Achilleic Acid

Equisetic Acid Citridic Acid Achilleic Acid 1-Propene-1,2,3-tricarboxylic Acid... 

Achilleaic acid Achilleic acid Aconitic acid AI3-14615 3-Carboxy-2-pentenedioic acid 3-Carboxy-glutaconic acid CCRIS 2507 Citridic acid Citridinic acid EINECS 207-877-0 Equisetic acid FEMA No. 2010 Glutaconic acid, 3-carboxy- HSDB 635 NSC 7616 Propene-1,2,3-tricarboxylic acid 1-Propene-1,2,3-trioarboxylic acid 1,2,3-Propenetricarboxylic acid 2-Pentenedioic acid, 3-carboxy- Pyrocitric acid. A plasticizer for buna rubber. Leaflets or plates dec 198, 204, 209, soluble in H2O (18.2 g/100 ml, 13 , 50 g/100 ml, 25 ), in 88 /o EtOH (50 g/100 mi), slightly soluble in EtzO. 

A way round these difficulties is to use an ether or an amide that has a built-in weakness so that the over-vigorous conditions are not needed. This Achilles heel for an ether is commonly the THP group that makes the ether into an acetal. Dihydropyran, DHP 26, is protonated on carbon 27 to give the cation 28 that captures the alcohol to give the mixed acetal 29, usually referred to as the THP derivative . After the reaction the hydrolysis needs only the weak aqueous acid used for acetals. The secret is that the weak acetal bond (b in 30) is cleaved4 rather than the strong ether bond (a in 30). 

Dissolve 500 mg collagen type I from bovine Achille s tendon into 200 ml of 0.5 mol/L acetic acid in water, pH 2.8... 

Cbz-protected amines behave like amides—they are no longer nucleophilic, because the nitrogen s lone pair is tied up in conjugation with the carbonyl group. They are resistant to both aqueous acid and aqueous base, but they have, to use the analogy we developed in the last chapter, an Achilles heel or safety catch—the benzyl ester. The same conditions that removed benzyl ethers in Chapter 24 will remove Cbz HBr or hydrogenolysis. cleavage of Cbz (Z) in HBr/AcOH... 

So, where is the safety catch The important point about Fmoc is that is has a rather acidic proton (p Ca about 25), shown in black. The proton is the Achilles heel treatment of Fmoc-protected amines with base eliminates a fulvene to reveal the NH2 group. 

Figure 38 5 Short term Fe uptake rates from model iron/ligand complexes hy Trichodesmium colonies collected in the suhtropical Atlantic Ocean. Shown are uptake rates from Fe complexed to a trihydroxamate siderophore (desferrioxamine), a dihydroxamate siderophore (rhodoturulic acid), and a porphyrin (protoporphyrin IX). For comparative purposes, uptake rates were also measured using added inorganic Fe (111). Achilles et al. (2003), Limnology and Oceanography 48 2250-2255.

A second collagen sample was bovine Achilles tendon collagen (Schwartz Mann, Inc.). This material resisted solvation in all simple aqueous solutions and even in strong acids, but it could be solubilized with time by dichloroacetic acid (DCA). Thus, films formed from this sample had to be cast from DCA. 

The clinical picture is characterized by xanthomas, particularly on the tendons (especially the Achilles tendon). Xanthomas consist of cholesterol and cholestanol. The enzyme defect also results in disturbed vitamin D metabolism. Osteoporosis is thus observed quite often, with a tendency towards spontaneous fractures. (208) Striking clinical features are cerebral functional disorders (from deviant behaviour to severe dementia, motor disturbances and convulsions) as well as peripheral neurological symptoms caused by cholestanol deposits. (211) High concentrations of apolipoprotein B and cholestanol are found in the CSF. (213) Treatment is based on the administration of chenodeoxycholic acid (750 mg/day). Effectiveness is improved if HMG-CoA reductase inhibitors (e. g. pravastatin) are used concomitantly. (207, 212)... 

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