Trends of microplastic abundance in personal care products in the United Arab Emirates over the period of 3 years (2018-2020)

Plastic microbeads in cosmetic products are considered one of the main contributors of primary microplastic pollution in aquatic environments. To assess the trends of microplastic usage in rinse-off cosmetic products over the last 3 years in the United Arab Emirates (UAE), 163 body scrub and face wash products were randomly selected and purchased from different UAE markets over a period of two (2019 and 2020) consecutive years as a continuation of our study of such products in 2018. Microbeads were extracted from the products and their composition was determined. The comparative analysis of the products revealed the presence of microplastic content in fewer products in 2019 and 2020 than to 2018. The results revealed that some of the products that contained microplastic in 2018 still have them in 2020. However, no new products were found on the market that contained microplastic. Overall, fewer products contained microbeads of any composition. Also, the consumer awareness, preferences, and behavior towards microplastic use in personal care products was assessed through a survey 2020 that complemented a survey carried out in 2018. An increasing awareness among the surveyed general public was noted regarding microplastic use in cosmetics and its adverse effects to the environment. The study indicates that an increasing global legislation is effective to curtail the use of microplastic containing microbeads in personal care products by replacing them with beads of alternative composition or avoiding the use of microbeads altogether. Nevertheless, products having microplastic content in the UAE were found to be imported or manufactured by companies based in countries where microplastic usage in personal care products has already been banned by law.

Microplastic Contamination of Chicken Meat and Fish through Plastic Cutting Boards

Microplastic contamination was found in fish and chicken bought on the market, in food stores and in chain supermarkets in the Middle East with the contamination ranging from 0.03 ± 0.04 to 1.19 ± 0.72 particles per gram of meat in chicken and from 0.014 ± 0.024 to 2.6 ± 2.8 particles per gram in fish. Only one fish was found to be free of microplastic. The source of the microplastic was established to be the polythene-based plastic cutting board the food was cut on. More microplastic contamination was found in food cut from the bone than in cut fillets when the fillets themselves were prepared on surfaces other than plastic. Washing the fish and chicken before food preparation decreased but did not completely remove the microplastic contamination. The fate of the microplastic in grilled fish was studied. The mechanical properties of typical plastic cutting boards commercially used in the markets were investigated in the form of tensile, hardness, and wear tests. Overall, the plastic cutting boards showed similar wear rates.

Plastic cutting boards as a source of microplastics in meat

Plastic cutting boards were found to be the source of polythene microplastic contamination in cut meat commercially available at butchers and a supermarket chain in the Middle East, making them also a direct source of microplastic in wastewater. The mean size of the microplastic in the raw meat was 1279.2 ± 835.0 µm, but decreased when the meat was cooked or fried. The microplastic melted during both cooking and frying processes and recrystallised partially upon cooling. Washing the meat for a short time (10 seconds) before preparing it reduced the microplastic contamination insignificantly, and only extensive washing of the meat over longer periods of time (3 min) helped decrease the microplastic count to 0.07 MP/g meat. The composition of the cutting boards was analysed by FT-IR spectroscopy, differential scanning calorimetry and subjected to wear, tensile and hardness tests. From a 3D photo of a spent cutting board, it was calculatedthat 875 g polythene was lost from the cutting board at the end of its lifetime.

Chemical Constituents and Uses of Calotropis Procera and Calotropis Gigantea – A Review (Part I – The Plants as Material and Energy Resources)

The traditional and current use of Calotropis procera and C. gigantea, two soft-wooded, xerophytic shrubs of the family Apocynaceae, are reviewed against the background of the plants' chemical constituents and their biological properties. The focus is on the usage of the plants for building materials, natural pesticides, animal feed and bioremediative purposes.

Analysis of microbeads in cosmetic products in the United Arab Emirates

The microparticle content of 37 common facial and body scrubs commercially available in the United Arab Emirates was analyzed. The chemical composition, ash content, physical characteristics, loading, particle size and shape of the microparticles were determined. Only 11 out of 37 products were found to have microplastic content. Many of the remaining products exhibited microparticles composed of microcrystalline cellulose and crushed walnut shells. Differential scanning calorimetry showed that microplastic products had softening points as low as 84 °C. Plastic microbeads of 2 products were found to fuse at 100 °C. The fusion altered the flotation characteristics of the microbeads of one product. Heat treatment of the product at 100 °C in the presence of silica gel led to entrainment of the silica and partial fragmentation of the beads upon cooling. This may be understood as one mechanism of fragmentation of a microplastic with a low softening point in the presence of hard soil particles under temperature cycling.

