Tert-butyl Ester Groups Research Articles

Assessment of Conjugation Pathways in N-Methylporphyrins that Are Fused to Acenaphthylene, Phenanthrene, or Pyrene: Evidence for the Presence of Alternative Aromatic Circuits.

Acenaphtho-, phenanthro-, and pyrenopyrrole esters, readily available from Barton-Zard reactions of ethyl isocyanoacetate with nitroarenes, were reacted with methyl iodide and KOH in DMSO to give N-methylpyrroles and subsequent cleavage of the ester moieties was accomplished with KOH in ethylene glycol at 200 °C. Condensation with two equiv of an acetoxymethylpyrrole in refluxing acetic acid-2-propanol afforded a series of annulated tripyrranes. Cleavage of the terminal tert-butyl ester groups with trifluoroacetic acid, followed by condensation with a diformylpyrrole and oxidation with FeCl3, gave N-methyl acenaphtho-, phenanthro-, and pyrenoporphyrins. The N-methyl substituent effectively freezes the tautomeric equilibria to maximize interactions between the porphyrin nucleus and the fused aromatic substructures. Analysis of the proton NMR spectra provides evidence of the presence of extended aromatic circuits within these structures. Anisotropy of induced ring current (AICD) plots clearly shows the presence of 30π electron pathways in phenanthro- and pyrenoporphyrins that run around the exterior of the benzenoid fragments. These results demonstrate that N-alkylation can be used to relocate aromatic pathways in porphyrinoid systems.

Size Control and Biological Properties of PAMAM-Cored Multiarm Block Copolymers.

Size is one of the crucial factors influencing the biological properties of nanomedicines. However, the size control of nanomaterials is still very challenging, and the size effect on their biological properties is worth studying. Herein, we present the synthesis and size control of a series of multiarm block copolymers with the third-generation PAMAM (G3 PAMAM) as the core. The multiarm copolymers were synthesized by the ring-opening polymerization of N-carboxyanhydride of the l-glutamic acid-5-tert-butylester [Glu(OtBu)-NCA] monomer with the amine-terminated PAMAM as the initiator, followed by the synthesis of the poly(carboxybetaine) (PCB) block via the atom transfer radical polymerization of the 2-(dimethylamino)ethyl methacrylate monomer, the reaction with tert-butyl bromoacetate, and the deprotection of the tert-butyl ester groups. The polyglutamic acid (PGA) block provided abundant reactive groups for the functionalization of the multiarm block copolymers, and the PCB block imparted excellent water solubility and anti-protein adsorption capability. We synthesized three multiarm copolymers with diameters of 15, 24, and 41 nm, respectively, by tuning the polymerization degrees of the arms. Doxorubicin was coupled to the PGA block through the acylhydrazone linkage, which resulted in a pH-sensitive drug release and a drug loading of over 20%. We systematically investigated the size effects on their cellular uptake, cytotoxicity, endocytic pathway, biodistribution, tumor penetration, and antitumor activity. This work is helpful for the design of polymeric nano-drug carriers for tumor therapy.

Photoresists based on bisphenol A derivatives with tert-butyl ester groups for electron beam lithography

Four branched bisphenol A derivatives decorated with tert-butyl ester group (BPA-BU-n, n = 1–4) were synthesized. The number of BU groups was controlled precisely by selective hydrogenation. The good thermal resistance and film-forming performance suggested that BPA-BU-1 and BPA-BU-2 are candidates for photoresist materials. They were used as positive-tone photoresists by mixing with a proportionate photo-acid generator and base. Both BPA-BU-1 and BPA-BU-2 resists can obtain 40 nm L/S patterns. BPA-BU-1 resist exhibits higher sensitivity and contrast than that of BPA-BU-2 resist for their different substituted positions of acid labile groups in the molecule. All the results demonstrated that protected ratio and position had a significant effect on the patterning ability of BPA-BUs resists. This study will help to understand the relationship between molecular structures and lithographic performance, and provide useful guidelines for designing molecular resists.

Synthesis of Alkaline-soluble Triazine-based Poly(phenylene sulfide)s with Single/Double Pendant Carboxylic Acid Moieties and Their Application to Refractive Index Contrast Materials

Abstract The design, synthesis, and optical characterization of refractive-index-contrast (RIC) triazine-based poly(phenylene sulfide)s (PPSs) are investigated. Indeed, novel PPSs with two pendant groups, either tert-butyl (tBu) ester or carboxylic acid groups, at each monomer repeating unit (PPS-2E or PPS-2CA, respectively) were successfully synthesized. PPS-2CA showed high refractive index (n) values of 1.6964 (633 nm) and 1.6714 (940 nm) as well as high δn (increase in the n value by the deprotection of PPS-2E) values of +0.062 (633 nm) and +0.058 (940 nm).

