Crystal structure of N-(2-hy-droxy-eth-yl)-5-nitro-isophthalamic acid monohydrate.

In the title compound, C10H10N2O6·H2O, the carb-oxy-lic acid group and the nitro group are essentially coplanar with the benzene ring [maximum deviation = 0.0264 (9) Å], while the amide group is oriented at a dihedral angle of 9.22 (5)° with respect to the benzene ring. In the crystal, classical O-H⋯O and N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions link the organic mol-ecules and water mol-ecules of crystallization into a three-dimensional supra-molecular architecture.

3,4,6-Tri-O-acetyl-1,2-O-[1-(exo-ethoxy)ethylidene]-ß-D-mannopyranose 0.11-hydrate.

The title compound, C(16)H(24)O(10)·0.11H(2)O, is a key intermediate in the synthesis of 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG), which is the most widely used molecular-imaging probe for positron emission tomography (PET). The crystal structure has two independent molecules (A and B) in the asymmetric unit, with closely comparable geometries. The pyranose ring adopts a (4)C(1) conformation [Cremer-Pople puckering parameters: Q = 0.553 (2) Å, θ = 16.2 (2)° and φ = 290.4 (8)° for molecule A, and Q = 0.529 (2) Å, θ =15.3 (3)° and φ = 268.2 (9)° for molecule B], and the dioxolane ring adopts an envelope conformation. The chiral centre in the dioxolane ring, introduced during the synthesis of the compound, has an R configuration, with the ethoxy group exo to the mannopyranose ring. The asymmetric unit also contains one water molecule with a refined site-occupancy factor of 0.222 (8), which bridges between molecules A and B via O-H···O hydrogen bonds.

Dimethyl 5-amino-2,4,6-triiodo-isophthalate.

The title compound, C(10)H(8)I(3)NO(4), crystallizes with two mol-ecules in the asymmetric unit. The I atoms and the benzene ring plane in the two mol-ecules are approximately coplanar, the I atoms deviating by -0.1631 (1), 0.0704 (1) and -0.0507 (1) Šfrom the mean plane of the benzene ring in one mol-ecule and by 0.1500 (1), -0.0034 (1) and -0.1213 (1) Šin the other. The planes of the ester groups are almost orthogonal to those of the benzene rings in both mol-ecules, forming dihedral angles of 83.5 (3), 76.4 (3), 97.3 (1) and 75.7 (1)°. The mean planes of the benzene rings in two mol-ecules are inclined at 69.8 (3)° with respect to each other. In the crystal, inter-molecular I⋯O inter-actions link the mol-ecules into infinite chains. In addition, N-H⋯O and non-classical C-H⋯O hydrogen bonds are observed.

3,5-Dinitro-benzoyl chloride.

The carbonyl chloride group in the title compound, C(7)H(3)ClN(2)O(5), is disordered over two orientations with occupancies of 0.505 (5) and 0.495 (5). The mol-ecule is approximately planar, the dihedral angle between the carbonyl chloride plane and benzene ring being 9.6 (4)° in the major disorder component and 7.1 (4)° in the minor component. The nitro group at the 5-position is twisted, forming a dihedral angle of 6.7 (4)°. The crystal packing is stabilized by C-H⋯O hydrogen bonds.

Methyl 3-carboxy-5-nitrobenzoate.

The structure of the title compound, C(9)H(7)NO(6), is essentially planar [maximum deviation 0.284 (2)Å] except for the methyl H atoms. The crystal structure is stabilized by asymmetric O-H⋯O hydrogen bonds linking the hydrogen carboxyl-ates into pairs around the inversion centres. There is also π-π stacking of the benzene rings [centroid-centroid distance 3.6912 (12) Å].

2-Isopropoxyphenyl N-methyl-carbamate.

In the title compound, C(11)H(15)NO(3), the mean planes of the carboxamide and isopropyl groups are inclined at 109.9 (1) and 128.7 (2)°, respectively, to the mean plane of the phen-oxy group. In the crystal structure, mol-ecules are stacked along the b axis, without any π-π inter-actions. The stacked columns are linked together by inter-molecular N-H⋯O hydrogen bonds, with an N⋯O distance of 2.842 (2) Å.

