Bis(dimethylamine-κN)bis[4-(1,2,4-triazol-1-yl)benzoato-κO]copper(II)

In the title compound, [Cu(C9H6N3O2)2(C2H7N)2], the Cu2+ cation is situated on an inversion center and is coordinated by the N atoms of two dimethylamine ligands and the carboxylate O atoms of two 4-(1,2,4-triazol-1-yl)benzoate anions, leading to a slightly distorted square-planar N2O2 coordination environment. In the crystal, intermolecular N—H...N hydrogen bonds between the amine function and the central N atom of the triazole ring lead to the formation of ribbons parallel to [1\overline{1}1]. Weak intermolecular C—H...O hydrogen-bonding interactions are also observed that consolidate the crystal packing.

Stereodivergent Synthesis of Camphor-Derived Diamines and Their Application as Thiourea Organocatalysts

A series of 18 regio- and stereo-chemically diverse chiral non-racemic 1,2-, 1,3-, and 1,4-diamines have been synthesized from commercial (1S)-(+)-ketopinic acid and (1S)-(+)-10-camphorsulfonic acid. The structures of the diamines are all based on the d-(+)-camphor scaffold and feature isomeric diversity in terms of regioisomeric attachment of the primary and the tertiary amine function and the exo/endo-isomerism. Diamines were transformed into the corresponding noncovalent bifunctional thiourea organocatalysts, which have been evaluated for catalytic activity in the conjugative addition of 1,3-dicarbonyl nucleophiles (dimethyl malonate, acetylacetone, and dibenzoylmethane) to trans-β-nitrostyrene. The highest enantioselectivity was achieved in the reaction with acetylacetone as nucleophile using endo-1,3-diamine derived catalyst 52 (91.5:8.5 er). All new organocatalysts 48–63 have been fully characterized. The structures and the absolute configurations of eight intermediates and thiourea derivative 52 were also determined by X-ray diffraction.

Early Postnatal Manganese Exposure Reduces Rat Cortical and Striatal Biogenic Amine Activity in Adulthood

Growing evidence from studies with children and animal models suggests that elevated levels of manganese during early development lead to lasting cognitive and fine motor deficits. This study was performed to assess presynaptic biogenic amine function in forebrain of adult Long-Evans rats exposed orally to 0, 25, or 50 mg Mn/kg/day over postnatal day 1–21 or continuously from birth to the end of the study (approximately postnatal day 500). Intracerebral microdialysis in awake rats quantified evoked outflow of biogenic amines in the right medial prefrontal cortex and left striatum. Results indicated that brain manganese levels in the early life exposed groups (postnatal day 24) largely returned to control levels by postnatal day 66, whereas levels in the lifelong exposed groups remained elevated 10%–20% compared with controls at the same ages. Manganese exposure restricted to the early postnatal period caused lasting reductions in cortical potassium-stimulated extracellular norepinephrine, dopamine, and serotonin, and reductions in striatal extracellular dopamine. Lifelong manganese exposure produced similar effects with the addition of significant decreases in cortical dopamine that were not evident in the early postnatal exposed groups. These results indicate that early postnatal manganese exposure produces persistent deficits in cortical and striatal biogenic amine function. Given that these same animals exhibited lasting impairments in attention and fine motor function, these findings suggest that reductions in catecholaminergic activity are a primary factor underlying the behavioral effects caused by manganese, and indicate that children exposed to elevated levels of manganese during early development are at the greatest risk for neuronal deficiencies that persist into adulthood.

Acyl Transfer Strategies as Transient Activations for Enantioselective Synthesis

In order to circumvent reactivity or selectivity issues associated with the addition of enolates to electrophiles, chemists have devised innovative methods involving transient activating groups. One of these powerful methods consists of the use of activated ketones, such as α-nitroketones, β-dicarbonyl compounds or β-ketosulfones, with electrophiles possessing a latent hydroxy or amine function. In the presence of a suitable catalyst, an enantioselective addition to the electrophile is facilitated triggering a subsequent Claisen-type fragmentation resulting in an acyl transfer. This subsequent step unveils the desired mono-activated function while directly transferring the ketone, forming in situ on the other side an ester or an amide.1 Introduction2 Intramolecular Acyl Transfer with Acyclic Substrates2.1 Bifunctional Catalysis2.2 Aminocatalysis3 Intermolecular Acyl Transfer with Acyclic Substrates4 Medium-Sized-Ring Formation with Cyclic Substrates5 Conclusion