Influence of Tail Groups during Functionalization of ZnO Nanoparticles on Binding Enthalpies and Photoluminescence.

We report on the tailoring of ZnO nanoparticle (NP) surfaces by catechol derivatives (CAT) with different functionalities: tert-butyl group (tertCAT), hydrogen (pyroCAT), aromatic ring (naphCAT), ester group (esterCAT), and nitro group (nitroCAT). The influence of electron-donating/-withdrawing properties on enthalpy of ligand binding (ΔH) was resolved and subsequently linked with optical properties. First, as confirmed by ultraviolet/visible (UV/vis) and Fourier transform infrared (FT-IR) spectroscopy results, all CAT molecules chemisorbed to ZnO NPs, independent of the distinct functionality. Interestingly, the ζ-potentials of ZnO after functionalization shifted to more negative values. Then, isothermal titration calorimetry (ITC) and a mass-based method were applied to resolve the heat release during ligand binding and the adsorption isotherm, respectively. However, both heat- and mass-based approaches alone did not fully resolve the binding enthalpy of each molecule adsorbing to the ZnO surface. This is mainly due to the fact that the Langmuir model oversimplifies the underlying adsorption mechanism, at least for some of the tested CAT molecules. Therefore, a new, fitting-free approach was developed to directly access the adsorption enthalpy per molecule during functionalization by dividing the heat release measured via ITC by the amount of bound molecules determined from the adsorption isotherm. Finally, the efficiency of quenching the visible emission caused by ligand binding was investigated by photoluminescence (PL) spectroscopy, which turned out to follow the same trend as the binding enthalpy. Thus, the functionality of ligand molecules governs the binding enthalpy to the particle surface, which in turn, at least in the current case of ZnO, is an important parameter for the quenching of visible emission. We believe that establishing such correlations is an important step toward a more general way of selecting and designing ligand molecules for surface functionalization. This allows developing strategies for tailored colloidal surfaces beyond empirically driven formulation on a case by case basis.

Modification of α-Cyclodextrin Polyrotaxanes by ATRP for Conjugating Drug and Prolonging Blood Circulation.

To enhance the water solubility of α-cyclodextrin (CD) polyrotaxanes (PRs) and achieve effective drug loading, we polymerized 2-hydroxyethyl methacrylate and 2-tert-butoxy-N-(2-(methacryloyloxy)ethyl)-N,N-dimethyl-2-oxoethanaminium successively from a α-CD-PR-based macroinitiator by a two-step ATRP followed by cleaving the tert-butyl ester groups, providing a α-CD-PR-cored multiarm copolymer. The multiarm copolymer had reactive hydroxyl pendant groups in the inner block of the arms, which were used to incorporate antitumor agent paclitaxel (PTX). The outer block of the arms was zwitterionic poly(carboxybetaine) and had high hydrophilicity and zero net electric charge in a neutral environment. This feature endowed the PTX-loaded multiarm copolymer with high water solubility and prolonged blood circulation. The blood circulation half-life of the PTX-loaded multiarm copolymer was determined to be about 7.7 h versus 18.8 ± 1.5 min of the reported blood circulation half-life of the PTX injected as commercial Taxol. The PTX-loaded multiarm copolymer was proved to be efficient in tumor accumulation and suppression.

Influence of thermocleavable functionality on organic field-effect transistor performance of small molecules

Diketopyrrolopyrrole based donor-acceptor-donor conjugated small molecules using ethylene dioxythiophene as a donor was synthesized. Electron deficient diketopyrrolopyrrole unit was substituted with thermocleavable (tert-butyl acetate) side chains. The thermal treatment of the molecules at 160°C eliminated the tert-butyl ester group results in the formation of corresponding acid. Optical and theoretical studies revealed that the molecules adopted a change in molecular arrangement after thermolysis. The conjugated small molecules possessed p-channel charge transport characteristics in organic field effect transistors. The charge carrier mobility was increased after thermolysis of tert-butyl ester group to 5.07×10−5cm2/Vs.

