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Vol. 2, No. 8
New Nitrogen-Containing Heterocycles


Introduction / 5-Membered Heterocyclic Rings / 6-Membered Heterocyclic Rings
Mitsunaobu Reagents / Polymer-Supported Reagents / JandaJels™ / Functionalized Silica Gels

Functionalized Silica Gels

These silica-based scavengers and reagents are prepared from high-purity silica gel, making them an ideal choice for organic and combinatorial applications. They are very easy to handle, demonstrate broad solvent compatibility, and do not swell in solvents - which gives them a higher scavenging capacity for a given volume.


3-(1-PIPERAZINO)PROPYL-FUNCTIONALIZED SILICA GEL (PIPERAZINE, SILICA-SUPPORTED)

A useful deblocking and scavenging agent for Fmoc and for the Bsmoc amino protecting group. Also used to immobilize metal carbonyl complexes, for the synthesis of 2-aminobutadienes, as a traceless linker in a cross-coupling strategy starting with diazonium ions, and as a solid-phase Knoevenagel catalyst.

55,260-7   5g; 25g; 100g


PYRIDINIUM CHLOROCHROMATE ca. 20% ON SILICA GEL 200-400 MESH (PCC ON SILICA)

Used for the general oxidation of alcohols to carbonyl compounds, selective oxidation of allylic and benzylic alcohols, organometallic oxidation, oxidative transpositions, oxidative cleavages, and oxidative cyclizations. PCC on silica provides anhydrous conditions that may otherwise promote side reactions and reduce yields. It greatly facilitates removal of polymeric reduced chromium by-products, and is compatible with acid-sensitive protecting groups.

56,980-1   25g; 100g


PYRIDINIUM DICHROMATE ca. 20% ON SILICA GEL (PDC ON SILICA)

Used as an alternative to PCC in nucleoside and carbohydrate oxidation, particularly for fragile molecules. Can also be used in conjunction with tert-butyl hydroperoxide for oxidative transformations. A very convenient and effective reagent for oxidizing allylic and benzylic alcohols, as well as saturated primary and secondary alcohols and it is compatible with acid-sensitive groups, such as cyclopropanes, or ketals.

56,982-8   25g; 100g


3-(1-PIPERIDINO)PROPYL, FUNCTIONALIZED SILICA GEL (PIPERIDINE, SILICA-SUPPORTED)

Used as an immobilized catalyst for Knoevenagel condensation, and for selective monoglyceride synthesis. May also be used as a tertiary-bound amine for scavenging acids, thereby avoiding salt elimination problems.

56,984-4   5g; 25g; 100g


3-(4,4-TRIMETHYLENEDIPIPERIDINO)PROPYL, FUNCTIONALIZED SILICA GEL

Used as a deblocking-scavenging agent for Fmoc amino-protecting. It is a better deblocking agent than the piperazino gel, but less efficient for scavenging dibenzofulvene. Can be used in conjunction with the piperazino gel for enhanced performance. May also be used as an electrophile scavenger or a silica-bound base.

56,985-2   25g; 100g


3-(1,3,4,6,7,8,-HEXAHYDRO-2H-PYRIMIDO-[1,2-A] PYRIMIDO)PROPYL, FUNCTIONALIZED SILICA GEL (TBD ON SILICA)

This grafted hindered strong base has been used as a basic catalyst in Michael reactions, Knoevenagel condensations, Robinson annulations, and nucleophilic epoxidations.

56,986-0   5g; 25g; 100g


3-(MALEIMIDO)PROPYL, FUNCTIONALIZED SILICA GEL (MALEIMIDO, SILICA-SUPPORTED)

A functionalized silica gel designed to scavenge thiols.

56,990-9   5g; 25g