N O O O H H H O 1 × 2 CH 2 O H H H O 10 × 1 H 2 C N Et SO 2 (CF 2 ) 3–7 CF 3 N O O O HC O H 2 C HC O OCH 2 CH 2 NEtSO 2 (CF 2 ) 3–7 CF 3 H 2 C 1 10 AlBN NH(CH 2 ) 6 NHCO HC O H 2 C HC O OCH 2 CH 2 NEtSO 2 (CF 2 ) 3–7 CF 3 H 2 C N N NMe 2 NH(CH 2 ) 6 NHCO HC O H 2 C HC O OCH 2 CH 2 NEtSO 2 (CF 2 ) 3–7 CF 3 H 2 C N N NMe 2 H 1 10 1 10 NMe 2 N N O NH(CH 2 ) 6 NH 2 5 3 acid base 4 5-H + 3 + A soluble fluorous phase polymer support David E. Bergbreiter* and Justine G. Franchina Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA The synthesis of fluorous phase soluble fluoropolymer supports that readily covalently bind amine-containing reagents and that react with and separate from reagents in aqueous and hydrocarbon solvents is described. Fluorous phase chemistry is the most recent of several strategies that have been developed to facilitate separation of catalysts or reagents from products or one another. 1–5 Such separation processes are of increasing interest for environmental reasons and as a basis for the recovery, separation and processing of intermediates or products in synthetic chemistry. 2,6 As origi- nally described by Horv´ ath, 1 this chemistry consists of essentially three elements; a fluorocarbon solvent, a hydro- carbon solvent and a fluorous tag that renders something fluorous phase soluble. Here we describe an alternative approach to synthesis of fluorous labels. The idea was to prepare a soluble fluorocarbon polymer that has reactive sites that can be used to covalently bind reagents and to render them soluble in the fluorous phase as a polymer-bound reagent. A soluble polymer support for fluorous phase chemistry has several requirements beyond those generally expected in a polymer support. Such a polymer should be selectively soluble in a fluorous phase as opposed to an aqueous or hydrocarbon solvent phase. It should be easy to attach or remove reagents, catalysts or ligands. Moreover, if a fluoropolymer support were to be practically useful, emulsions formed by shaking a hydrocarbon solution with the fluoropolymer in the fluorous phase should quickly and easily phase separate. Finally, a fluorous phase soluble fluoropolymer supported reagent has to react readily with species in a non-fluorocarbon aqueous or hydrocarbon phase. The preliminary experiments outlined here show that these goals can be achieved with simple fluorocarbon polymers derived from acrylic acid. To test our ideas, we prepared a fluoropolymer-bound dye as shown in Scheme 1. The requisite fluoropolymer-bound dye is prepared in two steps. First, we prepared a fluoroacrylate– N-acryloyloxysuccinimide (NASI) copolymer 3. The active ester in this copolymer was in turn used to attach an amino- containing p-Methyl Red derivative 4 to yield a highly coloured pH-sensitive fluoropolymer-bound dye 5. The copolymerization of the fluorinated acrylate 1 and the N-acryloyloxysuccinimide 2 was accomplished using AIBN as the initiator in tert-butyl alcohol. After 48 h, the copolymer precipitated. After decantation of the remaining reaction solution, any residual monomers in the fluoropolymer were removed by THF extraction. The product was characterized by IR spectroscopy (imide peaks at 1818 and 1788 cm 21 , an intense but broad carbonyl peak at 1746 cm 21 and C–F peaks in the 1150–1250 cm 21 region). The absence of vinyl peaks at d 5.8–6.8 in the 1 H NMR spectrum of the polymer confirmed that there was no monomer in the polymeric product. The polymer’s molecular weight was measured by end group titration for samples of the homopolymer of 1 and for 1–NASI copolymers produced using 4,4A-azobis(4-cyanovaleric acid) as the initiator. These M n values were 120 345 and 107 705 Da, respectively. Viscometry was also carried out and the intrinsic viscosity of the 1–NASI copolymer produced with AIBN initiation was 1.56 dl g 21 in Cl 2 CFCClF 2 at 29 °C (K and a values for this polymer are not available) (a structurally similar fluorinated polyacrylate of reasonably high molecular weight had a reported intrinsic viscosity of 0.25–0.49 dl g 21 ). 7 Scheme 1 Chem. Commun., 1997 1531 Published on 01 January 1997. Downloaded on 29/10/2014 17:50:16. View Article Online / Journal Homepage / Table of Contents for this issue