Iso crotonic acid

I so-Crotonicacidozonide (Isocroton saure-o zonid in Ger). C4H606, clear syrup, decompd by w or on standing extremely expl. Was prepd by the action of ozone on a chloroformic soln of iso-crotonic acid, CH3.CH CH.COOH Note Crotonic acidozonide was prepd by Briner and Franck (Ref 3)... 

Crotonic and Iso-crotonic Acids.—We have then for the two cro-tonic acids only one possible constitution remaining and their synthesis proves that both of these acids do in fact have the same structural constitution, viz., that of /3-methyl acrylic acid or A2-butenoic acid. 

Now iso-crotonic acid is readily transformed into crotonic acid by simply heating to 170° and.crotonic acid may likewise be converted into iso-crotonic acid. Also each of them by the addition of hydrogen iodide is converted into the same saturated compound, viz., /3-iodo butyric acid. 

Geometric Isomerism.—The theory was applied by vanT Hoff and Wislicenus to the present case of the isomeric crotonic acids, and other compounds of similar character, viz., maleic acid and fumaric acid (p. 290). If two carbon atoms, instead of being linked by one bond, become directly linked by a double bond, as in the case of crotonic acid and iso-crotonic acid, the relation of the two carbon atoms, and of the two groups containing them, becomes fixed in space, because the double... 

Crotonic and Iso-crotonic acids or /3-Methyl acrylic acid... 

Crotonic acid, the solid, crystallizes from hot water in fine needles which melt at 71° to 72° and boil at 180° to 185°. It is soluble in 12 parts of water at 15°. Iso-crotonic acid, the liquid, is a colorless oily liquid with a strong odor resembling butyric acid. It boils at 172° and melts at about 15°. It mixes with water in all proportions. 

Two pairs of higher acids of this series are known, the members of each pair being related to each other as are crotonic and iso-crotonic acids. The first two are known as tiglic acid and angelic acid and they have been proven to be the alpha-methyl substitution products of the two crotonic acids. Tiglic acid is a-methyl crotonic acid and is therefore the cis form. Angelic acid is a-methyl iso-crotonic acid and is the trans form. 

Isomerism.—Cinnamic acid occurs as geometric stereo-isomers, as cis and trans forms like maleic and fumaric acids (p. 291) and crotonic and iso-crotonic acids (p. 177). This is apparent as it is... 

The transition from -aminobutyric-acid (GABA) to trans-4-amino-crotonic acid, followed by cyclization into iso-guvacine, and finally into THIP (Figure 16.13), achieves simultaneously the rigidification of the flexible GABA molecule and the production of THIP, a metabolically stable and still potent GABA agonist. ... 

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