Controlled usage of H/D exchange to circumvent concomitant polymorphs of ROY

The hypothesis that H/D exchange affects the structural formation of organic compounds in the solid state is supported by a deeper understanding of the altering polymorphism of ROY (a substance striking for its high number of polymorphic forms) through deuteration. Therefore, ROY was deuterated at its amine function, which leads to a seemingly small yet effective modification of the hydrogen-bond strength. In contrast to the crystallization of the non-deuterated ROY in methanol or ethanol, which leads to the simultaneous formation of two forms (OP and Y polymorphs), so-called concomitant polymorphs, the crystallization of d 1-ROY leads to the selective formation of the Y polymorph exclusively. The preferred aggregation behavior of the Y form of d 1-ROY is assigned to the weakening of an intramolecular hydrogen bond and a consequently strengthened intermolecular hydrogen bond after deuteration.

Crystal structure of 2-(1H-imidazol-3-ium-4-yl)ethanaminium dichloride, a re-determination

The crystal structure of the title molecular salt, C5H11N3+·2Cl−, was redetermined. In comparison with the previous study [Bonnetet al.(1975).Bull. Soc. Fr. Mineral. Crist.98, 208–213.], the positions of some H atoms were corrected, allowing a more accurate description of the hydrogen-bonding scheme. In addition, the absolute structure was also determined. The maximum differences in terms of bond lengths and angles between the two determinations are 0.022 Å and 1.43°, respectively. The organic cation display aanticonformation of the protonated amine function and the imidazolium ring. The dihedral angle between the imidazolium plane and the plane through the C—C—N side chain is 29.58 (3)°. In the crystal, the organic cations and Cl−anions are stacked alternatively into layers parallel to (100). N—H...Cl hydrogen bonds between all H atoms of the ammonium group and both N—H groups of the imidazolium ring and the Cl−acceptor anions lead to the linkage of organic and inorganic layers into a three-dimensional network.

[2-(3,4-Dimethoxyphenyl)ethyl](3-{N-[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl}propyl)azanium chloride dihydrate

The asymmetric unit of the title hydrated salt, C24H35N2O5+·Cl−·2H2O, contains one organic cation that has its protonation site at the amine function, one chloride anion and two lattice water molecules. In the crystal, one pair of lattice water molecules and two chloride anions form a four-membered centrosymmetric hydrogen-bond cycle. In addition, O—H...O, N—H...O and N—H...Cl hydrogen bonds involving the N—H groups, the water molecules and the C=O group are observed. As a result, a hydrogen-bonded layer parallel to (100) is formed. The thickness of such a layer corresponds to the length of theaaxis [21.977 (3) Å].

N1-(Thiophen-2-ylmethyl)-N3,N3-bis[3-(thiophen-2-ylmethylammonio)propyl]propane-1,3-diammonium hexafluoridosilicate methanol trisolvate

In the title compound, C24H40N4S34+·2SiF62−·3CH3OH, the central tertiary amine function is protonated and is connected to three thiophen-2-ylmethylamino-n-propyl groups, forming the arms of a T-shaped cation that has two pockets. Each arm contains one protonated secondary amine function, and each pocket is occupied by one SiF62−anion bondedviatwo N—H...F interactions with the protonated amine group on the middle arm, while two methanol solvent molecules are N—H...O hydrogen-bonded with the other secondary protonated amine groups on the side arms. Weak O—H...O and O—H...F hydrogen bonds between the solvent molecules and between the solvent molecules and the anions, respectively, are also observed. All three thiophene groups in the arms are disordered over two sets of sites, with occupancy ratios of 0.828 (3):0.172 (3), 0.910 (2):0.090 (2) and 0.890 (3):0.110 (3).

Functionalization of porphyrins: towards the synthesis of bifunctional chelates for bismuth coordination

We report the condensation of 3-chloromethyl-benzoyl chloride with two atropisomers ααββ and αβαβ of meso-5,10,15,20-tetrakis-(2-amino)phenylporphyrin (TAPP), followed by the reaction of the anion of either cyano-acetic acid ethyl ester or (4-nitro-phenyl)-acetic acid ethyl ester to prepare various pre-organized strapped porphyrins. These two reagents were selected as both allow the easy formation of the anion in the α position of the ester group while their electron-withdrawing group (EWG) can be further transformed in a reactive functional group. In the ααββ series, this reaction leads to three isomeric porphyrins differing only by the location of their ethoxycarbonyl groups, oriented either towards the center of the porphyrin or maintained outside of the cavity. In the αβαβ series, as expected, a single porphyrin is obtained in which both straps bear an ethoxycarbonyl group, precursor of a hanging carboxylic function and a cyano or a 4-nitro-phenyl group, which can be reduced to an amine function, suitable for the coupling on a biomolecule.