ArgoGels

Hallman and Moberg described the preparation of a chiral bis(oxazoline) grafted on ArgoGel [120] (87, in Scheme 48). In the zinc-catalyzed Diels-Alder reaction, polymer 87 was found to be less active than the analogous... 

A combination of a multicomponent Ugi transformation and an intramolecular Diels-Alder reaction has been developed by Paulvannan [13]. Hence, condensation of the resin-bound (acid-labile ArgoGel-Rink resin) amine 10-37 with a tenfold... 

In another example, a polymer-supported chromium porphyrin complex was supported on ArgoGel Cl and then employed for the ring-opening polymerization of 1,2-cyclohexene oxide and C02 [95], This complex showed higher activity than a C02-soluble equivalent, and the solid nature of the catalyst meant that recycling of the catalyst was much easier. 

ArgoGel-MB-CHO resin (366 mg, 0.42mmol/g substitution) was placed into an Ace pressure tube (note 5). Trimethyl orthoformate (TMOF 5 mL) was added to the flask along with the primary amine (10 equiv.). The tube was capped and heated for 2h at 70°C in a rotating oven (note 6), and cooled. The TMOF solution was removed with the use of a filtration cannula, and the entire process was repeated. The resin was washed with TMOF (5 mL, lx) and anhydrous methanol (5 mL, 3 x) Anhydrous methanol (5 mL) was added to the resin, followed by the addition of sodium borohydride (133 mg, 20 equiv.). After vigorous gas evolution had ceased, the tube was capped and agitated for 8 h at room temperature. The resin was then transferred to a polypropylene reaction vessel and washed with methanol (5mL, 3 x), methanol water (1 1, 5mL, 3 x), DMF water (1 1, 5mL, 3 x), DMF (5mL, 3 x), and methylene chloride (5 mL, 3 x). 

ArgoGel MB-CHO resin was purchased from Argonaut Technologies, substitution = 0.42 mmol/g, lot 104—20. 

Cleavage of the thiazoles from ArgoGel MB-CHO resin required longer cleavage times (4h) and modest heating... 

Scheme 1.1 Attachment of a pyridyl ligand and (1) to ArgoGel resin (2).

Scheme 19 Synthesis of thiol containing 2,5-DKP s for use in MMP inhibition. Solid support was done using TentaGel S OH or ArgoGel-OH. (Trt = triphenyhnethyl, TES = triethylsilane). Two representative 3D conformations of 119A (blue) and 119B (cyan). Yield shown represents yield over all steps...

Fig. 10. 400 MHz H HRMAS NMR spectra of ArgoGel resin swollen with 92% CDCl3/8% CD3OD. The macrocycle, stylized as a ring, reversibly threads onto the polyethyleneglycol chain in a scheme depicted on the left. This is evident in the spectra to the right, where the upper unsplit spectrum was obtained in the absence of the macrocycle, and the lower was obtained after addition of the macrocycle. Reproduced with permission from Ref. 102. Copyright 2001 Wiley-YCH.

In this scheme, Fmoc -/ -alanine is coupled to ArgoGel-Wang resin using standard methodology to give resin 1, and then the Fmoc group is... 

In Scheme 51, an example for the immobilization of the germanium-based precursor 100 to Argogel polymer is shown208. The clean release of several biaryl compounds from the polymer 101 was achieved by electrophilic degermylation with various reagents (i-iv) (Scheme 51). 

SCHEME 51. Immobilization of 4-methoxybiphenyl to Argogel and release of the products by electrophilic degermylation... 

Fig. 1. Branched supports - lysine branched TentaGel l, high-load PEG-PS 2 and ArgoGel 3.

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