Chain-bridged, synthesis

Pariser-Parr-Pople calculations, 72 calculations of thiazolocyanines, 73 of thiazolium salts, 31 Pentamethine thiazolocyanines, chain-bridged, synthesis of. 58 cleavage of, 63 nomenclature of. 26 synthesis of, 56... 

Chain-bridged cyanines, see Thiazoio-cyanines, chain-bridged Chain-bridged thiazolocyanines, see Thia-zolocyanines, chain-bridged Charge distribution, on methine chain, 72 2-Chloro-3,3-dimethylindolenine, in synthesis of pentamethine thiazolocyanines. 56... 

Ethyl-2-methyi-4-phenylthiazolium salts, on hydrobase of, 39 3-Ethyi-5-methyl-2-(p-dimethylamino-styiyl) thiazolium iodide, 29 Ethyl orthoformate, condensation with, thiazolium salts, 49 in synthesis of. chain-bridged thiazolocyanines, 58 thiazolocyanines. 58... 

Pyrroloj2,1 -b) thiazole, formation of, 36 as intermediate for dyes, 36 in synthesis of chain-bridged thiazolocyanines, 58... 

Thiazolo] 2,3fl) indole, in synthesis of chain-bridged thiazolocyanines, 58 Thiazolosemicyanines, tables of, 119 Thiazolostyryl dyes, tables of, 107 Thieno [ 2,3d ] thiazole. 30 2-[2-Thienyl) selenazole, formylation in 5-position, 239... 

A. Jacobi, D. Seebach, How to Stabilize or Break P-Peptidic Helices by Disulfide Bridges Synthesis and CD Investigation of P-Peptides with Cysteine and Homocysteine Side Chains Helv. Chim. Acta 1999, 82, 1150- 1172. 

Recently, Wynne and co-workers [1,2] and Marks and co-workers [3-6] described the synthesis and characterization of inorganic-organic polymers, in which a metallic or pseudometallic element alternates with a linear-chain bridging atom, like oxygen or fluorine. The metallic or pseudometallic element is usually the centr atom of a phthalocyanine system, and the bridge-stacked polymeric structure is rigid. These derivatives are electrical conductors after iodine oxidation. 

Tricyclic Antidepressants. Imipramine [50-49-7] (32), which was the first tricycHc antidepressant to be developed, is one of many useful psychoactive compounds derived from systematic molecular modifications of the antihistamine prometha2ine [60-87-7] (see Histamine and histamine antagonists). The sulfur atom of prometha2ine was replaced with an ethylene bridge and the dimethylamino group attached to an / -propyl group, rather than to an isopropyl one, of the side chain. The actual synthesis of (32) is typical of the compounds in this class (37). 

Warshawsky and coworkers have recently reported the synthesis of a class of compounds which they call polymeric pseudocrown ethers . A chloromethylated polystyrene matrix is used here as in 6.6.2, but instead of adding a crown to the backbone, a strand of ethyleneoxy units is allowed to react at two different positions on the chain, thus forming a crown. Such systems must necessarily be statistical, and the possibility exists for forming interchain bridges as well as intrachain species. Nevertheless, polymers which could be successfully characterized in a variety of ways were formed. A schematic representation of such structures is illustrated below as compound 30. ... 

These steps can be repeated to add one amino acid at a time to the growing chain or to link two peptide chains together. Many remarkable achievements in peptide synthesis have been reported, including a complete synthesis of human insulin. Insulin is composed of two chains totaling 51 amino acids linked by two disulfide bridges. Its structure was determined by Frederick Sanger, who received the 1958 Nobel Prize in chemistry for his work. 

It is well known that native collagen containes tripeptide sequences, which alone are not capable of building up a triple helix (e.g. Gly-Pro-Leu, Gly-Pro-Ser) when they exist as homopolypeptides. The synthesis of threefold covalently bridged peptide chains opens up the possibility of investigating the folding properties of such weak helix formers, because the bridging reduces the entropy loss during triple-helix formation and thereby increases the thermodynamic stability of the tertiary structure. Therefore, we have... 

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