Process for preparing a synthetic intermediate for preparation of branched nucleosides
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Abstract
A process is provided for the preparation of a key intermediate in the preparation of 2′-branched nucleoside compounds. The process includes contacting a protected precursor 3,4-O-isopropylidene-2-C-substituted-
230 Citations
38 Claims
- 1. A process of preparing a compound of Formula II
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29. A process for preparing a 2-deoxy-2-alkyl-2-halo-lactone compound comprising:
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a) reacting the 2-position of an isopropylidene, 2-alkyl-substituted arabinono-1,5-lactone compound with a leaving group reagent, to provide a 2-deoxy-2-alkyl-substituted-3,4-isopropylidene arabinono-1,5-lactone substituted with a leaving group at the 2-position selected from the group consisting of p-toluene sulfonate, methanesulfonate, trifluoromethanesulfonate, allylsulfonate, 4-nitrobenzenesulfonate, 4-bromobenzenesulfonate, acetate, trifluoroacetate, arylsulfate and alkylsulfonate; b) reacting the product from step a) with a fluorinating agent, a chlorinating agent, a brominating agent or an iodinating reagent to provide a 2-deoxy-2-halo-2-alkyl-substituted-3,4-isopropylidene ribono-1,5-lactone; c) deprotecting the product from step b) with an acid to provide a 2-deoxy-2-halo-2-alkyl-substituted ribono-1,4-lactone as a major product and a 2-deoxy-2-halo-2-alkyl-substituted ribono-1,5-lactone as a minor product; and d) optionally protecting one or more hydroxy groups on either one of the products from step c. - View Dependent Claims (30, 31, 32, 33, 35, 36, 37, 38)
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Specification