Dicarboxyl ic acids

Azelaic acid is a naturally occurring dicarboxyl-ic acid (1,7-heptanedicarboxylic acid) that has demonstrated beneficial therapeutic effects in the treatment of acne and several disorders of hyperpigmentation [48]. There are minimal effects on normally pigmented human skin, freckles, senile lentigines, and nevi. The cytotoxic and antiproliferative effects of azelaic acid may be mediated via inhibition of mitochondrial ox-idoreductase activity and DNA synthesis. Disturbance of tyrosinase synthesis by azelaic acid may also influence its therapeutic effects. Azelaic acid can be used as a hypopigmenting agent in patients sensitive to hydroquinone. 

The known adduct (385) of furan and vinylene carbonate, previously used for the synthesis of some cyclitols,256,257 has been transformed into DL-ribose derivatives. After hydroxylation of 385 and subsequent formation of the isopropylidene derivative, the carbonate group was removed by treatment with barium hydroxide, and the resulting diol was cleaved by oxidation with permanganate. Dicarboxyl-ic acid 386 gave, upon treatment with acetic anhydride, cyclic anhydride 387. The reaction of 387 with azidotrimethylsilane produced... 

Azoxydibenzoic Acid or Azoxy benzene-dicarboxyl ic Acid (called Azoxybenzoesaure or Azoxybenzol-dicarbonsaure in Ger), HCX>C-QH4-(N20)-QH,-C00H mw 286.24,... 

Hydrolysis (Section 20.6) Acid anhydrides react with water to yield two carboxylic acid functions. Cyclic anhydrides yield dicarboxyl ic acids. 

Exercise 29-31 Fibers made from aromatic polyamides such as from 1,4-benzene-dicarboxyl ic acid and 1,4-benzenediamine are at least as strong as steel wire with the same ratio of weight to length. What are the structural features of this kind of polyamide that contribute to the strength ... 

Diisopropyl (2S,3S)-2,3-0-isopropylidenetartrate 1,3-Dioxolane-4,5-dicarboxyl ic acid, 2,2-dimethyl-, bis(l-methylethyl) ester, (4R-trans)- (11) (81327-47-1)... 

Cork - cutose, suberin, and suberic acid (1, 6, hexane-dicarboxyl ic acid)... 

H2salphdc Dianionof N,N -phenylenebis(salicyIideneimine)dicarboxyl-ic acid... 

Dicarboxyl ic Acid Halogen Amides, Their So Its and Use in Cross-Linking of Cellulose Fibers Thru Urethone Formation. This problem was investigated by Eckert et al (Ref), who isolated some expl products. For example, N,N,N f -Tetrachloroadipumide or N,N,n n ... 

In order to immobilize the linker, the hydroxy group is either treated directly with a carboxy functionalized resin or is coupled to a dicarboxyl-ic acid spacer on aminomethyl resin. 

ChelidonJc Acid. 4-Oxo-4H-pyrun-2,6-dicarboxyl-ic acid, 4-oxo-l,4-pyran-2,6-dicar boxy lie acid Jerva acid jervasic acid. CjH O mol wt 184-10. C 45.67%, H 2.19%, O 52.14%. Presence In various plants Stransky, Arch. Pharm, 258, 56 (1920) Ramstad, Pharm Acta Helv. 28, 45 (1953). Structure Verkade, jRee. Trav. Chim. 43, 879 (1924). Synthesis Riegel, Reinhard, J. Am Chem. Soc. 48, 1334 (1926) Riegel, Zwilgmeyer, Org. Syn. coll. vol. II, 126 (1943) Toomey, Riegel. J. Org. Chem 17, 1492 (1952). 

Malonic add HOOC-CH2-COOH, a dicarboxyl-ic acid, m.p. 135.6 °C, which has been found in the free form in plants, but is of only sporadic occurrence. At the pH of the cell M.a. is present as its anion (mal-onate), which is a known competitive inhibitor of succinate dehydrogenase in the tricarboxylic acid cycle. A metabolically important derivative of M.a. is malo-nyl-CoA, an intermediate of Fatty acid biosynthesis (see). 

Quinoxaune Derivatives Which Can Be Oxidized to Pyrazine-2,3-dicarboxyl,ic Acids on a Preparative Scaue... 

The separation of gas mixtures by polymeric membranes has become a commercially important methodology for a number of different systems (1). Several recent review articles have discussed the interaction between polymer structure and gas permeability properties (2,3). The quantification of the effect of polymer structure on gas transport properties recently has been reported (4,5) and it is now possible to optimize gas transport properties for well defined polymeric materials. For those materials which do not have a well defined data base it is necessary to prepare and measure the gas transport properties. The polyamide-imides (PAI) are a class of polymeric materials which do not have an extensive data base for gas transport properties (6,7). Work by Yamazaki and coworkers (8) demonstrated that PAI materials could be prepared easily and in a manner whereby the amide bond could be prepared from a phosphite activated carboxylic acid and an aromatic amine. Yang and CO workers (9-11) have shown that novel dicarboxyl ic acids could be prepared from trimellitic acid anhydride (TMA) and aromatic diamines and that these dicarboxylic acids could be coupled with a second diamine to form regiospecific PAI materials. Our focus was to examine the effects of a phenylene diamine and its alkylated analogs on the gas transport properties of regiospecific PAI materials and to identify those structures which maximized both permeability and selectivity. 

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