One pot Suzuki coupling – Wittig olefination reactions

Bromoarylcarbaldehydes and bromothienylcarbaldehydes undergo Suzuki cross coupling and Wittig reactions in a one pot procedure to give olefins with extended pi systems. Dihaloarenes can be transformed in a double Wittig – / double Suzuki cross coupling reaction to yield functionalised terphenyls.

Facile Access to Condensed Arenothiophenes – Preparation of Dihydrophenanthrothiophenes and Dihydrophenanthro[1]Benzothiophenes

4-Bromo-3-formyl-1,2-dihydronaphthalenes undergo Suzuki cross coupling and Wittig olefination reaction in a one pot procedure. The trienes obtained can be cyclised thermally under concomitant dehydrogenation to dihydrophenanthrothiophenes and dihydrophenanthro[1]benzothiophenes. An X-ray crystal structural analysis was carried out for ethyl (E)-3-[1-(1-benzothiophen-3-yl)-3,4-dihydro-2-naphthyl]propenoate.

A New Route to Non-Natural Aryl-Containing Amino Acids and Their Precursors from Thiophenes

Thiophenes may be converted to substituted arenes by oxidative cycloaddition to alkynes or by oxidative cycloaddition to alkenes with subsequent oxidative SO-extrusion. Cyano- and acetylamino-groups do not interfere in the reaction and are stable under the reaction conditions. This transformation can be used as a novel route to non-natural aryl-containing amino acids.

photochemistry of Substituted Dibenzothiophene S-Oxides and Oxygenated Bis-Dibenzothiophenes

Substituted dibenzothiophene and bis-dibenzothiophene S-oxides were prepared and submitted to photolysis. The rate of deoxygenation of the molecules under photoirradiation was found to be highly dependent on their substitution pattern.

A Series of 7-ω-carboxamidoalkyl-substituted estra-1,3,5(10),6-tetraenes

A number of 7-ω-carboxamidoalkyl-substituted estra-1,3,5(10),6-tetraenes as potential ligands for the estrogen receptor ERα have been prepared using either a conjugate addition of α,ω-iodoalkanenitriles or a Michael addition to steroidal ketone 3 as the key step.

Ring D 16,17-heteroannelated estranes

The synthesis of estranes bearing an additional heterocyclic ring attached to C-16 and C-17 is reviewed. Potential applications and biological activities of the compounds are described.

Solventless Wittig Olefination with Fluorinated Benzaldehydes

Fluorinated benzaldehydes undergo solventless Wittig olefination with stabilised phosphoranes. Even with less reactive, stabilised phosphoranes, such as acetylmethylidenetriphenylphosphorane, the reactions have been found to be exothermic.

One pot Sonogashira-coupling/Wittig olefination procedures

Bromoarylcarbaldehydes, bromoheteroarylcarbaldehydes, and bromoalkenals can be subjected to a one pot Sonogashira coupling–Wittig olefination reaction to give easy access to molecules with extended pi-systems.

Thiophene S-oxides

Methods for the preparation of thiophene S-oxides, their roles in thiophene metabolism, and the structures and chemical reactivity of these compounds, are discussed.

The conformation of some estrane acetals

The X-ray crystal structures of a number of 6-ketoestra-1,3,5(10)-trien-17-ones and 6-ketoestra-1,3,5(10)-triene-17-one 17-O,O-acetals have been determined and the effect of the acetal group on the conformation of rings B and D are discussed.

N-Benzylcinnamamide

In the title compound, C16H15NO, there is a weak intramolecular C—H...O contact which leads to a planar acrylamide moiety. The phenyl ring forms an angle of 8.30 (2)° with the mean plane of the acrylamide moiety. The benzyl group is tilted against the cinnamamide unit, with the ring forming an angle of 77.11 (2)° with the cinnamamide unit mean plane. In the crystal, molecules are linkedviaN—H...O and C—H...O hydrogen bonds and C—H...π interactions, forming chains propagating along [001]. The chains are linkedviafurther C—H...π interactions, forming layers parallel to theacplane.

