Ester Resin Research Articles

SYNTHESIS OF THE MERRIFIELD RESIN ESTERS OF N-PROTECTED AMINO ACIDS WITH THE AID OF HYDROGEN BONDING1

Abstract A synthesis of the Merrifield resin esters of N-protected amino acids was attempted with the aid of hydrogen-bonding property of fluoride ion with carboxylic acids to obtain the esters in satisfactory yields. This will provide an alternatively efficient and economical method for the preparation of the key intermediate of the solid phase peptide synthesis.

The use of Nε-2-Hydroxyarylmethylene-protected ornithine and lysine derivatives in solid-phase peptide synthesis

Nα-t-Butoxycarbonyl-Nε-(2-hydroxyarylmethylene)-ornithine and -lysine have been synthesized and coupled with amino acyl resins in the presence of dicyclohexylcarbodiimide to form N-protected peptide resin esters. The ketimine protecting group was found to be stable under anhydrous conditions and the urethane blocking group could be removed preferentially. A number of lysine- and ornithine- containing peptides have been synthesized by the solid-phase technique.

A study on phenoxy-resin esters of cinnamylideneacetic acid and its derivatives

Abstract Photocrosslinkable polymers were prepared from phenoxy resin which was photoactivated by esterifying cinnamylideneacetic acid, α-cyanocinnamylideneacetic acid or cinnamylidenepyruvic acid. Relative sensitivities and spectral sensitivities of these polymers were determined by comparing with the phenoxy resin ester of cinnamic acid. It was found that the polymer which was photo-activated with cinnamylidenepyruvic acid had the highest photosensitivity and its spectral sensitivity extended up to 500 nm without the aid of any additional sensitizing dye. The mechanism of the photocrosslinking of these polymers was also considered.

A rapid method for the preparation of amino acid resin esters for Merrifield solid-phase peptide synthesis.

AbstractAn improved method for the preparation of Merrifield resin esters is presented. This method is rapid, is free of racemization, and is not complicated by a quaternization side reaction. Chloromethylated resin beads, t‐butoxycarbonyl amino acid, and potassium t‐butoxide are heated at 80 °C in dimethylsulfoxide for one‐half hour to yield resin esters of suitable substitution for solid‐phase petide synthesis. All twenty of the BOC protected common amino acids were esterified to the resin by this method. Resin substitution values lie in the range of 0.13 meq/g (BOC‐Glu (NH2)) to 0.66 meq/g (BOC/Pro), with most of the amino acids yielding 0.3–0.4 meq/g (on a resin containing 0.8 meq Cl/g).

Solid Phase Synthesis. Evidence for and Quantification of Intra res in Reactions

Abstract Intrareaction occurs between moieties attached to copolystyrene-2% divinylbenzene resin as used in solid phase synthesis even when only 0.5% of the phenyl residues are functionalized. Evidence for this interaction has been obtained from the dimeric products resulting from Dieckmann cyclization of resin bound sebacates and ω-cyanopelargonyl thiol resin esters, from kinetic and product data on radioactivity scrambling during the Dieckmann cyclization of uniquely singly labeled tertiary alkyl pimeloyl resin esters, and from anhydride formation with carboxymethyl resin. The extent to which site-site interactions can occur as a function of the percentage functionalization has been measured quantitatively by radiotracer studies on intraresin anhydride formation from carboxymethyl substituted resin. The synthesis and characterization of the resin bound re-actants is described, and the significance of these observations is discussed.

The Preparation of Merrifield‐Resins Through Total Esterification With Cesium Salts

AbstractThe reaction of chloromethylated polystyrene‐co‐1%‐divinylbenzene resin with the cesium salts of N‐protected amino acids proceeds fast and without side reactions to give N‐protected amino acyl resin esters free of quaternary ammonium sites or reactive chloride.

Improved solid phase peptide synthesis II. the reaction of an α-amino acid N-carboxyanhydride with N-trimethyl silyl amino acid non-crosslinked resin ester

Improved solid phase peptide synthesis II. the reaction of an α-amino acid N-carboxyanhydride with N-trimethyl silyl amino acid non-crosslinked resin ester

A model system for studying solid phase peptide reactions

A model system has been devised for studying solid-phase peptide reactions. The system is based on the stepwise solid-phase synthesis of l-leucyl- l-alanylglycyl- l-valine starting from BOC- l-valine resin ester. The eight possible components—valine, six shorter peptide fragments, and the tetrapeptide—of this system can be determined quantitatively with an automatic amino acid analyzer. This model system can be utilized to evaluate different resins, reagents, and reactions (racemization-free) for use in solid-phase peptide synthesis.

Synthesis and biological activity of thyrotropin-releasing hormone.

