Halina Hajmowicz

Tartaric Acid and its Derivatives. Part 17. Synthesis and Applications of Tartrates

I. Synthesis of Tartrates ..................................................................................... 2 1. Diesters of Tartaric Acid............................................................................... 2 1.1. Esterification of Tartaric Acid (Method A)................................................. 2 a) Inorganic and Organic Acids ................................................................ 2 b) Boron Compounds.............................................................................. 6 c) Heterogeneous Catalysis...................................................................... 7 d) Acyl Chlorides................................................................................... 8 e) Aldehydes ......................................................................................... 8 1.2. Transesterification (Method B)................................................................. 9 1.3. Alkylation (Method C)............................................................................ 9 a) Diazomethane Derivatives ................................................................. 10 b) Alkyl Halides and tertiary Amines ...................................................... 10 c) Alkyl Sulfonates............................................................................... 10 1.4. Oxidation of Dimethyl or Diethyl Fumarate (Method D) ............................ 11 2. Monoesters of Tartaric Acid ........................................................................ 11

Tartaric acid and its O -acyl derivatives. 7. Crystal structure of O-p -anisoyl-D-tartaric acid and its dimethylammonium salt trihydrate

Monoacylated derivatives O-p-anisoyl-d-tartaric acid and its N,N-dimethylammonium salt are synthesized by the partial hydrolysis of O,O′-di-p-anisoyl-d-tartaric acid. Crystal and molecular structures of both compounds have been determined and analyzed. In both of them, some strong and moderate strength [O-H…O] hydrogen bonds exist between the carboxylic units. The intermolecular hydrogen bonds link the adjacent fragments forming infinite one-dimensional chains parallel to the X-axis.

The hydrogen-bonding network in (+)-N-tosyl-L-glutamic acid.

The asymmetric unit of the alpha polymorph of (+)-N-tosyl-L-glutamic acid, C12H15NO6S, contains two independent molecules which differ in conformation. The carboxylic acid groups form an infinite zigzag chain with characteristic R(2)(2)(8) rings running along the b axis. Intermolecular N-H...O and C-H...O contacts mediate the formation of a three-dimensional supramolecular structure described by R(4)(3)(22), R(6)(6)(44) and R(8)(8)(54) graph-set descriptors. Comparison of the extended structure with that of N-(benzenesulfonyl)glutamic acid shows that a subtle difference in the periphery of the molecule, i.e. the replacement of the toluyl group with a phenyl group, can be accompanied by dramatic changes in molecular assembly.

Polymorphism of (+)N-tosyl-L-glutamic acid

It has been shown that polymorphism is the reason for the occurrence of (+)N-tosyl-L-glutamic acid 1 with various melting points. 1 occurs in two crystalline forms: α and β. Form α-1 (prisms) having a melting point of 145–147°C is chemically pure and stable. Form β-1, however, is unstable and is formed as a result of the stabilizing effect of an organic solvent not introduced into the structure of the crystal. At about 125°C the β forms is transformed to the α form. The melting point of the β form depends on the amount and type of solvent contained in the crystal, which, during measurement cannot leave the system.

(2R,3R)-3-O-Benzoyl-N-benzyl-tartramide.

The title compound, C18H17NO6 [systematic name: (2R,3R)-4-benzylamino-2-benzoyloxy-3-hydroxy-4-oxobutanoic acid], is the first structurally characterized unsymmetrical monoamide–monoacyl tartaric acid derivative. The molecule shows a staggered conformation around the tartramide Csp3—Csp3 bond with trans-oriented carboxyl and amide groups. The molecular conformation is stabilized by an intramolecular N—H⋯O hydrogen bond. In the crystal, molecules are linked by O—H⋯O hydrogen bonds between the carboxyl and amide carbonyl groups, forming translational chains along [001]. Further O—H⋯O and N—H⋯O hydrogen bonds as well as weaker C—H⋯O and C—H⋯π intermolecular interactions extend the supramolecular assembly into a double-layer structure parallel to (100). There are no directional interactions between the double layers.