Of tetrols

Isocrotonic acid can be prepared by the stereospecific cis-hydrogenation of tetrolic acid3 or, mixed with the acid with sodium amalgam.4 The eis-acid can also be prepared in small amounts by isomerization of the frana-acid.6 The method herein described is much less laborious than the older procedures.2... 

Relative Differences in the Amounts of Tetrols and a Major Unknown Metabolite Formed by Microsomes from Livers of Rats Fed Various Diets... 

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]... 

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. 

The reaction of hydroxide ion with carbocation 82 is expected to occur at the diffusion-controlled limit because proton transfer from the /i-OI I is thermodynamically favorable, and the activation barrier for collapse of the resulting zwitterion (108, Scheme 32) to reform the epoxide ring should be absent or very small. A concerted mechanism for this reaction is enforced if zwitterion 108 is too unstable to exist as an intermediate.104 The attack of hydroxide ion as a base on 82 as shown in Scheme 38 must be energetically more favorable than attack as a nucleophile to yield tetrol product. The exact yield of tetrol from direct combination of hydroxide ion with carbocation 82 could not be estimated, but is negligible or very small. 

Hydrolysis isolation of tetrol by Sep-Pak chromatography clean up by immunoaffinity chromatography (anti BP-tetrol-modified guanosine column)... 

It was of interest to extend the reactions of tetrols with cyclic diketones to produce a variety of spiro polymers with less oxygen in the base chain and with other functional groups present... 

It thus appears that a wide variety of tetrols and cyclic diketones can be used to prepare a large variety of soluble polyspiroketals. It appears that the reaction can be made to go readily when the ketal contains either five-, six-, seven-, or eight-membered rings. Some of the polymers containing the five-, seven- and eight membered rings can, of course, be considered to be a hybrid between ladder polymers and spiro polymers. An effort will be made to see what other cyclic ketals are useful for the formation of spiro polymers and what other types of reactions besides the ketal formation will produce similar polymers. 

The spectroscopic investigations [50, 51] give the fundament for propose, than the structure of macromolecules of PPSSO, obtained by condensation of tetrole T, and differs from structure of one, obtained from phenyltrlchlorosllane by anion polymerization at present of the Initiator of basis type. The conducted experimental Investigations allow suggest that the macromolecules with kun segment about 50 A have the structure near for cis-antl-c/5-tactic one [50] (Scheme 7) ... 

Figure 1 Supramolecular association in tetrolic acid with the carboxylic acid carrying no additional functional groups, (a) Dimer formation via the eight-membered -HOCO 2 homosynthon and (b) catemer formation in the crystal structure of a second form of tetrolic acid. The 0-H- -O hydrogen bonds are shown as orange dashed lines. In each of the motifs, the carboxylic acids are syn-syn. It is noted that for the catema- motif, anti-anti and, more rarely, alternating syn-anti carboxylic acids are known.

Figure 5 Molecular packing diagrams of (a) a and (b) p forms of tetrolic acid which are carboxylic acid dimer and catemer synthon polymorphs.

Parveen, S., Davey, R. J., Dent, G., and Pritchard, R. G. 2005. Linking solution chemistry to crystal nucleation The case of tetrolic acid. Chem. CommurL 12 1531. 

Bailey also extended this work to the preparation of the polythioketals using penaerythritol tetrathiol and cyclic diketones, and he reported the use of a number of tetrols with cyclohexanedione to give thermally stable, insoluble polyspiroketals, as described in Table VII. 

TABLE VII Preparation of Polyspiroketals by the Reaction of Tetrols with 1,4-Cyclohexanedione [69]... 

A variation on a literature procedure draws attention to a useful method for the synthesis of tetrolic acid. Copper dienolates derived from a,jS-unsatur-ated acids undergo y-alkylation with a regioselectivity of 91%. A full paper has appeared from Mulzer and his co workers on the control of 1,2-/1,4-regioselectivity in the additions of carboxylic acid dianions to a,jS-unsaturated carbonyl compounds. The addition of phenyl acetate dianion (23) (Scheme 20) to a,/3-un aturated aldehydes leads to the f/ireo-unsaturated /S-hydroxy-carboxylic acid (24) the threo and erythro ratio of 5 examples was >9 1. 

The crystal structures of a- and /5-forms of tetrolic acid, of anhydrous acetylenedicarboxylic acid, and but-3-ynoic acid have been determined. 

Scheme 10.19 Bridging of tetrol cavitand with pentaethyleneglycol ditosylate to form three different crowncavitand products...

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