieves and found that the reaction rate was considerably accelerated (Table 1).