Metabolism of KO143, an ABCG2 inhibitor

The ATP-binding cassette sub-family G member 2 (ABCG2) plays an important role in modulating drug disposition and endobiotic homeostasis. KO143 is a potent and relatively selective ABCG2 inhibitor. We found that the metabolic stability of KO143 was very poor in human liver microsomes (HLM). Our further studies illustrated that the tert-butyl ester group in KO143 can be rapidly hydrolyzed and removed by carboxylesterase 1. This metabolic pathway was confirmed as a major pathway of KO143 metabolism in both HLM and mice. K1 is an analog of KO143 without the ester group. We found that the metabolic stability of K1 was significantly improved in HLM when compared to KO143. These data suggest that the ester group in KO143 is the major cause of the poor metabolic stability of KO143. The data from this study can be used to guide the development of KO143 analogs with better metabolic properties.

Synthesis and self-assembly behavior of POSS tethered amphiphilic polymer based on poly(caprolactone) (PCL) grafted with poly(acrylic acid) (PAA) via ROP, ATRP, and CuAAC reaction

This investigation reports the preparation and self-assembly behavior of polyhedral oligomeric silsesquioxane (POSS) containing poly(caprolactone)-graft-poly(acrylic acid) (POSS-PCL-graft-PAA) polymer. This article focuses on the self-assembly behavior of POSS tethered amphiphilic graft copolymer. In this investigation, POSS tethered alkyne functionalized polycaprolactone (PCL) was prepared by strategic ring opening polymerization (ROP) of e-caprolactone and α-propargyl-e-caprolactone using hydroxyl-terminated POSS as an initiator. Azide-terminated poly(tert-butyl acrylate) (PtBA) was grafted onto functional PCL via Cu-catalyzed azide-alkyne “click” (CuAAC) reaction. Finally, hydrolysis of the tert-butyl ester group into acid furnished the POSS tethered PCL-graft-PAA polymer. This amphiphilic graft copolymer was characterized by GPC, NMR, and FT-IR analyses and the morphology of the graft copolymer analyzed by HRTEM and FESEM analyses. On changing the graft copolymer concentration (low to high) in water, the morphology of the final graft copolymer changed from micelles to worm-like and core-shell. The structural motif of POSS plays an important role in this morphological transformation. The pH sensitivity was studied using DLS analysis as well as via release profile of rhodamine B as a model compound.

Homodiselenacalix[4]arenes: Molecules with Unique Channelled Crystal Structures

A synthetic route towards homodiselenacalix[4]arene macrocycles is presented, based on the dynamic covalent chemistry of diselenides. The calixarene inner rim is decorated with either alkoxy or tert-butyl ester groups. Single-crystal X-ray analysis of two THF solvates with methoxy and ethoxy substituents reveals the high similarity of their molecular structures and alterations on the supramolecular level. In both crystal structures, solvent channels are present and differ in both shape and capacity. Furthermore, the methoxy-substituted macrocycle undergoes a single-crystal-to-single-crystal transformation during which the molecular structure changes its conformation from 1,3-alternate (loaded with THF/water) to 1,2-alternate (apohost form). Molecular modelling techniques were applied to explore the conformational and energetic behaviour of the macrocycles.

Stable Poly(methacrylic acid) Brush Decorated Silica Nano-Particles by ARGET ATRP for Bioconjugation

The synthesis of polymer brush decorated silica nano-particles is demonstrated by activator regeneration by electron transfer atom transfer radical polymerization (ARGET ATRP) grafting of poly(tert-butyl methacrylate). ATRP initiator decorated silica nano-particles were obtained using a novel trimethylsiloxane derivatised ATRP initiator obtained by click chemistry. Comparison of de-grafted polymers with polymer obtained from a sacrificial initiator demonstrated good agreement up to 55% monomer conversion. Subsequent mild deprotection of the tert-butyl ester groups using phosphoric acid yielded highly colloidal and pH stable hydrophilic nano-particles comprising approximately 50% methacrylic acid groups. The successful bio-conjugation was achieved by immobilization of Horseradish Peroxidase to the polymer brush decorated nano-particles and the enzyme activity demonstrated in a conversion of o-phenylene diamine dihydrochloride assay.

Inhibition of radical reactions for an improved potassium tert-butoxide-promoted (11) C-methylation strategy for the synthesis of α-(11) C-methyl amino acids.