Crystal structure of (1Z,2E)-cinnamaldehyde oxime

The title compound, C9H9NO, crystallized with two independent molecules (AandB) in the asymmetric unit. The conformation of the two molecules differs slightly with the phenyl ring in moleculeA, forming a dihedral angle of 15.38 (12)° with the oxime group (O—N=C), compared to the corresponding angle of 26.29 (11)° in moleculeB. In the crystal, theAandBmolecules are linked head-to-head by O—H...N hydrogen bonds, forming –A–B–A–B– zigzag chains along [010]. Within the chains and between neighbouring chains there are C—H...π interactions present, forming a three-dimensional structure.

Molecular conformational analysis, vibrational spectra, NBO, NLO, HOMO-LUMO and molecular docking studies of ethyl 3-(E)-(anthracen-9-yl)prop-2-enoate based on density functional theory calculations

FT-IR and FT-Raman spectra of ethyl 3-(E)-(anthracen-9-yl)prop-2-enoate were recorded and analyzed. The conformational behavior of the molecule was also investigated. The vibrational wavenumbers were calculated using DFT quantum chemical calculations. The data obtained from the wavenumber calculations were used to assign vibrational bands obtained experimentally. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis were used to determine the charge transfer within the molecule and quantum chemical parameters related to the title compound. From the MEP analysis, it is clear that the negative electrostatic potential regions are mainly localized over the carbonyl groups and anthracene ring and are possible sites for electrophilic attack and the positive regions are localized at all the hydrogen atoms as possible sites for nucleophilic attack. NLO and NMR studies are also reported. Molecular docking studies suggest that the title compound might exhibit inhibitory activity against IDE and may act as an insulysin inhibitor. Conformational analysis is also reported.

Molecular conformational analysis, vibrational spectra, NBO, NLO analysis and molecular docking study of bis[(E)-anthranyl-9-acrylic]anhydride based on density functional theory calculations

FT-IR and FT-Raman spectra of bis[(E)-anthranyl-9-acrylic]anhydride were recorded and analyzed. The conformational behavior is also investigated. The vibrational wave numbers were calculated using density functional theory (DFT) quantum chemical calculations. The data obtained from wave number calculations are used to assign vibrational bands obtained in Infrared and Raman spectra. Potential energy distribution was done using GAR2PED program. The geometrical parameters are compared with related structures. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using Natural Bonding Orbital (NBO) analysis. The Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) analysis are used to determine the charge transfer within the molecule. Molecular Electrostatic Potential (MEP) was performed by the DFT method. The calculated first hyperpolarizability of the title compound is comparable with the reported values of similar derivatives and is 4.23 times that of the standard nonlinear optical (NLO) material urea and the title compound and its derivatives are an attractive object for future studies of nonlinear optical properties. To evaluate the in silico antitumor activity of the title compound molecular docking studies were carried out against protein Bcl-xL. The (1)H-NMR spectrum is also reported.

Crystal structure of 3-(2,5-dimethoxyphenyl)propionic acid

In the crystal of the title compound, C₁₁H₁₄O₄, the aromatic ring is almost coplanar with the 2-position meth­oxy group with which it subtends a dihedral of 0.54 (2)°, while the 5-position meth­oxy group makes a corresponding dihedral angle of just 5.30 (2)°. The angle between the mean planes of the aromatic ring and the propionic acid group is 78.56 (2)°. The fully extended propionic side chain is in a trans configuration with a C—C—C—C torsion angle of −172.25 (7)°. In the crystal, hydrogen bonding is limited to dimer formation via R₂²(8) rings. The hydrogen-bonded dimers are stacked along the b axis. The average planes of the two benzene rings in a dimer are parallel to each other, but at an offset of 4.31 (2) Å. Within neighbouring dimers along the [101] direction, the average mol­ecular benzene planes are almost perpendicular to each other, with a dihedral angle of 85.33 (2)°.

Crystal structure of cholest-5-en-3β-yl 3-(2,4-dimethoxy-3-methylphenyl)prop-2-enoate

In the title compound, C₃₉H₅₈O₄, the steroid rings A and C adopt a chair conformation, while ring B adopts a half-chair conformation, and ring D has an envelope conformation, with the methyl-substituted C atom as the flap. In the crystal, mol­ecules pack within layers parallel to (100), with their long axis parallel to the [101] direction. Adjacent layers are linked via C—H⋯O hydrogen bonds and C—H⋯π inter­actions, forming a three-dimensional framework.

