A-Iodopropionic acid

NAD binding at pH 7.4 (156) and positive cooperativity at pH 8.5 (155), in agreement with earlier studies (101). Eisele and Wallenfels (119) have also provided support for the concerted model with studies on the rate of stereoselective inhibition of the yeast enzyme by the antipodes of a-iodopropionic acid and a-iodopropionamide at varying NAD concentrations. In similar experiments the muscle enzyme showed negative cooperativity. 

Alkoxy- or 2-aryloxy-5,6-dihydro-TAs 106 may be obtained in two ways—from 3-iodopropionic acid (1891CB3848) and from acryloyl halides (89USP4839356—by the action of a thiocarbamate (Scheme 35). 

Mr. Wislicenus has, in fact, recently announced that he has found an active acid in meat. This acid does not have, as has been believed, the constitution of the ethylene lactic acid but it is according to this author a physical isomer of the ordinary lactic acid. Indeed one cannot see that the ethylene lactic acid can be active, for the carbons of the radical are each one combined with two atoms of hydrogen, as the formula shows CH2 OH CH2 GOOH. We see also that the propylene glycol and the iodopropionic acid which are derived from the active lactic acid will preserve the rotatory power, but it will not be the same with the glycerine which one can derive from it, for in that case the central carbon atom is united with the two equal radicals CH2 OH,... 

The combination of aluminum Lewis acids and chiral diols has allowed for modest enantioselectivities in similar reactions using oxazolidinone templates and a-iodopropionate substrate as in Eq. (13.30) [42]. The 4,4-dimethyl substituent on the oxazolidinone (99) favors the s-cis conformation for the intermediate radical. Enantioselectivities of 32 and 34% and yields above 90% were obtained for ally-lations with R=H and R=Me respectively. 

Amido-propionic acids — Alanins — CiHiNOi — 89.— Two are known, isomeric with sarcosin and with lactamid. One, a Alanin,. CH,-CH (NH,)-COOH, is formed by the reduction of a nitroso-propionic acid by Sn-j-HCl. The other, j3 Alanin, CHiNHi—CH> —COOH, whose constitution is similar to that of glycocol, is formed either by the reduction of /J nitrosopropionic acid, or by the action of 13 iodopropionic acid on ammonia. either exists, so far as known at present, in nature. 

Hexakis(2,6-di-0-methyl)-a-CyD complexes with a small guest molecule, such as iodine and 1-propanol, crystallize with the cage-type packing structure [185]. Compared with the structure of the corresponding -CyD complex, the guest molecules in the both complexes are shifted to the secondary hydroxyl side from the center of the cavity. 3-Iodopropionic acid [186], m-nitroaniline [187], and acetonitrile [188] are also fully accommodated in the host cage . A 3-0 acetylated host, hexakis(2,6-di-0-methyl-3-0-acetyl)-a-CyD, was crystallized from butylacetate [189]. In spite of the disruption of intramolecular hydrogen bonds, the host molecule is in a round shape because of the inclusion of butylacetate. 

F. Beilstein/ by the action of silver oxide on j8-iodopropionic acid obtained what he called hydracrylic acid, since it decomposed on heating into water and acrylic acid, and he formulated it C12H22O11. Its correct formula was found by W. Moldenhauer.2 Heintz believed that it was the same as Wislicenus s ethylene lactic acid, giving a zinc-calcium double salt, but Wislicenus thought they were different. The position was first clarified by Erlenmeyer, who showed that Wislicenus s ethylene lactic acid is hydracrylic acid. Wisli-cenus had found that paralactic acid is optically active (dextro-rotatory), whilst ordinary fermentation lactic acid is inactive, and he supposed that they should be represented by the same formula, CH3 CH(0H)-C02H. He says (1869) Thus is given the first certainly proved case in which the number of isomers exceeds the number of possible structures. Facts like these compel us to explain diflFerent isomeric molecules with the same structural formula by different positions of their atoms in space, and to seek for definite representations of these. ... 

Wislicenus introduced the use of molecular silver in the synthesis of adipic acid from iodopropionic acid, synthesised hydantoin from cyanic acid and glycocoll, glutaric acid (with L. Limpach), and methyl j8-butyl ketone from methylethylacetoacetic ester. He prepared cyclic ketones of dibasic acids by heating the calcium salts, and discovered vinyl ether and vinylacetic acid. The earlier history of acetoacetic ester has been dealt with (see p. 528) two theories of its structure were proposed that of Frankland and Duppa (1865), who represented it as CH3 CO CH2-COOC2H5, and that of Geuther, who discovered the compound (1863), and represented it at first by a type formula (C = 12, O=8) ... 

Polyurethane sheets were stirred with a solution of 0.1 M sodium isopropylate in iso-propanol at 4°C. Two hundred mg of 3-iodopropionic acid were added and stirred for 2.5 h. Samples were rinsed with deionised water, 0.1 M HCl and again with deionised water. 

A new synthesis of ( )-menthofuran (155) has been described which involves a three-step reaction sequence from the cyclohexanone (152) via direct C-alkylation with ethyl 2-iodopropionate to give (153) (Scheme 35). Hydrolysis of the diester (153) with hydrochloric acid afforded 3,6-dimethyl-2,4,5,6,7,7a-hexahydrobenzofuran-2-one (154). The final step in the sequence was the conversion of the a,/3-unsaturated y-lactone ring into the furan ring by reduction with lithium aluminum hydride and 2-propanol to afford (i)-menthofuran (155) in satisfactory yield (80JOC1517). 

Sodium fi-iodopropionate according to the last-named investigators, yields a little iodoform besides iodine the gases formed are principally carbonic acid. Carbon monoxide and oxygen occur only in small quantity. 

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