Methyl 3‐(4‐methoxyphenyl)prop‐2‐enoate

The title mol­ecule, C₁₁H₁₂O₃, is almost planar, with an average deviation of the C and O atoms from the least‐squares plane of 0.146 (4) Å. The geometry about the C=C bond is trans. The phenyl ring and –COOCH₃ group are twisted with respect to the double bond by 9.3 (3) and 5.6 (5)°, respectively. The endocyclic angle at the junction of the propenoate group and the phenyl ring is decreased from 120° by 2.6 (2)°, whereas two neighbouring angles around the ring are increased by 2.3 (2) and 0.9 (2)°. This is probably associated with the charge‐transfer interaction of the phenyl ring and –COOCH₃ group through the C=C double bond. The mol­ecules are joined together through C—H?O hydrogen bonds between the methoxy and ester groups to form characteristic zigzag chains extended along the c axis.     

3,3,4,4,5,5‐Hexafluoro‐1‐(2‐methoxyphenyl)‐2‐[5‐(4‐methoxyphenyl)‐2‐methyl‐3‐thienyl]cyclopent‐1‐ene: a photochromic compound

The photochromic title compound, C₂₄H₁₈F₆O₂S, has thienyl and aryl substituents on the C=C double bond of the shallow half‐chair‐shaped cyclopentene ring. The planes of the two substituent rings are inclined to that of the cyclopentene ring, with dihedral angles between the mean plane of the cyclopentene ring and those of the phenylene and thienyl rings of 51.2 (1) and 51.3 (1)°, respectively. The molecule adopts an antiparallel conformation, with a distance between the two photoreactive C atoms of 3.717 (2) Å.     

2‐(3‐tert‐Butyldimethylsiloxy‐4‐methoxyphenyl)‐6‐methoxy‐3‐(3,4,5‐trimethoxybenzoyl)indole

In the crystal structure of the title compound, C₃₂H₃₉NO₇Si, all geometric parameters fall within experimental error of expected values. The analysis of molecular‐packing plots reveals an infinite two‐dimensional linear array running parallel to the b axis, formed by one N—H?O intermolecular hydrogen‐bonding interaction. Several potential C—H?O interactions are also present.     

Conformational Polymorphism in N‐(4′‐methoxyphenyl)‐ 3‐bromothiobenzamide

Three conformational polymorphs of N‐(4′‐methoxyphenyl)‐3‐bromothiobenzamide, yellow α, orange β, and yellow γ, have been identified by single‐crystal X‐ray diffraction. The properties and structure of the polymorphs were examined with FT Raman, FTIR (ATR), and UV/Vis spectroscopy, as well as differential scanning calorimetry. Computational data on rotational barriers in the isolated gas‐phase molecule indicate that the molecular conformation found in the α form is energetically preferred, but only by around 2 kJ mol^?1 over the γ conformation. The planar molecular structure found in the β form is destabilized by 10–14 kJ mol^?1, depending on the calculation method. However, experimental evidence suggests that the β polymorph is the most stable crystalline phase at room temperature. This is attributed to the relative planarity of this structure, which allows more and stronger intermolecular interactions, that is, more energetically effective packing. Calculated electronic‐absorption maxima were in agreement with experimental spectra.     

A Convenient Synthesis of 6,8-Dimethoxy-3-[（2-（4-methoxyphenyl）ethyl）isocoumarin

6,8-Dimethoxy-3-[2-（4-methoxyphenyl）ethyl]isocoumarin was synthesized by condensation of 5,7-dimethoxyhompophthalic acid with 3-（4-methoxyphenyl）propanoyl chloride. The structure of the synthesized compound was confirmed by its mass spectrometric studies. The synthesized compound serves as a model for synthesis of DL-agrimonolide.     

3‐[5‐(4‐Chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid and the corresponding methyl ester

The synthesis of 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid, C₁₉H₁₇ClN₂O₃, (I), and its corresponding methyl ester, methyl 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionate, C₂₀H₁₉ClN₂O₃, (II), is regiospecific. However, correct identification of the regioisomer formed by spectroscopic techniques is not trivial and single‐crystal X‐ray analysis provided the only means of unambiguous structure determination. Compound (I) crystallizes with Z′ = 2. The propionic acid groups of the two crystallographically unique molecules form a hydrogen‐bonded dimer, as is typical of carboxylic acid groups in the solid state. Conformational differences between the methoxybenzene and pyrazole rings give rise to two unique molecules. The structure of (II) features just one molecule in the asymmetric unit and the crystal packing makes greater use than (I) of weak C—H...A interactions, despite the lack of any functional groups for classical hydrogen bonding.