Molecular conformational analysis, vibrational spectra, NBO analysis and first hyperpolarizability of (2E)-3-(3-chlorophenyl)prop-2-enoic anhydride based on density functional theory calculations

The conformational behavior and structural stability of (2E)-3-(3-chlorophenyl)prop-2-enoic anhydride were investigated by using density functional theory. The optimized molecular structure, vibrational wavenumbers, corresponding vibrational assignments of (2E)-3-(3-chlorophenyl)prop-2-enoic anhydride have been investigated experimentally and theoretically. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated first hyperpolarizability of the title compound is 15.8×10(-30)esu, and is 121.54 times that of the standard NLO material urea and the title compound is an attractive object for future studies of nonlinear optical properties. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported.

Vibrational spectra, molecular structure, NBO, HOMO-LUMO and first order hyperpoalarizability analysis of 1,4-bis(4-formylphenyl)anthraquinone by density functional theory

Anthraquinone derivatives are most important class of a system that absorb in the visible region. Infrared and Raman spectroscopic analyses were carried out on 1,4-bis(4-formylphenyl)anthraquinone. The interpretation of the spectra was aided by DFT calculations of the molecule. The vibrational wavenumbers were examined theoretically using the Gaussian09 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. A computation of the first hyperpolarizability of the compound indicates that this class of substituted anthraquinones may be a good candidate as a NLO material. Optimized geometrical parameters of the compound are in agreement with similar reported structures. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis.

Crystal structure of 2-pentyl-oxybenzamide

In the title mol-ecule, C12H17NO2, the amide NH2 group is oriented toward the pent-yloxy substituent and an intra-molecular N-H⋯O hydrogen bond is formed with the pent-yloxy O atom. The benzene ring forms dihedral angles of 2.93 (2) and 5.60 (2)° with the amide group and the pent-yloxy group mean planes, respectively. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with their mol-ecular planes parallel, but at an offset of 0.45 (1) Å to each other. These dimers are ordered into two types of symmetry-related columns extended along the a axis, with the mean plane of one set of dimers in a column approximately parallel to (121) and the other in a column approximately parallel to (1-21). The two planes form a dihedral angle of 85.31 (2)°, and are linked via C-H⋯O hydrogen bonds and C-H⋯π inter-actions, forming a three-dimensional framework structure.

Molecular conformational analysis, vibrational spectra, NBO analysis and first hyperpolarizability of (2E)-3-phenylprop-2-enoic anhydride based on density functional theory calculations

The conformational behavior and structural stability of (2E)-3-phenylprop-2-enoic anhydride were investigated by using density functional theory. Seventeen possible stable conformations of the title compound were determined and verified with their calculated vibrational frequencies being all positive. The optimized molecular structure, vibrational wavenumbers, corresponding vibrational assignments of (2E)-3-phenylprop-2-enoic anhydride have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes vibrations was done using GAR2PED program. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated first hyperpolarizability of the title compound is 12×10(-30) esu and is 92.31 times that of the standard NLO material urea and the title compound is an attractive object for future studies of nonlinear optical properties. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported.

Synthesis and Radiosynthesis of 17α-[p-(Iodophenylethynyl)]estra-3,17β-diols

Estrones have been subjected to an addition reaction with [(4-ethynylphenyl)azo]pyrrolidine to provide 17 α-{4-[(pyrrolidin-1-yl)-azo]phenylethynyl}estra-3,17 β -diols. A subsequent iodination with iodotrimethylsilane, produced in situ from chlorotrimethylsilane and NaI, leads to 17α-(piodophenylethynyl) estra-3,17 β -diols. This reaction can also be carried out with Na125 I to give radiolabelled estra-3,17 β -diols, which are potentially useful radiodiagnostic agents for the detection of estrogen positive breast cancer. The stability of the radiolabelled compounds is exemplified in a stability study of 3-O-methyl 17 α-(p-[125 I]iodophenylethynyl)estra-1,3,5(10),6-tetraene-17 β -ol in acetonitrile.

Combined Suzuki Coupling – Wittig Olefination Reaction in Aqueous Medium

Bromoarene carbaldehydes and bromoheteroarene carbaldehydes underwent a one-pot Suzuki cross coupling and Wittig olefination in aqueous medium to give compounds with extended π-systems.

Fluoren-9-one oxime

In the title mol­ecule, C₁₃H₉NO, the fluorene system and the oxime group non-H atoms are essentially coplanar, with a maximum deviation from the fluorene mean plane of 0.079 (2) Å for the oxime O atom. A short intra­molecular C—H⋯O generates an S(6) ring. In the crystal, mol­ecules related by a twofold screw axis are connected by O—H⋯N hydrogen bonds, forming [100] chains Within these chains, mol­ecules related by a unit translation along [100] show π–π stacking inter­actions between their fluorene ring systems with an inter­planar distance of 3.347 (2) Å. The dihedral angle between the fluorene units of adjacent mol­ecules along the helix is 88.40 (2)°. There is a short C—H⋯π contact between the fluorene groups belonging to neighbouring chains.