α-(11) C-Methyl amino acids are useful tools for biological imaging studies. However, a robust procedure for the labeling of amino acids has not yet been established. In this study, the (11) C-methylation of Schiff-base-activated α-amino acid derivatives has been optimized for the radiosynthesis of various α-(11) C-methyl amino acids. The benzophenone imine analog of methyl 2-amino butyrate was (11) C-methylated with [(11) C]methyl iodide following its initial deprotonation with potassium tert-butoxide (KOtBu). The use of an alternative base such as tetrabutylammonium fluoride, triethylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene did not result in the (11) C-methylated product. Furthermore, the KOtBu-promoted (11) C-methylation of the Schiff-base-activated amino acid analog was enhanced by the addition of 1,2,4,5-tetramethoxybenzene or 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and inhibited by the addition of 1,10-phenanthroline. These results suggest that inhibition of radical generation induced by KOtBu improves the α-(11) C-methylation of the Schiff-base-activated amino acids. The addition of a mixture of KOtBu and TEMPO to a solution of Schiff-base-activated amino acid ester and [(11) C]methyl iodide provided optimal results, and the tert-butyl ester and benzophenone imine groups could be readily hydrolyzed to give the desired α-(11) C-methyl amino acids with a high radiochemical conversion. This strategy could be readily applied to the synthesis of other α-(11) C-methyl amino acids.

High Sensitivity, Positive Tone, Low-k Polynorbornene Dielectrics

Permanent dielectric materials are necessary in microelectronic devices to separate electronic components. Low dielectric constant (low-k) materials mechanically and electrically isolate on-chip, chip-to-chip, chip-to-package, or on-package interconnections.1 Polymers are widely used for these purposes, as they offer a low stress, easily processed alternative to inorganic materials. Additionally, permanent low-k polymeric materials can often be formulated to be directly patternable by photolithography. Currently, most positive tone, permanent dielectrics utilize the diazonaphthoquinone-based photochemistry, which provides relatively low sensitivity (D100 > 300 mJ/cm2) and low contrast (< 2.5).2,3 In order to pattern very thick films or high aspect ratio structures, materials with greatly improved lithographic properties are needed. This can be accomplished with a photochemistry known as chemical amplification.4 In this case, a photo-generated acid catalyzes a deprotection reaction. This deprotection increases the solubility of the film in aqueous base developer, providing the photo-definability. The low loading of the photoactive compound provides high sensitivity and high contrast films. However, cross-linking of these positive tone films after patterning is also desirable, and the presence of the strong acid makes cross-linking difficult. To this end, our lab has previously reported a polymer chemistry that is chemically amplified and cross-linkable.5 The proof of concept polymer was synthesized as a random copolymer of tert-butyl methacrylate and 2-hydroxyethyl methacrylate. In this case, the pendent tert-butyl group is deprotected by the photogenerated acid to produce a carboxylic acid. This deprotection makes the film soluble in aqueous base developer, whereas the unexposed film is insoluble. Formulations of 1 and 3 parts per hundred photoacid generator were measured to have contrasts of 12.7 and 5.2, respectively, and sensitivities D100 of 50.2 and 32.2 mJ/cm2, respectively. These films could then be cross-linked via a Fischer esterification between the pendent carboxylic acid and the pendent alcohol in the presence of acid. The esterification cross-linking reaction is much slower than the deprotection reaction, so it did not interfere with photo-patterning. Cross-linking was proven by changes in residual stress and solubility. The results of this polymer are promising, but polymethacrylates are not appropriate for many permanent, low-k dielectric applications. A polymer with similar lithographic and cross-linking functionality is desired, which has higher glass transition and decomposition temperatures. To achieve this, a polymer with a polynorbornene (PNB) backbone has been synthesized with similar pendent functional groups. These polymers are patternable and cross-linkable by similar mechanisms to the polymethacrylate dielectric. The PNB polymer was synthesized with similar tert-butyl ester and alcohol pendent groups. The D100 of and contrast of the PNB were found to be 41.1 mJ/cm2and 12.4, respectively, which are comparable to the values measured for polymethacrylate. The PNB, however, exhibits a large difference in solubility in developer. To quantify this, dissolution characteristics of these films will be evaluated by quartz crystal microbalance analysis. Initial mechanical and electrical property measurements will be presented. Finally, the challenges associated with this chemistry will be addressed in an effort to formulate a robust dielectric with improved lithographic, mechanical, and electrical properties.

