the synthesis of cis-n-[a-carbobenzyloxy-b-(p-hydroxyphenyl)ethyl]-3-phthalimido-4-styryl-2-azetidinone is described. we have found that the electron-rich schiff bases can afford the cis-b-lactam ring even in the presence of the free hydroxyl functions. the mechanisms of cis and trans-b-lactam ring formation are discussed. the discussions are consistent with the recent publications.

The title compound, C(16)H(12)N(2)O(6)·2C(3)H(7)NO, lies across a crystallographic inversion centre which is situated at the midpoint of the central N-N bond. The substitution at the C=N bond adopts a trans configuration and it is essentially coplanar with the benzene ring [N-C-C-C torsion angles = -173.9 (4) and 6.4 (6)°]. All torsion angles involving non-H atoms are close to 180°. Intra-molec...

In the title 1:1 adduct, C(6)H(6)N(2)O·C(11)H(8)O(2), the amide group is slightly twisted out of the plane of the aromatic ring, with a C-C-C-N torsion angle of 25.11 (19)°, whereas the carb-oxy-lic acid group is approximately coplanar with the bicylic ring system, with a C-C-C-O torsion angle of 10.9 (2)°. The amide groups from two isonicotinamide mol-ecules form a dimer via N-H⋯O hydrogen bon...

In this paper, we consider a finite, torsion-free module E over Gorenstein local ring. We provide sufficient conditions for to be of linear type and the Rees algebra R ( ) Cohen-Macaulay. Our results are obtained by constructing generic Bourbaki ideal I exploiting properties residual intersections .

The title compound, C(18)H(30)N(4)O(2), contains two tert-butyl urea groups, each connected to a benzene ring though a methyl-ene group. One of the groups occupies a position almost normal to the aromatic plane with a C-N-C-C torsion angle of -94.4 (4)°, while the other is considerably twisted from the ring with a C-N-C-C torsion angle of -136.1 (4)°. In the crystal, pairs of mol-ecules are con...

In the title compound, C(13)H(10)N(2)O(5)S, the N-C bond in the C-SO(2)-NH-C segment has gauche torsion angles with respect to the S=O bonds. The conformation between the N-H bond and the ortho-nitro group in the sulfonyl benzene ring is syn. The mol-ecule is twisted at the S-N bond with a torsion angle of -63.4 (2)°. The sulfonyl benzene ring is tilted by 77.1 (1)° relative to the -SO(2)-NH-C-...

In the title compound, C17H11Cl2NO, the dihedral angle between the planes of the naphthalene ring system and the benzene ring is 28.88 (11)°. The main twist in the mol-ecule occurs about the N-Cb (b = benzene ring) bond, as indicated by the C=N-Cb-Cb torsion angle of 31.0 (4)°. An intra-molecular O-H⋯N hydrogen bond closes an S(6) ring. In the crystal, inversion dimers linked by pairs of very w...

We describe the effects of geometric torsion on the coherent motion of electrons along a thin twisted quantum ring. The geometric torsion inherent in the quantum ring triggers a quantum phase shift in the electrons' eigenstates, thereby resulting in a torsion-induced persistent current that flows along the twisted quantum ring. The physical conditions required for detecting the current flow are...

In the title compound, C(23)H(17)ClN(2)O(3), the quinazoline fused-ring system, including the ring-bound carbonyl-O and methyl-C atoms, is close to being planar (r.m.s. deviation = 0.044 Å) and is essentially orthogonal to both the 2-tolyl ring [dihedral angle = 89.51 (8)°] and to the ester group [the C-O-C-C torsion angle = -103.69 (16)°]. The carboxyl-ate group is almost coplanar with the ben...

In the mol-ecule of the title compound, C(18)H(16)F(2)N(4)O(2), the 1,2,4-triazole ring forms dihedral angles of 3.6 (2) and 14.9 (6)° with the 4-difluoro-meth-oxy-substituted benzene ring and the 2,3-dimethyl-substituted benzene ring, respectively. The OCHF(2) group is twisted away from the plane of the benzene ring, as shown by the C-O-C-C torsion angle of 145.8 (2)°. The conformation is stab...