The lithium enolate of (2S,3S,5S,6S)-dimethoxy-2,3-dimethyl-1,4-dioxane-5,6-dithiocarboxylate undergoes stereoselective mono- and/or dialkylations to afford two new stereogenic centers. The alkylation products obtained possessed a cis stereochemistry, which was confirmed by the synthesis of natural 4'-O-methylpiscidic acid dimethyl ester .

Wine stability considerations can be classified as: microbiological, protein, tartrate, red wine oxidative and color, white wine oxidative and color, and metals. The problems of producing stable, highly palatable products are of concern to every vintner. The days when wineries can release wines to the public with physical instabilities and still compete has long past. It is essential that every...

Z. Naturforsch. 53 b, 788-791 (1998); received May 25, 1998 Carnitine, Tartrate, Hydrogen Bonds L-Carnitine forms a salt-like 2:1 adduct with L-tartaric acid which crystallizes in the orthorhombic space group P212121 with Z = 4 formula units in the unit cell. The lattice is composed of an L-tartrate dianion and two crystallographically independent L-carnitinium cations. The two cations show onl...

Catalytic 5-component cascade chemistry provides an effective stereo- and regioselective route to novel multi-functional Z,Z-bisallylamines. The process, which is capable of considerable further extension, utilises ammonium tartrate as a novel ammonia source which avoids the use of ammonia gas or aqueous ammonia.

Interactions during cell adhesion to external surfaces may reach the level of discrimination of molecular chirality. Cultured epithelial cells interact differently with the [011] faces of the (R,R) and (S,S) calcium tartrate tetrahydrate crystals. In a modified version of the classical Pasteur experiment, the enantiomorphous crystals were sorted out from a 1:1 mixture by the selective adhesion ...

Amphiphile supramolecular assemblies result from the cooperative effects of multiple weak interactions between a large number of subcomponents. As a result, prediction of and control over the morphologies of such assemblies remains difficult to achieve. Here, we described the fine-tuning of the shape, size, and morphology transitions of twisted and helical membranes formed by non-chiral dicatio...

In the title compound, 2C(5)H(8)N(3) (+)·C(4)H(4)O(6) (2-)·H(2)O, the two cations are essentially planar [maximum deviations = 0.023 (1) and 0.026 (1) Å]. In one of the cations, the protonated N atom and one of the amino group H atoms are hydrogen bonded to one of the carboxyl groups of the dianion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. In the crystal structu...

In the title compound, {[Zn(C(4)H(4)O(6))(H(2)O)]·2H(2)O}(n), the l-tartrate ligands adopt μ(4)- and μ(2)-coordination modes. The Zn(II) atom adopts an octa-hedral geometry and is chelated by two kinds of l-tartrate ligands through the hydr-oxy and carboxyl-ate groups and coordinated by one unchelating carboxyl-ate O atom and one water mol-ecule. In the crystal, the l-tartrate ligands link the ...

A homochiral diamond framework was obtained by using a secondary building unit (SBU) comprising an oxo-cluster containing 4Fe(III) and 3Mn(II) ions supported by Sb(3)O tartrate scaffolds. A fully protonated tetratopic cation, tetrakis(4-pyridyloxymethylene)methane (TPOM), acts as a template to arrange the clusters on a diamond lattice.