Synthesis of steroidal dendrimers modified by ‘click’ chemistry with PAMAM dendrons as unimolecular micelles

Novel Fréchet–PAMAM hybrid dendrimers linked by triazole units as unimolecular micelles with a hydrophobic core surrounded by a hydrophilic shell were prepared. The dendritic cores with 3 and 6 alkyne terminal groups were synthesized from 1,3,5-tribromomethyl-benzene (tBrMeB), in one case by direct coupling with 17α-ethynylestradiol (EE); in the second one the tBrMeB was reacted with bis(hydroxymethyl) phenol followed by chlorination of the hydroxyl groups and subsequent coupling to EE. With this strategy, the core can be grown by further substitutions of bis(hydroxymethyl) phenol over the halogenated terminals as Fréchet dendrimer. The hydrophilic shells used were PAMAM type dendrons of 0.5 and 1.5 generations with azide as focal point and tert-butyl ester as end groups. The unimolecular micelles were obtained by cycloaddition between an azide in the selected dendron and the alkyne terminal in the hydrophobic core to obtain a 1,4-disubstituted 1,2,3-triazole. Once the coupling was achieved, the tert-butyl ester groups were hydrolyzed in trifluoroacetic acid and the corresponding dendrimers with carboxylic acid as end groups were completely soluble in phosphate buffer solutions of pH 7.0, 7.4, and 8.0. All hybrid dendrimers were characterized by High Resolution Mass Spectrometry, 1H and 13C NMR, and FTIR.

Copper-catalyzed coupling of aryl iodides and tert-butyl β-keto esters: efficient access to α-aryl ketones and α-arylacetic acid tert-butyl esters

CuI/trans-4-hydroxy-l-proline catalyzed coupling of aryl iodides with tert-butyl β-keto esters proceeded smoothly at 40 °C in DMF, providing α-aryl ketones after acid-promoted deprotection and decarboxylation of tert-butyl ester group. While CuI/2-picolinic acid catalyzed coupling of aryl iodides with tert-butyl acetoacetate at 70 °C in dioxane delivered α-arylacetic acid tert-butyl esters upon spontaneous deacylation. A wide range of functional groups, such as acetyl, methoxy, nitrile, nitro, bromo, and chloro were compatible with the reaction conditions.

Self-Assembly of Amphiphilic Homopolymers Bearing Ferrocene and Carboxyl Functionalities: Effect of Polymer Concentration, β-Cyclodextrin, and Length of Alkyl Linker

Three new acrylamide monomers containing ferrocene and tert-butyl ester groups were first synthesized via multistep nucleophilic substitution reaction under mild conditions followed by reversible addition-fragmentation chain transfer (RAFT) homopolymerization to give well-defined homopolymers with narrow molecular weight distributions (M(w)/M(n) ≤ 1.36). The target amphiphilic homopolymers were obtained by the acidic hydrolysis of tert-butyoxycarbonyls to carboxyls in every repeating unit using CF3COOH. The self-assembly behaviors of these amphiphilic homopolymers bearing both ferrocene and carboxyl moieties in each repeating unit in aqueous media were investigated by transmission emission microscopy (TEM), dynamic light scattering (DLS), and atomic force microscopy (AFM). Large compound micelles with different morphologies were formed by these amphiphilic homopolymers, which consist of the corona formed by hydrophilic carboxyls and the core containing numerous reverse micelles with hydrophilic islands of carboxyls in continuous hydrophobic phase of ferrocene-based segments. The morphologies of the formed micelles could be tuned by the concentration of amphiphilic homopolymers, pH value of the solution, the length of -CH2 linker between ferrocene group and carboxyl, and the amount of β-cyclodextrin (β-CD).

Novel regular polyimide-graft -(polymethacrylic acid) brushes: Synthesis and possible applications as nanocontainers of cyanoporphyrazine agents for photodynamic therapy

An approach to the synthesis of new regular graft-copolymers polyimide (PI)-graft-polymethacrylic acid is elaborated, including (1) synthesis of multicenter PI macroinitiators, (2) controlled ATRP of tert-butylmethacrylate on the prepared macroinitiators, and (3) protonolysis of tert-butyl ester groups of side chains of the resulting PI-graft-poly(tert-butylmethacrylate). Experimental conditions for attaining complete conversions of the first and the third stages of the process are determined by means of 1H NMR and FTIR-spectroscopy. Polymer products of the first and the second stages of the process, as well as poly(tert-butylmethacrylate) side chains cleaved from the PI-graft-poly(tert-butylmethacrylate) copolymers by complete decomposition of the PI backbone under alkaline hydrolysis conditions, are characterized by GPC. The kinetics of poly(tert-butylmethacrylate) chain growth on a PI macroinitiator under ATRP conditions are studied. The results obtained provide evidence for the controlled character of the ATRP process and the regular structure of the synthesized graft-copolymers. It is shown that PI-g-PMAA PI brushes are significantly more efficient intracellular delivery agents for the potential photosensitizer [tetra(4-fluorophenyl)tetracyanoporhyrazine free base] than are the commonly used PEG-micelles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4267–4281

