The absolute configuration of 3-benzoyl-4-hy-droxy-6,6-dimethyl-1,5,7-tris-(3-methyl-but-2-en-yl)bicyclo-[3.3.1]non-3-ene-2,9-dione, C(33)H(42)O(4), isolated from Hypericum hypericoides, has been determined. The previous study [Xiao et al. (2007 ▶). J. Nat. Prod.70, 1779-1782] gave only the established relative configuration. The three stereogenic centers are now established as 1R, 5R and 7S on...

The title hydrated salt, C(21)H(17)N(2)O(3) (+)·Cl(-)·H(2)O, exhibits disorder in one of the furan rings. The major and minor components have a refined occupancy ratio of 0.844 (19):0.156 (19). The structure displays intermolecular hydrogen bonding involving the water molecule and the chloride anion. Close intermolecular C-H⋯Cl and C-H⋯(furan ring) inter-actions complete the hydrogen bonding.

All non-H atoms of the title compound, C(7)H(7)NO(2), are nearly coplaner, the r.m.s. deviation being 0.0087 Å. In the crystal, the partially overlapped arrangement and the face-to-face distance of 3.466 (17) Å between parallel pyridine rings of neighboring mol-ecules indicates the existence of π-π stacking. Inter-molecular O-H⋯N hydrogen bonding and weak C-H⋯O hydrogen bonding are present in t...

The title compound, C(17)H(24)NO(5)S(+)·C(18)H(13)O(8) (-), is the key inter-mediate during the preparation of lesatropane [systematic name (1R,3S,5R,6S)-6-acetoxy-3-(4-methylphenylsulfonyloxy)tropane], a potential anti-glaucoma agent. The tertiary N atom of the tropane ring is involved in inter-molecular N-H⋯O hydrogen bonding, and the carboxylate groups are involved in inter-molecular O-H⋯O h...

The title compound, C(10)H(10)N(2)O(2)·H(2)O, is dimerized by inversion-related inter-molecular N-H⋯O hydrogen bonding. There is an intra-molecular N-H⋯O bond, resulting in a six-membered ring. Each dimer inter-acts with other dimers through hydrogen bonding with water mol-ecules. The water mol-ecules are linked to each other in a stair-like chain, thus generating two-dimensional polymeric stri...

Crystallographic data analyses indicate that three types of prolinium cations, along with two types of hydrogen bonding, produce and stabilize the helical structure of triprolinium 12-phosphomolybdate. There are similarities between this organic-inorganic compound and peptides/proteins. The stronger “conventional” hydrogen bonds and the less common C-H…O attractions play critical roles in gener...

Crystallographic data analyses indicate that  three types of prolinium cations, along with two types of hydrogen  bonding,  produce and stabilize the helical structure of  triprolinium 12-phosphomolybdate. There are similarities between this organic-inorganic compound and peptides/proteins. The stronger “conventional” hydrogen bonds and the less common C-H…O attractions play critical roles in g...

The structural, electronic, bonding and magnetotropic properties of inclusion compounds formed upon interaction of cerium monoxide, CeO, with buckybowls (quadrannulene, C(31)H(16), corannulene, C(20)H(10) and sumanene, C(21)H(12)) have been investigated by DFT calculations. For the sake of comparison the structural, electronic, bonding and magnetotropic spectroscopic properties of related annul...

background: failures such as marginal discoloration and composite chipping are still the problems of tooth-colored restorations on the substrate of enamel and porcelain, which some of these problems are consequently as a result of failures in the bonding layer. using fi lled resin has been recently introduced to increase the bond strength of this layer. the aim of this study was to compare the ...

Hydrogen bonds (H-bonds) formed between nucleobases play an important role in the construction of various nucleic acid structures. The H-donor and H-acceptor pattern of a nucleobase is responsible for selective and correct base pair formation. Herein, we describe an 8-thioadenine nucleobase analogue and an 8-thiohypoxanthine nucleobase analogue with a photolabile 6-nitroveratryl (NV) group on t...