2-{3,4-Dibut­oxy-5-[5-(3-methyl­phen­yl)-1,3,4-oxadiazol-2-yl]thio­phen-2-yl}-5-(3-methyl­phen­yl)-1,3,4-oxadiazole

In the title compound, C30H32N4O4S, the dihedral angles between the central thio­phene ring and the pendant oxadiazole rings are 10.1 (2) and 6.8 (3)°. The dihedral angles between each oxadiazole ring and its adjacent benzene ring are 6.8 (2) and 5.3 (3)°

Resolving the energy and temperature dependence of C₆ H₆ ∗ collisional relaxation via time-dependent bath temperature measurements

The relaxation of highly vibrationally excited benzene, generated by 193 nm laser excitation, was studied using the transient rotational-translational temperature rise of the N2 bath, which was measured by proxy using two-line laser induced fluorescence of seeded NO. The resulting experimentally measured time-dependent N2 temperature rises were modeled with MultiWell based simulations of Collisional Energy Transfer (CET) from benzene vibration to N2 rotation-translation. We find that the average energy transferred in benzene deactivating collisions depends linearly on the internal energy of the excited benzene molecules and depends approximately linearly on the N2 bath temperature between 300 K and 600 K. The results are consistent with experimental studies and classical trajectory calculations of CET in similar systems

Control of cationic amino acid transport and retroviral receptor functions in a membrane protein family

A partial cDNA sequence indicated that the T lymphocyte early-activation gene (Tea) encodes a protein related to the dual-function ecotropic retrovirus receptor/cationic amino acid transporter (ecoR/CAT1), and RNA blots suggested highest Tea expression in T lymphocytes and liver (MacLeod, C.L., Finley, K., Kakuda, D. Kozad, C.A., and Wilkinson, M.F. (1990) Mol. Cell. Biol. 7, 3663-3674). The sequence of full-length Tea cDNA from liver (3683 bases) predicts a 657-amino-acid protein (CAT2 alpha) with 12-14 transmembrane domains. A long (515 base) region with six initiation codons and termination codons precedes the translation start codon. The liver Tea cDNA is identical to Tea cDNA from T lymphocytes (encoding CAT2 beta) with the exception of an apparent alternatively spliced sequence encoding a hydrophilic loop of 43 amino acids. The liver-specific sequence contains unique consensus sites for phosphorylation by cyclic AMP-dependent protein kinase and by protein kinase C. Injection of Xenopus oocytes with CAT2 alpha or CAT2 beta messenger RNA resulted in expression of Na(+)-independent cationic amino acid transport that was detected by current measurements under voltage-clamp. Although the amino acid sequences of the isoforms differ in only 21 of 43 residues with the majority of substitutions being conservative, the apparent affinity of CAT2 beta for arginine uptake was 70-fold higher than the CAT2 alpha isoform (Km 38 microM versus 2.7 mM). Neither isoform functioned as a receptor for ecotropic or amphotropic murine retroviruses. However, CAT1-CAT2 chimeric proteins that contain the first three putative extracellular loops of ecoR/CAT1 functioned as ecotropic receptors despite a diminished capacity to bind the viral envelope glycoprotein. The chimeric proteins also functioned as basic amino acid transporters with substrate affinities corresponding to the CAT2 isoform constituting the carboxyl-terminal portion. These results demonstrate that domains of these transporters can function in chimeric combinations to control viral receptor and transport functions

2-[2-(4-Nitro­phenyl)hy­dra­zin­yl­idene]malononitrile

The title compound, C10H8N8, is close to planar (r.m.s. deviation from the mean plane = 0.118 Å). In the crystal, inversion dimers linked by pairs of N—H⋯N hydrogen bonds generate R 2 2(12) loops

Methyl 4-(3-chloro­prop­oxy)-3-methoxy­benzoate

In the title compound, C12H15ClO4, the molecules are linked by C—H⋯O interactions

Methyl 4-(3-chloro­prop­oxy)-5-meth­oxy-2-nitro­benzoate

The asymmetric unit of the title compound, C12H14ClNO6, contains two crystallographically independent mol­ecules, in which the benzene rings are oriented at a dihedral angle of 9.12 (3)°. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network

Methyl 4-but­oxy-3-methoxy­benzoate

The title compound, C13H18O4, is an inter­mediate product in the synthesis of quinazoline derivatives. Crystal structure analysis shows that the benzene–butoxy Car—O—C—C torsion angle is 175.3 (2)° and that the benzene–methoxycarbonyl Car—C—O—C torsion angle is 175.2 (2)°. Torsion angles close to 180° indicate that the molecule is almost planar

N-(4-Isopropoxyphen­yl)acetamide

In the mol­ecule of the title compound, C11H15NO2, the planar acetamide unit [maximum deviation of 0.0014 (6) Å] is oriented at a dihedral angle of 19.68 (4)° with respect to the aromatic ring. An intra­molecular C—H⋯O inter­action results in the formation of a six-membered ring. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains along the a axi

Methyl 2-amino-4-(3-chloro­prop­oxy)-5-methoxy­benzoate

The asymmetric unit of the title compound, C12H16ClNO4, contains two crystallographically independent mol­ecules. The benzene rings of the two independent mol­ecules are oriented at a dihedral angle of 88.50 (3)°. Intra­molecular N—H⋯O hydrogen bonds involving the methoxybenzoate carbonyl group in each molecule result in the formation of two planar, six-membered rings, oriented at dihedral angles of 1.39 (3) and 0.68 (3)° with respect to the adjacent benzene rings. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains along the a axis

Bis(3-nitro­phen­yl) sulfone

The asymmetric unit of the title compound, C12H8N2O6S, an important diphenyl sulfone derivative, contains one half-mol­ecule; a mirror plane passes through the SO2 group. The dihedral angle between the two symmetry-related benzene rings is 40.10 (13)°. An intra­molecular C—H⋯O hydrogen bond results in the formation of a five-membered ring, which adopts an envelope conformation