Tartrate structure

Chemical Name 2,3,4,9-tetrahydro-2-methyl-9-phenyl-1 H-indeno[2,1, c] pyridine tartrate Common Name 2-methyl-9-phenyl-2,3,4,9-tetrahydro-Tpyridindene tartrate Structural Formula CcH, ... 

Common Name Dihydrocodeine tartrate Drocode Hydrocodein tartrate Structural Formula ... 

Archer, owing to very unfortunate coincidences, had mistaken acid potassium tartrate for the acetylamino acid. Goldfarb et al. prepared authentic 5-acetylamino-2-thiophenecarboxylic acid, mp 230 232°C (methyl ester, mp 171-171.5°C ethyl ester, mp 161°C), through reduction of 5-nitro-2-thiophenecarboxylic acid with Raney nickel in acetic anhydride and proved the structure by Raney nickel desulfurization to 8-aminovaleric acid. They also confirmed that the acid mp 272-273°C (methyl ester, mp 135-136°C ethyl ester, mp 116-117°C) is 4-acetylamino-2-thiophenecar boxy lie acid as originally stated by Steinkopf and Miiller. The statement of Tirouflet and Chane that the acid obtained upon reduction and acetylation of 5-nitro-2-thiophenecarboxylic acid melts at 272°C must result from some mistake as they give the correct melting point for the methyl ester. 

The reason for the efficient epoxidation of explicitly allylic alcohols with this system can be found in the strong associative interactions occurring between the substrate and the catalyst. The [Ti(tartrate)(OR)2]2 dimer 1, which is considered to be the active catalyst in the reaction, will generate structure 2 after the addition of... 

Figure 6.1 Proposed structure for the titanium tartrate complex (1) and its transformation after addition of reagents (e. g., TBHP and olefin), forming (+)-2.

The mechanism for such a process was explained in terms of a structure as depicted in Figure 6.5. The allylic alcohol and the alkyl hydroperoxide are incorporated into the vanadium coordination sphere and the oxygen transfer from the peroxide to the olefin takes place in an intramolecular fashion (as described above for titanium tartrate catalyst) [30, 32]. 

A crystal structure of the C02 derivative of (8), K[Co(salen)( 71-C02)], haso been reported in which the Co—C bond is 1.99 A, the C—O bonds are both equivalent at 1.22 A and the O-C-O angle is 132°.125 Carboxylation of benzylic and allylic chlorides with C02 in THF-HMPA was achieved with (8) electrogenerated by controlled-potential electrolysis,126 in addition to reductive coupling of methyl pyruvate, diethyl ketomalonate and / -tolylcarbodiimide via C—C bond formation. Methyl pyruvate is transformed into diastereomeric tartrates concomitant with oxidation to the divalent Co(salen) and a free-radical mechanism is proposed involving the homolytic cleavage of the Co—C bond. However, reaction with diphenylketene (DPK) suggests an alternative pathway for the reductive coupling of C02-like compounds. 

Figure 1.18 STM image (4 nm x 4 nm) showing the 2D cocrystalline structure consisting of an ordered array of 1 1 H-bonded complexes of (R,R)-tartrate and methylacetoacetate species on Ni l 1 1 givingachiral (3 11-3 4) structure. (Adapted with permission from Ref. [62], Copyright 2002, Elsevier.)...

According to El-Mashri et al.,190 the A106 A104 ratio determines the hydration capacity of anodic oxides. Tetrahedral sites are hydrated easily to form a boehmite-like structure, which is known to be composed of double layers of Al-centered octahedra, weakly linked by water molecules to other layers.184 As the oxide formed in H3P04 contains about 70% tetrahedral aluminum bonds, its hydration ability should be higher than that of the oxide formed in tartrate solution. However, this has not been found in practice, which is interpreted by El-Mashri et al. as being due to some reduction of A104 by incorporated phosphate species. 

Solid-state structures of two bismuth tartrate complexes reveal a similar asymmetric unit composed of two tartrate ligands on a bismuth center and are distinguished by replacement of a proton in Bi(H3tar)(H2tar) 3H20 (160) with by an ammomium ion in NH4[Bi (H2tar)2(H20)] H20 (161). The nine-coordinate bismuth environments in each structure are very similar, as illustrated in 48, respectively,... 

Furthermore, Oda et al. pointed out that there are two topologically distinct types of chiral bilayers, as shown in Figure 5.46.165 Helical ribbons (helix A) have cylindrical curvature with an inner face and an outer face and are the precursors of tubules. These are, for example, the same structures that are observed in the diacetylenic lipid systems discussed in Section 4.1. By contrast, twisted ribbons (helix B) have Gaussian saddlelike curvature, with two equally curved faces and a C2 symmetry axis. They are similar to the aldonamide and peptide ribbons discussed in Sections 2 and 3, respectively. The twisted ribbons in the tartrate-gemini surfactant system were found to be stable in water for alkyl chains with 14-16 carbons. Only micelles form... 

Figure 5.46 Schematic representation of helical and twisted ribbons as discussed in Ref. 165. Top Platelet or flat ribbon. Helical ribbons (helix A), precursors of tubules, feature inner and outer faces. Twisted ribbons (helix B), formed by some gemini surfactant tartrate complexes, have equally curved faces and C2 symmetry axis. Bottom Consequences of cylindrical and saddlelike curvatures in multilayered structures. In stack of cylindrical sheets, contact area from one layer to next varies. This is not the case for saddlelike curvature, which is thus favored when the layers are coordinated. Reprinted with permission from Ref. 165. Copyright 1999 by Macmillan Magazines.

The Sharpless epoxidation is a popular laboratory process that is both enantioselective and catalytic in nature. Not only does it employ inexpensive reagents and involve various important substrates (allylic alcohols) and products (epoxides) in organic synthesis, but it also demonstrates unusually wide applicability because of its insensitivity to many aspects of substrate structure. Selection of the proper chirality in the starting tartrate esters and proper geometry of the allylic alcohols allows one to establish both the chirality and relative configuration of the product (Fig. 4-1). 

Crystal structures are available for many (N)4Co-amino acid complexes (Table I). Many of the diastereomers (AS, AS) in the bis-en series have been resolved using classic crystallization (usually via bromocamphor sulfonate, arsenyl-, or antimonyl-tartrate salts) or ion exchange methods (Table II). Reversed-phase ion-pair HPLC, using aryl phosphate or aryl/alkyl sulfonate ion pairing reagents in MeOH/ H20 eluent, has allowed diastereomer separations to be carried out on analytical amounts (28) (Table II). 

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