- A facile method for deprotection of trityl ethers using column chromatography
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A mild, efficient and inexpensive detritylation method is reported that uses trifluoroacetic acid on a silica gel column to obtain pure, detritylated compounds in one-step. This method is applicable to acid stable as well as acid sensitive compounds with only slight alterations in the procedure. Nineteen examples are given.
- Pathak, Ashish K.,Pathak, Vibha,Seitz, Lainne E.,Tiwari, Kamal N.,Akhtar, Mohammad S.,Reynolds, Robert C
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p. 7755 - 7757
(2007/10/03)
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- Synthesis of 5'-thioalkyl, sulfoxide and sulfone pyrimidine nucleosides
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The preparation of 5'-thioalkyl, sulfoxide and sulfone pyrimidine nucleosides is [4-11] is described. The key steps of this synthesis are the nucleophilic displacements of a chlorine by a thioalkyl sodium salt or the direct introduction of the thioalkyl group under Mitsunobu conditions.
- Agrofoglio,Girard,Fleury,Leonce
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p. 599 - 600
(2007/10/03)
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- A mild and efficient method for the deprotection of tert-butyldimethylsilyl ethers using iodine in methanol
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An effective method for the cleavage of tert-butyldimethylsilyl ethers using a 1% solution of iodine in methanol is described.
- Vaino, Andrew R.,Szarek, Walter A.
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p. 2351 - 2352
(2007/10/03)
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- Nucleoside Sultones: Synthons for the Preparation of Novel Nucleotide Analogues. 1. Synthesis and Ring-Opening Reactions
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Treatment of either the 5'-O-tosyl or the 5'-O-mesyl derivative of 3'-O-mesylthymidine with lithium acetylide-ethylenediamine complex in DMSO affords the intramolecular 6,3-ester of 1,2,5,6-tetradeoxy-1-(3,4-dihydro-5-methyl-2,4-dioxo-1(2H)-pyrimidinyl)-β-D-erythro-hexofuranuronosulfonic acid (2).Similarly, the 5'-O-tosyl or 5'-O-mesyl derivative of 1-(2-deoxy-3-O-mesyl-β-D-threo-pentofuranosyl)thymine affords the intramolecular 6,3-ester of 1,2,5,6-tetradeoxy-1-(3,4-dihydro-5-methyl-2,4-dioxo-1(2H)-pyrimidinyl)-β-D-threo-hexofuranuronosulfonic acid (5).Sultone 5 reacts with a variety of nucleophiles to afford good yields of the corresponding 3'-substituted sulfonate salts (6, 7, 9, and 10) and, in some cases, the unsaturated nucleoside 8.Sultone 2 was generally much less susceptible to ring opening by nucleophiles.However, in the presence of base, nucleophilic substitution with azide ion did proceed via the intermediate anhydronucleoside, 11, to afford 6.Reaction of 2 with EtOH-NaOH afforded a 1:1 mixture of the epimeric 3'-hydroxy compounds 9 and 12.The above sulfonate salts represent interesting new isosteres of nucleoside 5'-O-phosphates.
- Crooks, Peter A.,Reynolds, Robert C.,Maddry, Joseph A.,Rathore, Anita,Akhtar, M. Shamim,et al.
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p. 2830 - 2835
(2007/10/02)
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