2-Chloropropionate groups

Cyclopropanone equivalent. Unlike cyclopropanone, which is difficult to isolate, 1 is stable, easily obtained from 3-chloropropionic acid (Aldrich), and is a useful substitute for the ketone. Thus reaction of the silyl ether 2 with RMgBr provides adducts in which the OH group of 1 is replaced by R. The carbinol 1 is also a useful precursor to pyrroles, pyrrolines, and pyrrolizidines (equation I). 

Some preliminary studies were conducted to determine whether one of two proposed reactions could account for the appearance of pyruvate from dalapon. The precursor of pyruvate in this system is probably the a-hydroxy-a-chloropropionate. This compound is unstable and will spontaneously give rise to pyruvic acid. The enzyme apparently forms a-chloro-a-hydroxypropionate from dalapon. One reaction system by which the enzyme could form a-chloro-a-hydroxypropionate from dalapon would involve a direct substitution reaction (Reaction 1). In this case there would be a direct nucleophilic attack at carbon-2, led by a hydroxyl group to form the desired product. 

As chlorine substitutes for hydrogen in the methyl group of the acetate anion, the carboxylate basicity decreases (i.e., pKa decreases). The thermodynamic data for the Eu(III) and Am(III) complexes and the ligand pKa values are listed in Table II. Data for 3-chloropropionate (16) are also included. 

The pioneering paper on using molecular dynamics simulations to understand chiral gas chromatographic results was done by Konig s group [67]. Experimentally they found the S enantiomer of methyl-2-chloropropionate to be more retained on Lipodex D ([heptakis(3-0-acetyl-2,6-di-0-pentyl)-p-CD] coated on a capillary column) at 333 K. A large separation factor, a = 2.02, corresponding to a AAG = 2 kJ/mol i was observed and an attempt to discern the structural features of the transient complexes was made. 

Using the fact that the trans isomer was chiral, a derivative was synthesized where the bridging carboxylate group was the optically pure (i )-2-chloropropionate ((270) X = CHMeQCOO, n = Synthesized from the /X-CI2 species by reaction with the sodium salt of the acid, a... 

Another important plant protection agent based on 2,4-dichlorophenol is di-clofop-methyl, which is produced via the intermediate nitrofen (from 2,4-dichloro-phenol and p-nitrochlorobenzene) by reduction of the nitro group, diazotization, and hydrolysis of the diazonium salt to yield the phenol with subsequent reaction with 2-chloropropionic acid methyl ester. 

Reactions of Both Functional Groups. Hydrolysis of acrylonitrile catalyzed by hydrochloric acid yields 3-chloropropionic acid. Alcoholysis and chlorination occur simultaneously in the presence of sulfuric acid. Similarly, alcoholysis and hydrochlorination also occur. Addition of both ammonia and hydrogen produces both trimethylenediamine and propylamine. Treatment of acrylonitrile... 

Mitsui Toatsu investigated the rhodium-catalyzed version of this reaction, which can be conducted at a much lower syngas pressure (Scheme 4.22) [10]. To avoid deterioration of the catalyst by HCl, a buffer or an amine was added. 2-Chloropropionaldehyde, which is preferentially obtained, might be converted into racemic lactic acid by oxidation of the aldehyde group and replacement of the chloro substituent by a hydroxy group in a basic medium [11]. Alternatively, treatment of 2-chloropropionic acid with aqueous ammonia produces racemic alanine. 

Our initial experiments utilized 2 -deoxyadenosine in attempting to acquire knowledge of the reactivity of the 3 -hydroxyl group for condensation reactions with the p-nitrophenyl ester of 3-chloropropionic acid with free imidazole as catalyst. The choice of the 3-chloropropionic acid rested upon the feasibility of converting the halide first into an azide, then an amine, and finally a diazo derivative. 

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