Biomedical subjects

Jeffrey S Link

Publications and source records attributed to Jeffrey S Link.

4 recordsLinked to original sources

PubMed2005

Trimethylsilyl-directed 1,3-dipolar cycloaddition reactions in the solid-phase synthesis of 1,2,3-triazoles.

[reaction: see text] A regioselective method for the preparation of 1,5-trisubstituted 1H-1,2,3-triazoles via a 1,3-dipolar cycloaddition of 1-trimethylsilylacetylenes with organoazides is described. Immobilization of the azide on REM resin and subsequent cycloaddition afforded a 2 x 2 x 4 x 3 membered 1,5-disubstituted 1H-1,2,3-triazole library with an average purified yield of 68%.

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PubMed2003

2-azabicyclo[2.2.2]octa-3,5-dione via a nitrile Diels-Alder reaction.

The hetero-Diels-Alder reaction of an electron-deficient nitrile, p-toluenesulfonyl cyanide, with the silyl enol ether of cyclohexenone produced a hydrolytically sensitive [4 + 2] adduct in good yield. Use of Mander's reagent, ethyl cyanoformate, with the same diene, produced an unstable adduct. Hydrolysis of the tosyl cyanide adduct resulted in the isoquinuclidinone 2-aza[2.2.2]octa-3,5-dione as a crystalline compound in excellent yield from the nitrile.

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PubMed2003

Oxa-di-pi-methane photochemical rearrangement of quinuclidinones. Synthesis of pyrrolizidinones.

[reaction: see text] The oxa-di-pi-methane (ODPM) photochemical rearrangement, a triplet-sensitized sigmatropic 1,2-acyl shift of beta,gamma-enones, was successful utilizing methyl and heptyl 1-aza-3-carboalkoxybicyclo[2.2.2]oct-2-en-5-ones (quinuclidinones) as the photoprecursors. The cyclopropane of the heptyl ester tricyclic photoproduct could be opened with lithium dimethylcuprate or via hydrogenolysis to produce the corresponding pyrrolizidinone skeletons.

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PubMed2003

Alternative solvents for elevated-temperature solid-phase parallel synthesis. Application to thionation of amides.

A new class of higher-boiling solvents was investigated for elevated-temperature solid-phase parallel synthesis. Extremely low vapor pressures at high temperature and a broader range of solvent effect tuning make this new class of solvents an ideal choice for high-temperature parallel solid-phase synthesis. Benzyl benzoate is identified as a superior high-boiling solvent for parallel solid-phase Lawesson's thionation reactions.

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