Chloropyruvic acid

Caution The preparation op chloropyruvic acid should be carried out in a fume hood, as should the purification of 3-hydroxycincho-ninic acid and its decarboxylation. 

A. Chloropyruvic acid. In a 1-1. four-necked flask (Note 1) fitted with a sealed mechanical stirrer, dropping funnel, thermometer, and reflux condenser protected with a calcium chloride tube is placed 249 g. (2.83 moles) of pyruvic acid (Note 2). The stirrer is started and 394 g. (2.92 moles) of sulfuryl chloride (Note 3) is added dropwise over a period of 2 hours. During the addition the temperature is maintained at 25-30° by cooling with a water bath. 

The yield of light-yellow chloropyruvic acid is 333-340 g. (96-98%) (Note 6). 

The chloropyruvic acid prepared in this manner is satisfactory for use in the next reaction without purification. It often crystallizes to form a waxy solid or semisolid which is quite hygroscopic. I hc pure anhydrous material is rei)orted to melt at 45°, while the inonohydrate obtained l)y other melhods melts at 57 58°. The chloropyruvic acid is normally uscci immediately,... 

If the chloropyruvic acid remains essentially as a viscous liquid, it may be introduced via a dropping funnel containing a large-bore stopcock. If the material has set up to a waxy solid, it must be introduced in portions through a powder funnel. 

The method of synthesis described for chloropyruvic acid is essentially that reported. This procedure affords the product in excellent yields from readily available materials by a short, convenient route. Other less acceptable methods involve chlorination of pyruvic acid with sulfur dichloride or hypochlorous acid and the treatment of ethyl chloro(l-hydroxyheptyl)- or (o -hydroxybenzyl)oxalacetate 7-lactone with 50% hydrochloric acid. ... 

The procedure described for the preparation of 3-hydroxycin-choninic acid is adapted from that reported. This synthesis is successful when bromopyruvic acid or its ethyl ester is substituted for chloropyruvic acid. The reaction of isatin with chloropyruvic acid to produce 3-hydroxycinchoninic acid has been reported however, no details or physical properties were given. This method offers a decided advantage over the method involving diazotization of the difficultly accessible 3-aminocinchoninic acid. ... 

Sulfuryl chloride, reaction with pyruvic acid to yield chloropyruvic acid, 40,54... 

Isatin, reaction with chloropyruvic acid tb yield 3-hydroxydnchoninic acid, 40, 55... 

This procedure describes an efficient method for the synthesis of >99% enantiomerically pure ethyl glycidate from L-serine. Although preparation of potassium glycidate via cyclization of 3-bromo-2-hydroxypropionic acid,2 and from 3-chloro-2-hydroxypropionic acid (obtained by microbial reduction of chloropyruvic acid)3 was previously reported, the corresponding ethyl ester was never described. An enantioselective synthesis of the 2,3-epoxy acid by oxidation of 2,3-epoxypropanol has also been reported.4... 

We studied the P-elimination and replacement reactions using our pyridoxamine analogs [43]. Initially, we examined the relative rates for the P-elimination reactions between chloropyruvic acid and small pyridoxamine analogs carrying a basic side chain (Table 2.2). In the dimethylamino series the HC1 elimination rates were fastest with the shorter chain of 4, as expected for a process that requires only proton removal from the pyridoxamine 4 -CH2 group. The contrast with the data for transamination... 

Table 2.2 Relative rates for ( -elimination reactions between small pyridoxamine analogs and chloropyruvic acid.

Similar procedures are used to convert pyruvic acid into chloropyruvic acid (98% yield)" and ethyl uceluiiuetate into ethyl ehloroacetoucetute. ... 

Deduce structures for the quinolines produced from the following combinations (i) C16H11NO2 from isatin/NaOH then acetophenone (ii) C10H7NO3 from isatin/KOH then 3-chloropyruvic acid ... 

Chlorobenzaldehyde from aluminum chloride catalyzed chlorination of benzaldehyde, 10 Chloropyruvic acid,... 

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