Imidazole propionic acid

This assumption of Pauly s was confirmed by Knoop and Windaus, who found that histidine is resistant to reduction by sodium and alcohol whereas the pyrimidine rii is very unstable towards this reagent. On reducing Frankel s oxydesaminohistidine, which is obtained from histidine by the action of nitrous acid, they obtained /8-imidazole-propionic acid. This compound was identical with the synthetical product prepared from glyoxylpropionic acid, ammonia and formaldehyde — ... 

Windaus and Vogt in 1908 showed that FrSnkel s chlorohistidine carboxylic acid was the hydrochloride of /3-imidazole-propionic acid. 

Urocanic acid (imidazole acrylic acid) is converted to the imidazole propionic acid in the presence of uro-canase by oxidation of the ring carbon and reduction of the side chain (see Fig. 3-23). Urocanase has been found in the liver of mammals its acivity varies considerably, depending upon the species. Urocanase has been purified extensively from beef liver [95]. The pro-... 

In a recent study, Fernandez-Bertran et al. used mechanochemical reactions to prepare a number of hemin complexes with amino acids such as arginine, histidine, lysine, methionine and tryptophan. The basic amino acids react with the hemin peripheral propionic acid groups, while arginine is also able to form a pentacoordinated complex at the Fe(III) centre. The reactions were followed by IR and Mossbauer spectroscopies [77a]. The solid-state reaction of hemin with KCN, Na2S and various substituted imidazoles has also been investigated [77b]. 

N1 - IMIDAZOLE-4-PROPIONIC ACID, alpha-AMINO-alpha-(FLUOROMETHYL)-... 

The fact that the pKi value is increased by the COO- anion in the polymer is supported by MO calculations (CNDO/2) (79). The closer distance between COO-and the counter cation gives the lower superdelocalizability value of N(3) in imidazole, in the case of 0-(5-imidazolyl)-propionic acid. Also, the closer distance between COO and imidazole gives the higher superdelocalizability value of N(3) in the imidazole, being adopted as a model case of 4-methylimidazole and the acetate anion system. Results are shown in Fig. 7. 

A mixture of 21.6 g. (0.20 mole) of o-phenylenediamine, 22.2 g. (0.30 mole) of propionic acid, and 20 ml. of 4 A hydrochloric acid is refluxed for 30-40 minutes. The mixture is filtered, and the filtrate is neutralized with aqueous ammonia. The precipitated 2-ethylbenz-imidazole is removed by filtration and recrystallized from a 1 1 mixture of ethanol and water to give a 70% yield of product melting at 177°. 

A significant increase in the measured COj concentration was observed after the addition of 10 mmol/1 of a-keto-isovaleric acid (148% increase from baseline), a-keto-isocaproic acid (120%), phenylacetic acid (100%), DL-a-keto-P-methyl-A-valeric acid (100%), homogentisinic acid (50%), P-phenylpyruvic acid (45%), hydroxyphenyl acetic acid (32%), propionic acid (25%), ace-toacetic acid (25%), hydroxyphenyl pyruvate acid (23%), and 20 mmol/1 of hydroxyphenyl lactid acid (65%) or salicylic acid (76%). A significant decrease was observed after the addition of 20 mmol/1 of ascorbic acid (33%), DL- -hydroxybutyric acid (25%) or imidazole lactic acid (25%). No effect after the addition of 10 mmol/1 of imidazole-4-acetic acid, methylmalonic acid, 5-hy-droxyindole acetic acid or 20 mmol/1 arginosuccinic acid, Z.-(+)-hydroxybu-tyric acid (E525). 

A Kolbe cross-coupling electrolysis reaction of 170 with propionic acid (MeOH, Et N, 35 °C) furnishes methyl (iS)-2-hydroxypentanoate which, after protection (TBS-Cl, imidazole, DMF) and saponification (KOH, EtOH), gives the TBS-protected a-hydroxy acid 171 in 58% overall yield [60].This hydroxy acid supplies the 0-1 to C-3 fragment in the convergent synthesis of the antibiotic myxovirescine (172). 

Free poiphyrin motions could be considerably altered in the presence of a metal ion, such as the iron, which covalently links the porphyrin to the protein. Linkages between heme and protein involve iron and the porphyrin part of the heme. Iron is linked to an imidazole group of the proximal histidine, His-93. The other heme protein bonds involve, on the heme side, the propionic acid groups, the vinyl groups and the porphyrin as a whole. The two heme propionates help to stabilize the heme by making hydrogen bonds to the side chains of the distal histidine (His-64) and an arginine. 

An early example of this approach was that of Lautsch et al. who coupled various histidine-containing tripeptides to the propionic acid side-chains of mesoporphyrin IX la (Scheme 2). After metal insertion into the porphyrin, intramolecular coordination by the histidyl imidazole was possible depending on the length of the peptide chain. Similarly, histidine-containing peptides were attached to the ethyl side chains of mesoporphyrin IX via sulfide linkages to give 2(b-d), a situation similar to that in cytochrome c. Losse and Miiller coupled L-histidine methylester and protohemin 3 with dicyclohexylcar-... 

Scheme 2 Synthesis of the linear dyad 1. (a) Imidazole ropionic acid (10 1, v/v), 140°C, 4 h (26%) (b) Pd(PPh3)4], K2CO3/H2O, toluene, 80°C, 16 h (c) propionic acid, 150°C, 16 h (d) Pd(PPh3)4], K2CO3/H2O, toluene, 80°C, 16 h, 72% (e) 4-bromo-aniline, propionic acid, 150°C, 16 h, 88% (/) [PdCl2(dppf)] CH2CI2, bis(pinacolato)diboron, 1,4-dioxane, KOAc, 70°C, 16 h, 78% (g) [Pd(PPh3>4], K2CO3/H2O, toluene, 80°C, 16 h, 40% (h) ethanolamine, K2CO3, 160°C, 0.5 h, 20%. Route A one-pot imidization. Route B base-promoted coupling reaction between napthalene monoimide derivatives...

Several methods have been reported for the monofunctionaUzation of PDI [6] including one-pot imidization (route A) or a base-promoted coupling reaction between naphthalene monoimide derivatives (route B) [7], as shown in Scheme 2. We found the one-pot imidizatitMi reaction (route A) to be more practical than route B route B consisted of five steps and the open-form product 6b was labile under the basic reaction conditions required to produce the closed product 6a. The one-pot imidization, route A, was simple and 3 could easily be recovered via column chromatography because the use of an excess amount of 3 was necessary. Concerning the solubility and reactivity of perylene tetracarboxylic acid dianhydride (PDA) 4, the imidization of 4 was, first, carried out with 2,6-ditsopropylaniline (5) in imidazole then 3 in propionic acid solution was added to produce the closed product PDI 6a. 

Histamine possesses hormone activity in animals (E 3.1) and acts as a neurotransmitter (E 3.2). It is a plant feeding deterrent present, for instance, in nettle toxin (E 5.5.3). Also the alkaloid pilocarpine has strong physiological activity in vertebrates and deters potential predators (E 5.5.3). It is used as a cholinergic drug in medicine (F 2). Urocanic acid, hydantoin propionic acid, imidazoleacetic acid riboside, 1-methylhistidine, 1-methylimidazoleacetic acid and other imidazole derivatives are involved in the removal of L-histidine and histamine residues from the organism of animals. They are found in the urine. Urocanic acid is also a constituent of sweat (E 1). It is involved in the protection of skin to UV radiation (E 2.2). 

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