4-(4-Ethoxy-benz-yl)-1,3-oxazolidin-2-one.

In the title compound, C(12)H(15)NO(3), the ethoxy-benzyl ring plane forms a dihedral angle of 60.3 (4)° with the mean plane of the oxazolidine ring. The mol-ecules are linked through N-H⋯O hydrogen bonds into a chain running in the b direction.

Isobutyl 3,5-dinitro-benzoate.

In the structure of the title compound, C(11)H(12)N(2)O(6), the mol-ecules are stacked along the b axis without any π-π inter-actions. The stacked columns are linked together by non-classical inter-molecular C-H⋯O inter-actions,. In the molecule, the nitro groups make dihedral angles of 9.4 (5) and 10.3 (5)° with the benzene ring.

1-Carboxy-methyl-2-ethyl-4-methyl-1H-imidazol-3-ium chloride monohydrate.

In the title compound, C(8)H(13)N(2)O(2) (+)·Cl(-)·H(2)O, the methyl C atom of the ethyl group is slightly out of the imidazole plane, with an N-C(ring)-C-C torsion angle of -15.1 (2)°. In the crystal structure, there are strong inter-molecular hydrogen-bonding inter-actions between the solvent water mol-ecule, the free chloride anion and the organic cation, resulting in a two-dimensional supra-molecular network in the ab plane.

Ethyl 3-carb-oxy-5-nitro-benzoate.

In the title compound, C(10)H(9)NO(6), the carb-oxy, ethoxy-carbonyl and nitro groups form dihedral angles of 3.8 (1), 4.5 (1) and 164.8 (1)°, respectively, with the mean plane of the benzene ring. In the crystal structure, mol-ecules lying about inversion centers are linked through O-H⋯O hydrogen bonds. C-H⋯O inter-actions are also present.

A one-step automated high-radiochemical-yield synthesis of 18F-FECNT from mesylate precursor.

2Beta-carbomethoxy-3beta-(4-chlorophenyl)-8-(2-[(18)F]fluoroethyl)nortropane ((18)F-FECNT) is a potential dopamine transporter imaging agent. In this article, a new mesylate precursor was prepared and a one-step automated synthesis of (18)F-FECNT was developed. The mesylate precursor (4) was synthesized from 2beta-carbomethoxy-3beta-(4-chlorophenyl)tropane (1) by N-demethylation, hydroxyethylation followed by mesylation at a total yield of 47%. [(18)F]fluorination was performed by heating 4mg mesylate precursor and K[(18)F] in 1 ml acetonitrile at 90 degrees C for 20 min. The crude (18)F-FECNT was obtained with a radiolabeling yield of 48%. After purification by preparative high performance liquid chromatography (HPLC), the final (18)F-FECNT product was obtained with a radiochemical purity of 98.4% and a decay corrected radiochemical yield of 33+/-9% (and the uncorrected radiochemical yield was 19+/-5%, n=5). The duration of the total procedure was 80-90 min.

Dimethyl 2-nitro-terephthalate.

In the mol-ecule of the title compound, C(10)H(9)NO(6), the two ester groups and the nitro group are inclined at 9.2 (2), 123.3 (6) and 135.2 (5)°, respectively to the mean plane of the benzene ring. In the crystal structure, mol-ecules are stacked along the a axis, without any π-π inter-actions. The stacked columns are linked together by non-classical intermolecular interactions of the type C-H⋯O.

2-(1-Methyl-ethoxy)-5-nitro-phenyl N-methyl-carbamate.

In the title compound, C(11)H(14)N(2)O(5), the nitro group is approximately coplanar with the benzene ring, making a dihedral angle of 4.26 (17)°. The dihedral angle between the methyl-carbamate group and the benzene ring is 72.47 (6)°. There is a strong inter-molecular N-H⋯O hydrogen bond between the N and O atoms from adjacent methyl-carbamate groups, forming a one-dimensional network along the a axis.