Synthesis of pH-responsive amphiphilic diblock copolymers containing polyisobutylene via oxyanion-initiated polymerization and their multiple self-assembly morphologies

Two pH-responsive amphiphilic diblock copolymers, namely polyisobutylene-block-poly[2-(N,N-dimethylamino) ethyl methacrylate] (PIB-b-PDMAEMA) and polyisobutylene-block-poly(metharylic acid) (PIB-b-PMAA), were synthesized via oxyanion-initiated polymerization, and their multiple self-assembly behaviors have been studied. An exo-olefin-terminated highly reactive polyisobutylene (HRPIB) was first changed to hydroxyl-terminated PIB (PIB-OH) via hydroboration-oxidation of C=C double bond in the chain end, and then reacted with KH to yield a potassium alcoholate of PIB (PIB-O−K+). PIB-O−K+ was immediately used as a macroinitiator to polymerize DMAEMA monomer, resulting in a cationic diblock copolymer PIB-b-PDMAEMA. With the similar synthesis procedure, the anionic diblock copolymer PIB-b-PMAA could be prepared via a combination of oxyanion-initiated polymerization of tert-butyl methacrylate (tBMA) and subsequent hydrolysis of tert-butyl ester groups in PtBMA block. The functional PIB and block copolymers have been fully characterized by 1H-NMR, FT-IR spectroscopy, and gel permeation chromatography (GPC). These samples allowed us to systematically investigate the effects of block composition on the pH responsivity and various self-assembled morphologies of the copolymers in THF/water mixed solvent. Transmission electron microscopy (TEM) images revealed that these diblock copolymers containing small amount of original PIB without exo-olefin-terminated group are able to self-assemble into micelles, vesicles with different particle sizes and cylindrical aggregates, depending on various factors including block copolymer composition, solvent polarity and pH value.

Functionalizing ps microspheres by supercritical deposition of P(S-b-tBA) for diverse interfacial properties exemplified with biocidal ability

Polystyrene (PS) microspheres were functionalized with poly(styrene-b-tert-butyl acrylate) (P(S-b-tBA)) by adsorption from supercritical mixture of CO2 and hexane. Supercritical deposition formed a shell-core structure that contained a shell of poly(tert-butyl acrylate) (PtBA) blocks and a core of the PS blocks entangling with the PS microspheres. The thickness of the PtBA layer and thereby the areal density of tert-butyl ester groups increased with the deposition pressure until plateau values attained at 20 MPa and higher. The tert-butyl ester groups were hydrolyzed to carboxyl groups for conjugation with tert-butylamine molecules via amide bonds that were further chlorinated into biocidal N-halamine moieties. The functionalization layer and its bonded N-halamine moieties were stable in flowing water and the chlorine could be regenerated upon eventual loss. This functionalization concept is applicable to polymers of any external and internal surfaces to achieve diverse surface properties by varying block copolymer and conjugated moieties.

Di-tert-butyl (2R,3R)-2-{[(2E)-3-(4-acet-yloxy-3-meth-oxy-phen-yl)prop-2-eno-yl]-oxy}-3-hy-droxy-butane-dioate.

In the title mol­ecule, C24H32O10, one tert-butyl ester group is folded towards the central benzene ring while the other is directed away. The acetyl group is almost perpendicular to the benzene ring to which it is connected [C—C—O—C torsion angle = 90.4 (12)°]. The conformation about the ethene bond [1.313 (7) Å] is E. The atoms of the benzene ring and its attached ester group and part of the hy­droxy tert-butyl ester side chain are disordered over two sets of sites in a 50:50 ratio. Linear supra­molecular chains along the a axis mediated by hy­droxy–carbonyl O—H⋯O hydrogen bonds feature in the crystal packing. The same H atom also partakes in an intra­molecular O—H⋯O inter­action.