In the crystal structure of the title compound, C(43)H(46)NO(13)·0.5H(2)O, the mol-ecule assumes a U-shaped conformation, the terminal benzene rings being approximately parallel and partially overlapped with each other. The mol-ecule contains eight alicyclic and heterocyclic rings. The cyclo-hexane rings adopt chair conformations, the other three six-membered carbocyclic rings form a bicyclo-[2...

The title compound (delgradine), C(41)H(43)NO(12), is a hetisine-type C(20)-diterpenoid alkaloid, isolated from the roots of Aconitum carmichaeli Debx. In the crystal structure, the mol-ecule assumes an U-shaped conformation, the terminal benzene rings being approximately parallel and partially overlapped with each other. The mol-ecule contains eight alicyclic and heterocyclic rings. Cyclo-hexa...

In the title compound, C(18)H(15)NO(4), the benzene rings form quite different dihedral angles [16.07 (1) and 59.50 (1)°] with the central pyrrole ring, indicating a twisted mol-ecule. Conjugation is indicated between the five- and six-membered rings by the lengths of the C-C bonds which link them [1.462 (3) and 1.477 (3) Å]. The most prominent feature of the crystal packing is the formation of...

substitution of two or four carbon atoms by nitrogen in the corannulene molecule as a carbon nanostructure was done and the obtained structures were optimized at mp2/6-31g(d) level of theory. calculations of the nucleus-independent chemical shift (nics) were performed to analyze the aromaticity of the corannulene rings and its derivatives upon doping with n at b3lyp/6-31g(d) level of theory. re...

Medium sized carbocycles are particularly difficult to synthesize. Ring closing metathesis reactions (RCM) have recently been applied to construct eight-membered carbocycles, but trisubstituted double bonds in the eight-membered rings are more difficult to produce using RCM reactions. In this review, model examples and our own results are cited and the importance of the preparation of suitably ...

The title compound, C(23)H(25)NSi, has an eight-membered silicon-containing heterocyclic ring with an intra-molecular N⋯Si close contact, the transannular distance of which is 2.6294 (18) Å. The resulting geometry about the Si atom is distorted trigonal-bypyramidal, with the N and H atoms occupying apical sites. The dihedral angle between the aromatic rings fused to the eight-membered ring is 6...

Convergent routes to various classes of lactams exploiting the unique radical chemistry xanthates are described. Emphasis is placed on reactions leading by direct cyclization, intermolecular additions alkenes followed ring closure, and furnishing amino esters acids precursors that can be converted into ionic condensations. The possibility modifying existing lactam structures briefly discussed. ...

The asymmetric unit of the title compound, C12H12Cl4O2, contains two crystallographically independent mol-ecules with almost identical conformations (r.m.s. overlay fit for the non-hydrogen atoms = 0.059 Å). In each mol-ecule, the central eight-membered ring has a distorted boat configuration, and two non-planar four-membered rings are fused on either side of the eight-membered ring. A weak C-H...

In the title compound, C(4)H(8)N(5) (+)·Cl(-), a two-dimensional layer packing network is observed in which every chloride anion links three adjacent 2,4-diamino-6-methyl-1,3,5-triazin-1-ium cations by N-H⋯Cl hydrogen-bonding inter-actions, forming 12-membered and eight-membered hydrogen-bonded rings with graph-set motifs R(4) (4)(12) and R(3) (3)(8), respectively. In addition, N-H⋯N hydrogen b...