Two Ways of Preparing Benzonitriles Using BrCCl3–PPh3 as the Reagent

Benzamides were converted into benzonitriles with BrCCl3–PPh3–Et3N in CH2Cl2 in an Appel-type reaction. Benzaldoximes could be transformed to benzonitriles under identical conditions. It was found that the reaction system BrCCl3–(2 equiv.)PPh3 was also suitable for these transformations with PPh3 replacing Et3N.

Spectroscopic (FT-IR, FT-Raman), first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2,4-bis(2-methoxyphenyl)-1-phenylanthracene-9,10-dione by ab initio HF and density functional methods

Anthraquinone derivatives are most important class of a system that absorb in the visible region. In this work, the vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy for 2,4-bis(2-methoxyphenyl)-1-phenylanthracene-9,10-dione. Theoretical calculations were performed by ab initio HF and DFT methods using 6-31G(*) basis set. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters (DFT) are in agreement with that of similar derivatives. The calculated first hyperpolarizability of the title compound is 4.69×10(-30) esu, which is 36.08 times that of urea and the title compound and the series of compounds it represents are attractive candidates for further studies in non linear optical applications.

2,5-Di-meth-oxy-benzo-nitrile

In the title mol­ecule, C₉H₉NO₂, the non-H atoms are essentially coplanar with a maximum deviation of 0.027 (2) Å for the C atom of one of the methyl groups. In the crystal, the mol­ecules are arranged into centrosymmetric pairs via pairs of C—H⋯O and C—H⋯N inter­actions whereas π–π stacking inter­actions between the benzene rings [centroid–centroid distance 3.91001 (15) Å] organize them into polymeric strands propagating along the a-axis direction. There is a step of 0.644 (2) Å between the two planar parts of the centrosymmetric pair. In neighboring strands related by the n-glide operation, the aromatic rings are tilted by 29.08 (2)°.

Intermolecular interactions between cucurbit[7]uril and pilocarpine

The interactions between cucurbit[7]uril (CB7) macrocycles and pilocarpine (PIL) were investigated in aqueous solution by using (1)H NMR and circular dichroism (CD) spectroscopic techniques. The characterizations of the freeze-drying solid complex were conducted by electrospray ionization mass spectroscopy (ESI-MS), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetry, and differential scanning calorimetry (DSC) techniques. The DSC and thermogravimetry confirmed the production of a thermally stable solid complex. The NMR, CD and ESI-MS measurements confirmed asymmetric induction during the complexation reaction, in which the γ-lactone ring of PIL (not the imidazole nucleus) has been fully encapsulated within the cavity of CB7. The stability of the drug has significantly enhanced as evidenced by the high-performance liquid chromatographic (HPLC) method. The results are discussed in the context of utilizing non-conventional supramolecular host-guest approaches to enhance the chemical stability in aqueous media of hydrophilic PIL drugs as model compounds. The non-classical stereospecific interactions between CB7 and PIL drugs are also highlighted.

(E)-Methyl 3-(10-bromo-anthracen-9-yl)acrylate

In the title mol-ecule, C18H13BrO2, the anthracene unit forms an angle of 46.91 (2)° with the mean plane of the methyl acrylate moiety. In the crystal, the mol-ecules arrange themselves into strands parallel to [010] and, due to the crystal symmetry, there are eight strands crossing the unit cell. In each strand, mol-ecules form short C-H⋯O and C-H⋯π contacts and have their anthracene groups parallel to each other. Neighboring strands, related by a c-glide operation, are connected via C-H⋯O inter-actions and form a layer parallel to (100). The arrangement of the acrylate and anthracene groups in the crystal do not allow for [2 + 2] or [4 + 4] cyclo-addition.

Steroid receptor ligands for breast cancer targeting: an insight into their potential role as PET imaging agents

The design and development of radiolabelled steroid derivatives has been an important area of research due to their wellknown value in breast cancer targeting. The estrogen receptor (ER) and progesterone receptor (PR) are important biomarkers in the diagnosis, prognosis and follow-up of the therapeutic response of breast tumours. Thus, several radioligands based on estrogens and progestins have been proposed for targeted functional ER imaging. The aim of this review is to survey and analyze the developments in this field, which have led to the design of a number of PET steroid-based imaging agents, a few of which seem to be promising as radiopharmaceuticals for detection of ER-positive breast tumours.

