Zhi-Hua Mao

Euphorbia factor L8: a diterpenoid from the seeds of Euphorbia lathyris

The title compound [systematic name: (2S*,3S*,4R*,5R*,9S*,11S*,15R*)-5,15-diacetoxy-3-nicotinoyloxy-14-oxolathyra-6(17),12(E)-diene], C30H37NO7, was isolated from the seeds of Euphorbia lathyris. The tricyclic diterpenoid molecule contains an 11-membered ring, a five-membered ring exhibiting an envelope conformation and a three-membered ring. The 11-membered ring is cis-fused with the three-membered ring and trans-fused with the five-membered ring.

1,4-Bis(imidazol-1-yl)benzene-terephthalic acid (1/1).

In the title compound, C12H10N4·C8H6O4, 1,4-bis(imidazol-1-yl)benzene and terephthalic acid molecules are joined via strong O—H⋯N hydrogen bonds to form infinite zigzag chains. Both molecules are located on crystallographic inversion centers. The O—H⋯N hydrogen-bonded chains are assembled into two-dimensional layers through weak C—H⋯O and strong π–π stacking interactions [centroid–centroid distance = 3.818 (2) Å], leading to the formation of a three-dimensional supramolecular structure.

5-Benzyl-2-phenyl-6,8-dihydro-5H-1,2,4-triazolo[3,4-c][1,4]oxazin-2-ium hexa­fluoridophosphate

The title compound, C18H18N3O+·PF6 −, is a chiral bicyclic 1,2,4-triazolium salt which contains four rings, viz. a triazolium, a morpholine and two phenyl rings. Analysis of bond lengths shows that the N—CH—N group in the triazolium ring conforms to a typical three-center/four-electron bond (also known as the Pimentel–Rundle three-center model). The structure is completed by a disordered PF6 − counter-ion [occupancies of F atoms 0.678 (8):0.322 (8)], which interacts with the main molecule through weak intermolecular P—F⋯π interactions.

3,3'-[(tert-Butoxy-carbon-yl)aza-nedi-yl]dipropanoic acid.

The title compound, C11H19NO6, is an important intermediate for the synthesis of cephalosporin derivatives. The N atom is in a planar configuration. In the crystal, molecules are linked into zigzag layers parallel to (100) by O—H⋯O hydrogen bonds.

N-(2-Hydroxy-ethyl)-3,5-dinitro-benzamide.

The title compound, C9H9N3O6, was synthesized by the condensation of methyl 3,5-dinitrobenzoate and 2-aminoethanol. The non-centrosymmetric space group results in the formation of pseudo-chiral helices in the crystal structure, which exhibits a layer packing structure involving intramolecular N—H⋯O and O—H⋯O interactions.

trans-4-Nitro­phenyl 4-(tosyl­oxymeth­yl)cyclo­hexa­necarboxyl­ate

The title compound, C21H23NO7S, is an important intermediate in the synthesis of poly(amidoamine) dendrimers. The cyclohexane ring adopts a chair conformation. The dihedral angle between the two aromatic rings is 69.5 (2)°. The molecules are linked into a zigzag chain along the b axis by C—H⋯O hydrogen bonds.

cis-4-(Tosyl­oxymeth­yl)cyclo­hexa­ne­carboxylic acid

The title compound, C15H20O5S, is an intermediate in the synthesis of novel aminocarboxylic acid derivatives. The cyclohexane ring exhibits a chair conformation. In the crystal structure, adjacent molecules form dimers via O—H⋯O hydrogen bonds.

1-[Bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl]-3-[bicyclo[4.2.0]octa-1(6),2,4-trien-3-yl­methyl]imidazolium hexa­fluoro­phos­phate

In the title compound, C20H19N2 +·PF6 −, the two benzocyclobutene units are essentially planar and they form dihedral angles of 38.0 (2) and 72.7 (2)°, with the central imidazolium ring. In the crystal structure, weak C—H⋯π and π-–π stacking interactions [centroid–centroid distance = 3.742 (2) Å] contribute to the stability of the crystal structure. The PF6 − ion is disordered over two positions with site occupancies of 0.869 (9) and 0.131 (9).

Ethyl 7-amino-1-cyclo-propyl-6-fluoro-8-meth-oxy-4-oxo-1,4-dihydro-quinoline-3-carboxyl-ate monohydrate.

In the title compound, C16H17FN2O4·H2O, the dihedral angle between the heterocyclic ring and the benzene ring is 5.77 (9)°, that between the heterocycle and the ethoxycarbonyl plane is 15.5 (1)°, and that between the heterocyclic ring and the cyclopropane ring is 67.75 (13)°. In the crystal structure, molecules are linked into a ribbon-like structure along the c axis by N—H⋯O and O—H⋯O hydrogen bonds.

3,3′-(1,4-Naphthalene­dimethyl­ene)bis­(1-methyl­imidazolium) diiodide monohydrate

In the title compound, C20H22N42+·2I−·H2O, the two imidazolium rings are twisted away from the central naphthalene plane by 76.6 (1) and 74.5 (1)°. The crystal packing is stabilized by O—H⋯I, C—H⋯O and C—H⋯I hydrogen bonds.