in this paper we focus on a special class of commutative local‎ ‎rings called spap-rings and study the relationship between this‎ ‎class and other classes of rings‎. ‎we characterize the structure of‎ ‎modules and especially‎, ‎the prime submodules of free modules over‎ ‎an spap-ring and derive some basic properties‎. ‎then we answer the‎ ‎question of lam and reyes about strongly oka ideals fam...

Treatment of benzanthrone (1) with biphenyl-2-yl lithium leads to the surprisingly stable enol 4, which is converted by dehydrogenation into the benzanthrone derivative 7. Under acidic conditions 4 isomerises to the spiro compound 11 and the bicyclo[4.3.1]decane derivative 12. Furthermore, the formation of 7 and the hydrogenated compound 13 is observed. A mechanism for the formation of the reac...

[2+2] Cycloadditions of methylene exo-glycal derivatives with chlorosulfonyl isocyanate and dichloroketene were studied in detail, investigating the effect carbohydrate moiety, protecting groups as well reaction temperature on yields transformations. These reactions gave new anomeric spiro-β-lactam spiro-cyclobutanone derivatives, whose structure was established by 1D 2D NMR MS experiments. The...

The development of multicomponent reactions (MCRs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. A comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...

In the title compound, C22H20ClN3O4, the central pyrrolidine ring adopts an envelope conformation on the N atom. The indolinone systems are individually roughly planar, with maximum deviations from their mean planes of 0.130 Å for the spiro C atom of the indolinone unit and 0.172 Å for the carbonyl C atom of the 5-chloro-1-methyl-indolinone unit. They make dihedral angles of 77.7 (8) and 86.1 (...

The base-promoted reaction of 3-sulfolene with bis-vinyl ketones was shown in earlier work to proceed through a γ-1,2 addition/anionic oxy-Cope cascade; a subsequent treatment with base induced a second γ-1,2 addition to provide a [3.3.0] bicyclic framework that our group then exploited in the design of rigidified enzyme inhibitors for influenza neuraminidase. Out of a desire to expand the rang...

In the isoquinoline ring system of the title mol-ecule, C(18)H(20)N(2)O(5), the N-heterocyclic ring is in a half-boat conformation. The dioxa-2-aza-spiro ring is essentially planar, with a maximum deviation of 0.029 (1) Å, and makes a dihedral angle of 30.63 (5)° with the benzene ring. The mol-ecular structure is stabilized by a weak intra-molecular C-H⋯O hydrogen bond, which generates a S(6) r...

In the title compound, C(31)H(22)F(3)NO(2), the pyrrolidine and cyclo-pentane rings within the dihydro-indene ring system are in envelope conformations, with the N atom and the spiro-C atom at the flap, respectively. An intra-molecular C-H⋯O hydrogen bond forms an S(8) ring motif. The mean plane through the pyrrolidine ring [r.m.s. deviation = 0.179 (2) Å] makes dihedral angles of 86.30 (13), 8...

The aminoglycosidic antibiotic hygromycin B presents a peculiar chemical structure, characterized by two sugar rings joined via a spiro connection. The Cu(ii) complex of hygromycin B in water solution was characterized by (1)H-NMR, UV-Vis, EPR and CD spectroscopy, combined with potentiometric measurements. The spin-lattice relaxation enhancements were interpreted by the Solomon-Bloembergen-Morg...