Progesterone receptor targeting with radiolabelled steroids: an approach in predicting breast cancer response to therapy

Steroid receptors have demonstrated to be potentially useful biological targets for the diagnosis and therapy follow-up of hormonally responsive cancers. The over-expression of these proteins in human cancer cells as well as their binding characteristics provides a favourable mechanism for the localization of malignant tumours. The need for newer and more selective probes to non-invasively assess steroid receptor expression in hormone-responsive tumours has encouraged the synthesis and the biological evaluation of several steroidal derivatives labelled with positron and gamma emitters. The physiological effects of the steroid hormone progesterone are mediated by the progesterone receptor (PR). Since PR expression is stimulated by the oestrogen receptor (ER), PR status has been considered as a biomarker of ER activity and its value for predicting and monitoring therapeutic efficacy of hormonal therapy has been studied. Imaging of PR-expressing breast cancer patients under hormonal therapy may be advantageous, since the response to therapy can be more accurately predicted after quantification of both ER and PR status. Thus, ligands for PR targeting, although much less explored than ER ligands, have gained some importance lately as potential PET and SPECT tumour imaging agents. In this review, we present a brief survey of explored approaches for progesterone targeting using radiolabelled progestins as potential clinical probes to predict responsiveness to breast cancer therapy. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Ethyl (E)-3-(anthracen-9-yl)prop-2-enoate

In the asymmetric unit of the title compound, C₁₉H₁₆O₂, there are two symmetry-independent mol­ecules (A and B) that differ in the conformation of the ester eth­oxy group. In the crystal, the mol­ecules form inversion dimers via pairs of C—H⋯O inter­actions. Within the dimers, the anthracenyl units have inter­planar distances of 0.528 (2) and 0.479 (2) Å for dimers of mol­ecules A and B, respectively. Another short C—H⋯O contact between symmetry-independent dimers links them into columns parallel to [10-1]. These columns are arranged into (111) layers and there are π–π stacking inter­actions [centroid–centroid distances = 3.6446 (15) and 3.6531 (15) Å] between the anthracenyl units from the neighbouring columns. In addition, there are C—H⋯π inter­actions between the anthracenyl unit of dimers A and dimers B within the same column.

2-(Prop-2-enyloxy)benzamide

In the title mol­ecule, C₁₀H₁₁NO₂, the benzene ring forms dihedral angles of 33.15 (2) and 6.20 (2)° with the mean planes of the amide and propen­oxy groups, respectively. The amide –NH₂ group is oriented toward the propen­oxy substituent and forms a weak intra­molecular N—H⋯O hydrogen bond to the propen­oxy O atom. The conformation of the propen­oxy group at the Csp²—Csp³ and Csp³—O bonds is synperiplanar and anti­periplanar, respectively. In the crystal, N—H⋯O hydrogen bonds involving the amide groups generate C(4) and R²₃(7) motifs that organize the mol­ecules into tapes along the a-axis direction. There are C—H⋯π inter­actions between the propen­oxy –CH₂ group and the aromatic system of neighboring mol­ecules within the tape. The mean planes of the aromatic ring and the propen­oxy group belonging to mol­ecules located on opposite sites of the tape form an angle of 83.16 (2)°.

Novel 7α-alkoxy-17α-(4'-halophenylethynyl)estradiols as potential SPECT/PET imaging agents for estrogen receptor expressing tumours: synthesis and binding affinity evaluation

In order to develop potential radiolabelled probes for imaging estrogen receptor (ER) positive tumours, we have synthesized and characterized a series of novel 7α-alkoxy-17α-(4'-iodophenylethynyl)estra-1,3,5(10)-triene-3,17β-diols and 7α-alkoxy-17α-(4'-fluorophenylethynyl)estra-1,3,5(10)-triene-3,17β-diols. The fluoro-substituted compounds showed a higher ER binding affinity than the corresponding iodo-derivatives, where 7α-methoxy- and 17α-(4'-fluorophenylethynyl)estra-1,3,5(10)-triene-3,17β-diol showed the highest ER binding affinities (RBA=80.9% and 78.9%, respectively), among the halophenylethynyl compounds studied and should be further explored as potential PET biomarkers for imaging of ER expressing tumours.