| Cross Linker (DVB): | 1% |
| Particle Size (mesh): | 100-200 |
| Loading (mmol/g): | 0.5-1.5 |
| Hydroxymethyl resin is ideal for the solid phase immobilization of carboxylic acid. Less cross-linking is observed than that with Merrifield resin during the attachment of diacids [1]. Reaction with a suitable phosgene equivalent converts this resin to a support suitable for the immobilization of amines [2]. The carbamate linker of hydroxymethyl polystyrene can be used as an equivalent of Cbz, is stable to a wide range of acidic, basic and reductive conditions. Fisher indole synthesis and Pictet-Spengler cyclization on solid support, which require 70ºC in acetic acid with zinc chloride and 10% TFA in dichloromethane, respectively, were successfully carried out using this linker [3]. Methyl esters can be produced by transesterification with MeONa [4] or Ti(OEt)4/C2H5CO2Me [5]. Carboxamides are also accessible via Lewis acid catalyzed aminolysis [6]. Highly pure ketopiperazines can be produced by the resin-bound alpha-amino acids [7]. References [1] J. M. Goldwasser, et al., Can. J. Chem., 1978, 56, 1562 [2] D. J. Burdick, et al., Tetrahedron Lett., 1993, 34, 2589 [3] L. H. Yang, et al., Tetrahedron Lett., 2000, 41, 6981 [4] R. Frenette, et al., Tetrahedron Lett., 1994, 35, 9177 [5] L. T. Tietze & A.Steinmetz, Angew. Chem. Int. Ed. Engl., 1996, 35, 651 [6] D. R. Barn, et al., Tetrahedron Lett., 1996, 37, 3213 [7] C. Hulme, et al., Tetrahedron Lett., 2000, 41, 1509 |
|
