We have found that boron trifluoride-methanol complex (BTMC) is an effective non-depurinating detritylating agent in automated DNA synthesis. Dichloroacetic acid (DCA) is at present widely used for the deprotection of the 5'-hydroxyl group prior to coupling the next nucleotide (1); however, the protected purine bases, 6'-isobutyryl-2'-deoxyguanosine and 4'-benzoyl-2'-deoxyadenosine, are unstabl...

Reaction conditions for the CC cross-coupling of O(6)-alkyl-2-bromo- and 2-chloroinosine derivatives with aryl-, hetaryl-, and alkylboronic acids were studied. Optimization experiments with silyl-protected 2-bromo-O(6)-methylinosine led to the identification of [PdCl(2)(dcpf)]/K(3)PO(4) in 1,4-dioxane as the best conditions for these reactions (dcpf=1,1'-bis(dicyclohexylphosphino)ferrocene). A...

The deprotection step is crucial in order to secure a good quality product in Fmoc solid phase peptide synthesis. 9-Fluorenylmethoxycarbonyl (Fmoc) removal is achieved by a two-step mechanism reaction favored by the use of cyclic secondary amines; however, the efficiency of the reaction could be affected by side reactions and by-product formation. Several aspects have to be taken into considera...

A monodisperse, spherical mesoporous silica (Acid-Prepared Mesoporous Spheres, APMS) was prepared and then functionalized with two types of Fmoc (9-fluorenylmethyloxycarbonyl) terminated silanes with variable chain lengths. N2 physisorption experiments indicated that, under some conditions, the pores of the solid were completely filled by the Fmoc-protected organosilanes. These blocked pores we...

Treatment of the 5′-carboxaldehyde derived by Moffatt oxidation of 6-N-benzoyl-2′,3′-Oisopropylideneadenosine (1) with the “(bromofluoromethylene)triphenylphosphorane” reagent and deprotection gave 9-(6-bromo-5,6-dideoxy-6-fluoro-â-D-ribo-hex-5-enofuranosyl)adenine (4). Parallel treatment with a “dibromomethylene Wittig reagent” and deprotection gave 9-(6,6dibromo-5,6-dideoxy-â-D-ribo-hex-5-eno...

Photogenerated acid (PGA) was used as the acid to remove the protection group from amino acids or peptide oligomers. Comparative study of the deprotection using a PGA, trisarylsulfonium antimonyhexafluoride (SSb), and trifluoroacetic acid (TFA) was performed on glass microscope slides. The results showed that PGA can replace TFA in the deprotection step of oligopeptide synthesis with comparable...

Use of a bis-dithiane deprotection-tandem bis-spiroacetalisation sequence was key to the successful synthesis of the [5,6,6]-bis-spiroacetal of the antimitotic agent spirastrellolide B, achieved in a highly convergent fashion involving successive dithiane alkylations.

A heterometallic lanthanide complex has been prepared by sequential deprotection and complexation of an orthogonally protected ligand: luminescence and NMR spectroscopy have been used to probe the integrity of the complex.

A concise synthetic route has been developed for the preparation of a constrained peptidomimetic pyrazinone building block. From hydroxy-L-lysine, the desired pyrazinone is obtained in 43% overall yield (6 steps) via an efficient deprotection-double cyclization sequence.

Synthesis of 5''-phosphate 2'-O-ribosylribonucleosides [Nr(p)] of four common ribonucleosides, and 3'-phosphoramidites of 5''-phosphate 2'-O-ribosyladenosine and 2'-O-ribosylguanosine using the H-phosphonate chemistry is described. An additional ring protected by benzoyl groups was incorporated into the main ribosyl ring in the reaction with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose in th...