L. R. Imaeva

CHROMIUM(II) CHLORIDE AS A HIGHLY SELECTIVE C(5)-DECHLORINATING AGENT FOR FUNCTIONALIZED 2,3,5-TRICHLOROCYCLOPENT-2-EN-1-ONES

Abstract(±)-2,3,5-Trichloro-4,4-ethylenedioxy- and (±)-5-allyl(allenyl)-2,3,5-trichloro-4,4-dimethoxycyclopent-2-en-1-ones undergo regioselective reductive C(5)-dechlorination under the action of CrCl2 to give the corresponding 2,3-dichlorocyclopentenones.

A novel variant for the preparation of allyl(propargyl) vinyl ethers and their rearrangement into 5-allyl(allenyl)-5-chloro-2-(2-hydroxyethyloxy)-cyclopent-2-ene-1,4-diones

Reactions of 1,2-di- and 1,2,4-trichloro-6,9-dioxaspiro[4.4]non-1-en-3-ones with sodium 2-propenoxide or sodium 2-propynoxide afforded the corresponding 3-allyloxy or 3-propynyloxycyclopentenones, as well as the products of their subsequent thermal [3,3]-sigmatropic rearrangement.

Prostanoids: LXXV. Synthesis of 4-Hydroxy-2-octyl-2-cyclopentenone

The title compound was synthesized by AdNE addition of n-octyl cuprate to 2,3-dichloro-4,4-ethylenedioxy-2-cyclopentenone, followed by alcoholysis and reduction with NaBH4.

(±)-2,3,5-trichloro-4,4-ethylenedioxycyclopent-2-en-1-one and its 5-allyl-substituted derivative in conjugated 1,4-addition with dimethyldilithium cyanocuprate

Abstract(±)-2,3,5-Trichloro-4,4-ethylenedioxycyclopent-2-en-1-one reacts with Me2CuCNLi2 to give depending on conditions the corresponding 3-methyl substituted cyclopentenone (AdNE adduct) or a mixture of unsaturated acyclic acids formed as the result of abnormal cleavage reaction of C(1)−C(2) bond in the trichorocyclopentenone. Reactions of conjugated 1,4-addition of Me2CuCNLi2 to (±)-5-allyl-2,3,5-trichloto-4,4-dimethoxycyclopent-2-en-1-one lead to products of replacement of vinylic Cl atom at C(3) by Me group and those of C(5)-dechlorination.

Synthesis and properties of (+)-2-decarboxy-2-methyl-20-nor-19-carboxyprostaglandin F2 a and its 15Β-epimerideand its 15Β-epimeride

Discovery of the structure of primary prostaglandins (PGs) was followed by a period of their extensive characterization [1,2]. It was found that, from the application standpoint, natural PGs possess a number of undesired properties such as instability, rapid metabolism, wide spectrum of physiological activities, etc. The need for PG preparations acceptable for clinical use has stimulated work on the synthesis and characterization of PG analogs. In a short period of time a number of compounds, more stable with respect to metabolism and capable of selective and prolonged action, were selected among the modified prostanoids, and highly efficient drugs based on them were developed [3 5]. Analysis of data available in the literature allowed us to formulate several principles of strategy for the search and design of PG analogs. 2 A principal condition is that the chemical modification of side chains and ring fragments of molecules must be performed so that the structure of the PG analogs would be topologically equivalent to the stereochemical structure of the initial PG. This implies the presence of (i) a Cwcarboxy function or its equivalent in the s-chain of the modified molecule, (ii) a C 8 C12 ring fragment, and (iii) a C~3 C20 alkane segment (to-chain). All these parts of the PG molecule may possess functionalities of different types. This approach is obviously explained by the desire to block the probable pathways of metabolic decay of the PG analog, and to retain as far as possible its compatibility with the PG re-. ceptors. These principles are consistently implemented in practice, as confirmed by a comparative analysis, e.g., of the structure of natural PGE2 (I) and some modified prostanoids (II IV) used in clinical practice [5].