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Resin cleavage

A protocol for microwave-assisted acid-mediated resin cleavage has been presented by Stadler and Kappe [28]. Several resin-bound carboxylic acids (see Scheme 7.8) were cleaved from traditionally non-acid-sensitive Merrifield resin by... [Pg.326]

In addition to the aforementioned microwave-assisted reactions on solid supports, several publications also describe microwave-assisted resin cleavage. In this context it has been demonstrated that carboxylic acids could be cleaved from conventional Merrifield resin, using the standard TFA-DCM 1 1 mixture, by exposure of the polymer-bound ester and the cleavage reagent to microwave irradiation in a dedicated Teflon autoclave (multimode instrument). After 30 min at 120 °C, complete recovery of the carboxylic acid was achieved (Scheme 12.9) [26]. At room temperature, however, virtually no cleavage was detected after 2 h in 1 1 TFA-DCM. [Pg.413]

The resin-bound trienes 83 (Scheme 11) were prepared in a similar fashion to the solution-phase studies (Sect. 2.2.2) and underwent tandem RCM resin-cleavage to liberate four macrolactones 84a,b and 85a,b in a combined yield of 52%. Although, as expected, a large amount of initiator 3 was required to effect this transformation, the procedure constituted a novel and efficient route to the epothilones which paved the way for the generation of a library of epothilone analogs. The library synthesis was achieved using the recently developed SMAR-I9 microreactors (SMART=single or multiple addressable radiofrequency tag) [25] (Scheme 12). [Pg.98]

Each microreactor consists of a polymer-bound substrate and a radiofrequency encoded microchip enclosed within a small porous vessel. The radiofrequency tag allows the identity of the substrate contained within each microreactor to be established readily. Using this technology, the polymer-bound substrates 86 were individually elaborated, within separate microreactors, by sequential reactions with acids 87 and alcohols 88 in a similar way to the solution-phase processes [25c]. Each of the microreactors was then subjected to the tandem RCM resin-cleavage conditions employing initiator 3. The products from each microreactor were obtained as a mixture of four compounds (89-92). The library of analogs prepared by this technique was then screened for biological activity [25c]. [Pg.98]

The Larock indole synthesis was adapted to the solid phase both for the synthesis of 1,2,3-trisubstituted indole-5-carboxamides [396] and, as illustrated, for the "traceless" synthesis of 2,3-disubstituted indoles 308 [397], As seen earlier, the trimethylsilyl group is fastened to C-2 with complete regioselectivity. The TMS group is cleaved under the resin cleavage conditions. The original Larock conditions were not particularly successful. [Pg.144]

The advantages of this approach are the opportunity to purify the intermediate S-protected derivatives, the introduction of the disulfide bonds in the early stages of the synthesis/62 and also a one-pot deprotection/resin cleavage/oxidation method/63-65 The main reagents used for this purpose are summarized in Table 2. [Pg.106]

Peptide Protein Phase Resin Cleavage Methyl Cleavage Ref... [Pg.380]

Peptide Protein Coupling Resin Resin Cleavage +Methyl Oeavage Ref... [Pg.380]

Amino Add Coupling Method Resin Cleavage Step Peptide Yielda (%) Ref... [Pg.443]

The majority of cyclic peptides synthesized on solid support are cyclized in the head-to-side-chain or side-chain-to-side-chain mode. For this purpose the amino acids involved in cyclization must be side-chain protected in a manner that allows for an additional level of orthogonal deprotection. Thus, upon assembly of the fully protected linear precursor on-resin, deprotection of the functionalities involved in the lactam ring formation is performed, followed by regio-selective cyclization by amide bond formation, and finally by the resin-cleavage/deprotection step as outlined in Scheme 16. In Table 8, examples of syntheses of such cyclic peptides are listed with the relevant information regarding protection scheme, resin anchor, and mode of cyclization. [Pg.491]

Loaded resin Cleavage conditions Product, yield (purity) Ref. [Pg.49]


See other pages where Resin cleavage is mentioned: [Pg.197]    [Pg.31]    [Pg.327]    [Pg.413]    [Pg.167]    [Pg.158]    [Pg.158]    [Pg.270]    [Pg.65]    [Pg.218]    [Pg.335]    [Pg.338]    [Pg.342]    [Pg.384]    [Pg.399]    [Pg.447]    [Pg.450]    [Pg.484]    [Pg.488]    [Pg.199]    [Pg.322]    [Pg.322]    [Pg.18]    [Pg.258]    [Pg.260]    [Pg.120]   
See also in sourсe #XX -- [ Pg.326 ]

See also in sourсe #XX -- [ Pg.413 ]

See also in sourсe #XX -- [ Pg.18 ]

See also in sourсe #XX -- [ Pg.18 ]




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Cleavage protocols, peptide-resin mixture

Microwave resin cleavage

Peptides, resin-bound, cleavage

Preparing the resin for cleavage

Protected peptide fragments cleavage from resin

Resin cleavage metathesis

Resin cleavage photochemical

Resin cleavage using DIBAL

Resins peptide cleavage from

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