Synthesis of disubstituted 1,2-dioxolanes, 1,2-dioxanes, and 1,2-dioxepanes

A route to cyclic peroxides containing 1,2-dioxolane, 1,2-dioxane or 1,2-dioxepane rings is described. These compounds present simpler structures related to the bicyclic core of stolonoxides, metabolites with marked cytotoxicity against several mammalian tumor cell lines, isolated from the marine tunicate Stolonica socialis. The key synthetic step consists in the intramolecular Michael addition of a secondary hydroperoxide group to an α,β-unsaturated ester.     

The crystal and molecular structure of 1,2-diphenyl-1,2-diphospholane-1,2-disulphide

The crystal and molecular structure of 1,2-diphenyl-1,2-diphospholane-1, 2-disulphide has been determined from three dimensional X-ray diffraction data

by Patterson and Fourier techniques. The structure has been refined by full matrix least squares methods to a final R value of 0.055 based on 1733 observed reflexions. The unit cell is orthorhombic, space group P2₁2₁2₁, with dimensions a = 13.867 Å, b = 12.379 Å and c = 9.312 Å (all ± 0.003 Å), and contains 4 molecules. The PP bond length of 2.253 ± 0.002 Å is similar to that in several diphosphine disulphides and phosphorus sulphides, and indicates the absence of any π bonding in the PP bond.     

Synthesis of optically pure 1,2-diaryl- and 1,2-alkylaryl-1,2-amino sulfides

[reaction: see text] The reactions of the lithium (S)-alpha-(methylthio)-2-(p-toluenesulfinyl)benzyl carbanion with (S)-N-p-tolylsulfinyl aldimines evolve in a completely stereoselective manner providing a one-step synthesis of enantiomerically pure anti-1,2-disubstituted 1,2-amino sulfide derivatives.     

Macrocycles with 1,2-dicyano-1,2-dithioethene units

Abstract

The new unsaturated macrocyclic tetrathioethers (Z,Z)-4 (n = 0), (Z,Z)-5 (n = 1), (Z,Z)-6 (n = 2) and (Z,Z)-7 (n = 3) were synthesized by the cyclization of (Z)-disodium-1,2-dicyanoethene-1,2-dithiolate (Z)-3 with ω,ω'-dibromoalkanes BrCH₂CH₂(CH₂)nCH₂Br (n = 0;1;2;3) on refluxing in dioxane in yields up to 15%. By reaction of the dithiolate (Z)-3 with 1,3-dibromopropane the unsaturated hexathioether (Z,Z,Z)-6 was also obtained. By the cyclization of dithiolate (Z)-3 with 1,5-dibromopentane and 1,6-dibromohexane the (Z,E)- and (E,E)-isomers, respectively, were formed in addition to the (Z,Z)-isomers. The (E,E)- and (Z,E)-isomers are photochemically convertable to the corresponding themodynamically more stable (Z,Z)-isomers by irradiation with UV-light. The (E,E)-isomers can be synthesized in a straightforward manner using the (E)-disodium-1,2-dicyanoethene-1,2-dithiolate (E)-3. Crystal structures of (Z,Z)-5, (Z,Z)-6, (E,E)-6, (Z,E)-7 and (E,E)-7 are reported.     

Reducing properties of 1,2-diaryl-1,2-disodiumethanes

1,2-Diphenyl- and 1-phenyl-2-(2-pyridyl)-1,2-disodiumethane efficiently dehalogenate vic-dibromoderivatives, affording the corresponding alkenes. The reaction proceeds rapidly, under mild conditions and is tolerant of a variety of functional groups (alcohol, carboxylic acid, ester and amide). This procedure was successfully extended to similar vic-disubstituted compounds.     

1,2-HOIQO--a highly versatile 1,2-HOPO analogue

A cyclic, bidentate hydroxamic acid binding unit based on an isoquinoline scaffold has been utilized for the synthesis of a hexadentate tripodal ligand based on the TREN backbone. This prototype for a new class of multidentate chelators forms mononuclear iron(III) complexes and one-dimensional coordination polymers with lanthanide(III) cations. The latter has been determined by single-crystal X-ray analysis of the cerium species. The solid-state structure in the monoclinic space group P2(1)/c (C(36)H(34)CeN(7)O(11), a = 12.341(2) A, b = 26.649(4) A, c = 10.621(2) A, alpha = gamma = 90 degrees, beta = 96.753(3) degrees, V = 3468.6(9) A3, Z = 4) exhibits a trigonal-dodecahedral environment around the cerium cation. The proof of concept for the versatility of the new scaffold has been shown by the modification of the crucial precursor 3-carboxyisocoumarin through electrophilic aromatic substitutions to yield the corresponding chlorosulfonated and nitrated analogues.     

The synthesis of 1,2-diacetyl- and 1,2-diethylferrocenes

A method is described for the preparation of 1,2-diacetylferrocene, in which ferrocene is acetylated with acetyl chloride in the presence of AlCl₃ in methylene chloride. Addition of the ferrocene to an excess of the acetylation mixture over a prolonged period was found to be most favourable. The 1,2-diacetylferrocene formed proved to be free of the 1,3-isomer. It was reduced with LiAlH₄/AlCl₃ to 1,2-diethylferrocene.     

One-pot synthesis of rac-1,2-diphenylethylene-1,2-diamine

Russian Chemical Bulletin -