The synthesis of thyrotropin-releasing hormone (TRH) has been carried out by a simple solid-phase procedure with a high yield of a pure hormone. Beginning with L-proline resin ester, a residue of t-butyloxycarbonyl-Lhistidine was added. After deprotection, a residue of L-pyroglutamic acid was added. All peptidebond forming steps were conducted by the activation of the carboxyl group of the entering amino acid through the formation of its mixed anhydride with isobutylchloroformate. Cleavage of the completed peptide from the resin was accomplished by two 30-min exposures of the resin to gaseous HBr while the resin was suspended in trifluoroacetic acid. The free carboxyl group of peptide-bound proline was quantitatively converted to the amide by treating the mixed anhydride of the tripeptide and isobutylformate with anhydrous ammonia. Bioassay of this material for thyrotropin-releasing activity in mice showed it to be active at doses as low as 2 ng/mouse. The oral to iv ratio of the dose required for activit...

Viscoelastic Properties of Oil-Modified Phenolic Resin

The chemorheological study of rubbers was developed by A.V. Tobolsky by means of chemical stress relaxation measurement. We should also propose a different method by means of dynamic-mechanical measurement on chemorheological study for the same purpose as he has conceived, i.e., investigate both the cross linking and the scission reactions of thermosetting type of polymers.For the investigation of the cross linking and the scission reactions two types of coating films were used here as shown in Table I, Chinese tung oil-modified phenolic resin and epoxy resin ester for comparison with it.Dynamic modulus E1 of the samples used here has been exhibited rubbery plateau at the higher temperature ranges, where the values of dynamic modulus E1 are indepedent on the frequencies of measurement, as shown in Figs. 1 and 2. Time dependency of dynamic modulus E1 at the higher temperature region is shown in Fig. 3 in straight lines within shorter time ranges.Dynamic modulus E1 obtained at the plateau region is expressed by Eq. (1) according to rubber elasticity.E1=3ρRT/Mc (1)Density of cross links ν (mol/g) in polymer is expressed by Eq. (2) from Eq. (1).ν=E1/(3ρRT) (2)The slopes of the straight lines of dynamic modulus E1 at each temperature shown in Fig. 3, therefore, may correspond to the reaction-rate constant k of cross linking for the sample, respectively. As such dependence of the reaction-rate constant k on temperatures is known to be expressed by the Arrhenius Eq. (3).k=Aexp(ΔH/RT) (3)In this way the apparent activation energy ΔH of the cross linking reaction for the four samples can be calculated as shown in Table III, from replot in the form of log k vs. 1/T as shown in Fig. 4. From the break of slopes of the straight lines in Fig. 4 we can obtain two different values of ΔH for a sample. This phenomenon will be accounted for by the fact that there are two types of cross linking reactions for a sample over the temperature range used herein.In order to ascertain what kinds of cross linking reactions had taken place during the baking process we continued the chemical experiments as shown in Figs. 5, 6, 7 and 8, respectively. It is clear that there are two heat generations due to chemical reactions from the results of Differential Thermal Analysis (DTA) of the samples as shown in Fig. 5, i.e., the heat generation located in lower temperature region takes place both in air and N2 flow, whereas the higher temperature in air only. From the results shown in Figs. 6, 7 and 8, the heat generation located in lower temperature region seems to be caused by the cross linking reaction after degradation of hydroperoxide formed in the drying oil of the sample, the higher temperature may be due to another type of cross linking reaction accompanied with the degradation of drying oil.Those results of chemical experiments approximately agree with the results obtained dynamic-mechanical measurements mentioned above.

アルキド樹脂およびエポキシエステル樹脂皮膜の膨潤

アルキド樹脂およびエポキシエステル樹脂皮膜の膨潤

Copolymerization of the unsaturated Novolack resin ester with styrene

Copolymerization of the unsaturated Novolack resin ester with styrene

Tank finish based on Shell Epon resin ester is still in excellent condition after five years' exposure to Houston humidity and sun

Tank finish based on Shell Epon resin ester is still in excellent condition after five years' exposure to Houston humidity and sun

ブリキ印刷用スチレン化エポキシ樹脂の基礎的問題

ブリキ印刷用スチレン化エポキシ樹脂の基礎的問題

脱水ヒマシ油-エポキシ樹脂エステル塗料の耐熟性

脱水ヒマシ油-エポキシ樹脂エステル塗料の耐熟性

ビニル化エポキシ樹脂エステル塗料の研究 (第3報)

ビニル化エポキシ樹脂エステル塗料の研究 (第3報)

ビニル化エポキシ樹脂エステル塗料の研究 (第1報)

ビニル化エポキシ樹脂エステル塗料の研究 (第1報)

ビニル化エポキシ樹脂エステル塗料の研究 (第2報)

ビニル化エポキシ樹脂エステル塗料の研究 (第2報)