Tetrolic acid

Thus sodio derivative of propyne can be converted into tetrolic acid as per following scheme ... 

Ethyl tetrolate Tetrolic acid, ethyl ester (8) 2-Butynoic acid, ethyl ester (9) (4341-76-8)... 

Patents state that the addition products from 2,2,6,6-tetramethyl-piperidin-4-ol and tetrolic acid are heat and light stabilizers for polymers.276-277... 

However, HBr addition to tetrolic acid and phenylpropiolic acid in benzene is reported to afford the opposite regioisomers (equation 122),170 and the stereochemistry of HBr addition to PhCWCCChEt171 and NCC CCN172 is unclear. 

Propionaldehyde Propanal Tetrolic acid 2-Butynoic acid... 

Gavezzotti, A., Flippini, G., Kroon, J., van Eijck, B. P. and Klewinghaus, P. (1997). The crystal polymorphism of tetrolic acid (CHsC CCOOH) a molecular dynamics study of precursors in solution, and in crystal structure generation. Chem. Fur. J., 3, 893-9. [183]... 

Cj Pfopiolic acid C< 2 Butynoic (tetrolic) acid Ethynylacetic acid Acetylenedicaiboxylic acid... 

To avoid spattering of the solid the desiccator is evacuated slowly. If drying is incomplete, an aqueous layer will be left in the hexane solution when the tetrolic acid is recrystallized. 

Prolonged boiling should be avoided since some tetrolic acid is lost by volatilization. 

The submitters obtained yields of tetrolic acid as high as 67.2 g. (80%). 

In one run the submitters passed excess methylacetylene (1.6 moles) into a solution of sodium in liquid ammonia until the color turned from blue to white. No ferric nitrate was used. This somewhat shorter procedure yielded pure white sodium methylacetylide and did not diminish the yield of tetrolic acid. Excess methylacetylene is necessary because 0.5 mole is converted to propylene. 

Tetrolic acid has been prepared by treatment of acetoacetic ester with phosphorus pentachloride followed by dehydrochlorination of the reaction products by the base-catalyzed isomerization of 3-butynoic acid and by the treatment of 4,4-dibromo-3-methyl-2-pyrazolin-5-one with alkali followed by acidification. ... 

Numerous examples of the preparation of versatile and valuable starting materials are also evident. Current theoretical interest in adamantane is reflected by a convenient procedure for its preparation (p. 8). 2-Cyclopentenone (p. 38) and 2-cyclopenten-1,4-dione (p. 36) are not only useful dienophiles for Diels Alder reactions but also attractive starting materials for a variety of compounds of theoretical interest. Similarly, the preparations of allene (p. 12), tetrolic acid (p. 97), ethylene sulfide (p. 59), and 2-norbornanone (p. 79) provide convenient access to exceptionally useful compounds. 

RC CNa and derived products. Tetrolic acid is prepared by conversion of propyne into the sodio derivative, carbonation, and acidification. For the preparation of 1-hexyne, Campbell and Campbell passed acetylene into 3 1. of liquid... 

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