PS-carbodiimide

Proline analogs, biaryl-substituted, fluorous synthesis 112 PS-anthracene, dienophiles 151 PS-carbodiimide 136 Pimine C-2, nucleophilic displacement 119... 

The earliest published example of microwave-assisted SPOS involved diisopropyl-carbodiimide (DlC)-mediated solid-phase peptide couplings [24], Numerous Fmoc-protected amino acids and peptide fragments were coupled with glycine-preloaded polystyrene Wang resin (PS-Wang) in DMF, using either the symmetric anhydride or preformed N-hydroxybenzotriazole active esters (HOBt) as precursors (Scheme 12.1). 

In the late 1980s, Wynn and Malkin and Hippier, Ratajczak and Haehnel ° independently prepared a cross-linked adduct between the PS-I reaction-center complex and PC using the water-soluble, cross-linking agent A-ethyl-3[3-(dimethylamino)propyl]carbodiimide (EDC) in a search for evidence ofthe involvement of PsaF in electron transfer between PC and PS I. Examining the adduct with SDS-PAGE, both laboratories found no evidence for the 19-kDa PsaF subunit but instead a new 31-kDa... 

Polystyrene-supported tethered l-ethyl-3-(3-dimethylamino-propyl)carbodiimide hydrochloride (PS-EDC or PS-EDCI, 11) is also a commercially available, frequently used resin-supported carbodiimide [25], which is highly effective in the coupling of carboxylic acids and amines, in the absence of any additive the use of chloroform as solvent is essential. 

Scheme 7.5 Amidation reactions using the polymeric carbodiimide PS-EDC (11).

Miller, M.M. and Boger, D.S. (2005) Polystyrene-1-ethyl-3-(3 -dimethylaminopropanej-carbodiimide Hydrochloride (PS-EDCI), in Handbook of Reagents for Organic Synthesis, Reagents for Glycoside, Nucleotide and Peptide Synthesis (ed. D. Crich), John Wiley Sons Ltd, Chichester, pp. 529-33. 

Oxygen-evolving PS II complexes which lack LHC II but still retain the three extrinsic proteins were prepared with 2.2% HTG from spinach PS II membranes [8,11]. The complexes were suspended in 40 mM Mes-NaOH (pH 6.5), 5 mM MgCl2, 10 mM NaCl and 0.4 M sucrose and stored at 77 K. A zero-length crosslinker, l-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and succinimidyl esters with different chain lengths (disuccinimidyl-succinate, -adipate, -suberate and -sebacate which are called here DS 2, DS 4, DS 6 and DS 8, respectively) were used. For crosslinking, 15 jul of water solution of EDC (3 mg/ml) or 5 ul of dimethylsulfoxide solution of each disuccinimidyl ester (5 mg/ml) was added to 30-45 1 of sample suspensions containing 15-30 jig chlorophyll. After the mixture was incubated at room temperature for 10 min, the crosslinked complexes were treated with 8 M urea, 10% SDS and 2% 2-mercaptoethanol for 30 min at room temperature and applied to... 

Cells of Scenedesmus obliauus (wild type) were grown heterotrophically in the dark. PS II membranes were prepared as described in [7]. The following proteases were used to modify the PS II membranes carboxypeptidase A, 1 h incubation with 1 2 Chhenzyme subtilisin Carlsberg, 30 min incubation with 20 1 Chhenzyme and trypsin, 10 min incubation with 50 1 Chhenzyme. Incubation with trypsin was performed at pH 7.4, otherwise all treatments were done at pH 6.5. The reactions were stopped by 20 times dilution with ice-cold 20 mM MES-NaOH pH 6.5, 20 mM NaCl, 400 mM sucrose, and 1 mM phenylmethylsulfonyl fluoride (PMSF), except for carboxypeptidase A incubations where 4 mM 1,10-phrenanthroline was substituted for PMSF. Mn depletion of PS II membranes was accomplished by a 30 min incubation with either 0.8 M Tris-HCl pH 8.4 or 5 mM NHjOH pH 6.5. Histidine and carboxyl residues in PS II membranes were modified with 500 /xM diethylpyrocarbonate (DEPC) [8] or 10 mM l-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) [9], respectively. More details regarding these procedures can be found in [5]. 

Polycarbonate blends with polyQactic acid) have been compatibilized through addition of bis(isocyanate), bis(carbodiimide), oxazoUne-f-PS, or epoxy resin (Wang et al. 2012e Mukawa et al. 2011). 

Batch instruments are generally compatible with both Fmoc//Bu and Bck/ Bzl methods as well as polystyrene, polyethylene glycol-polystyrene graft (PEG-PS). and polyethylene oxide-polystyrene (PEO-PS) supports (for recent reviews see refs 31 and 32). For amino acid activation, protocols have been developed to include carbodiimide, aminium and phosphonium salts, and active esters (pcntafluorophenyl esters and acid halides). For batch instruments designed to monitor the Fmoc function, UV or conductivity detectors are used. 

Vovk MV, Lebed PS, Chemega AN, Pirozhenko VV (2004) Unusual cyclization of N-(l-Aryl-l-chloro-2,2,2-trifluoroethyl)-N -(p-tolyl)-carbodiimides in the presence of trieth-ylamine. Russ J Org Chem 40 195-198... 

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