The reaction between Bu(n)Li in benzene and the solid polystyrene support PS-C6H4CH2NH2 leads to a lithiated species that can be represented as PS-C6H4CH2NHLi(LiBu)x, where x approximately 4, which is active in the ring-opening of the cyclic esters L-lactide, rac-lactide, and 2,5-morpholinediones. With approximately 10 eq of these monomeric six-membered rings and with heating, cyclic esters (Me...

In the title compound, C(24)H(22)N(2)O(4)S, the central pyrimidine ring is significantly puckered, assuming a conformation inter-mediate between a boat and a screw boat. The nearly planar thia-zole ring (r.m.s. deviation = 0.0258 Å) is fused with the pyriamidine ring, making a dihedral angle of 9.83 (7)°. The carboxyl group is in an extended conformation with an anti-periplanar orientation with...

In the title compound, C28H22N2O8S, the carbazole ring system is roughly planar, with a maximum deviation of 0.084 (3) Å for the C atom connected to the 4,5-dimeth-oxy-2-nitro-phenyl ring. The dihedral angle between the carbazole system and the dimeth-oxy-substituted nitro-phenyl ring is 57.05 (10)°. The aldehyde C atom deviates by 0.164 (5) Å from its attached carbazole ring system. The mol-ec...

In the title compound, [Fe(C(5)H(5))(C(17)H(15)N(2)S)], the cyclo-penta-dienyl (Cp) rings are almost parallel and essentially eclipsed, with a dihedral angle between the Cp ring planes of 0.807 (11)°. The Fe atom is slightly closer to the substituted cyclo-penta-dienyl ring, with an Fe-centroid distance of 1.6510 (8) Å, compared with 1.6597 (8) Å for the unsubstituted ring. The bridging unit be...

We explore the subrings in trigonometric polynomial rings and their factorization properties. Consider the ring S′ of complex trigonometric polynomials over the field Q(i) (see [11]). We construct the subrings S′ 1, S′ 0 of S′ such that S′ 1 ⊆ S′ 0 ⊆ S′. Then S′ 1 is a Euclidean domain, whereas S′ 0 is a Noetherian HFD. We also characterize the irreducible elements of S′ 1, S′ 0 and discuss amo...

let $r$ be a ring and $m$ a right $r$-module with $s=end_r(m)$. a module $m$ is called semi-projective if for any epimorphism $f:mrightarrow n$, where $n$ is a submodule of $m$, and for any homomorphism $g: mrightarrow n$, there exists $h:mrightarrow m$ such that $fh=g$. in this paper, we study sgq-projective and$pi$-semi-projective modules as two generalizations of semi-projective modules. a m...

In the title compound, C(10)H(11)NO(3)S, the benzisothia-zole ring system is almost planar [maximum deviation = 0.030 (1) Å for the S atom]. The isoprop-oxy group is almost in the plane of the benzisothia-zole ring system [N-C-O-C = 4.5 (2)°] with one of its methyl groups in an anti-periplanar orientation relative to the benzisothia-zole ring system [C-C-O-C = -162.0 (2)°].

In the title compound, C(29)H(26)N(2)O(3)S, the central imidazolidine ring adopts an envelope conformation with the N atom bearing the benzyl ring at the flap. The S atom has distorted tetra-hedral geometry. The benzyl and tosyl rings are oriented at a dihedral angle of 52.1 (1)°. The phenyl rings connected to the imidazolidine ring form a dihedral angle of 28.7 (1)°.

In the title compound, C(16)H(13)NO(3)S, the sulfonyl-bound phenyl ring forms a dihedral angle of 84.17 (6)° with the indole ring system. An intra-molecular C-H⋯O hydrogen bond generates an S(6) ring motif. The crystal structure exhibits weak inter-molecular C-H⋯O hydrogen bonds and π-π inter-actions between the five- and six-membered rings of the indole group [centroid-centroid distance = 3.68...

In the title compound, C(16)H(9)F(4)N(3)O(2), the dihedral angle between the aromatic ring systems is 4.10 (14)° and a bifurcated intra-molecular N-H⋯(O,F) hydrogen bond generates an S(6) ring for the O-atom acceptor and an S(5) ring for the F-atom acceptor. A short C-H⋯O conact also occurs. In the crystal, mol-ecules are linked by C-H⋯O inter-actions.