3-Methylcrotonic acid

Alkynes are easily carboxylated by C02 and usually offer lactones or pyrones as products. However, in several cases carboxylic acids can also be obtained. For example, 2-butyne reacted with C02 in the presence of a [Ni(CDT)] (CDT = 1,5,9-cyclododecatriene) catalyst and /V,/V,/V, /V -tetramethyl-l,2-diamine (TMEDA) as base to yield 2-methylcrotonic acid.21 Similarly, the reaction of terminal alkynes was catalyzed by Ni(COD) in a highly regio- and chemoselective manner in the presence of DBU as base affording E-acrylic acids in >85% yield (Scheme 6.13).84... 

E.27) (E.27) 2-Butenoic acid, 2-methyl, ( )-, (E)-2-methylbut-2-enoic acid, tiglic acid, r/wrv-tiglic acid, 2,3-dimethylacrylic acid, ( )-2-methylcrotonic acid 80-59-l] FEMA 3599 undefined stereochemistry... 

The reaction of alkynes with carbon dioxide in the presence of nickel (o) catalysts leads to the formation of metallacyclic 1 1 and 2 1 complexes. For example, the reaction of dimethylacetylene with carbon dioxide, in the presence of 1,5,9-cyclododecatrienenickel and Af,Af,A, Af-tetramethylenediamine, affords the five-membered ring metallacycle 20 in 65 % yield Hydrolysis of the metallacycle affords 2-methylcrotonic acid. 

A point of interest in connection with this reaction is that tiglic acid is the cis-isomer of 2-methylcrotonic acid, and it was the earlier belief that crotonase was specific for trons-enoyl acids. With highly purified crotonase it has been determined that both ds- and [Pg.108]

Figure 6 and 7. Surface grafting of polyethylene (PE) and polypropylene (PP) films with acrylic acid (AA), methacrylic acid (MAA), crotonic acid (CA), tiglic acid (TA), 3-methylcrotonic acid (3-MCA) and a-methyl cinnamic acid (a-MCA), measured by absorption of visible light after grafting for 2 min. with vapor phase method and dipping in aqueous solution of crystal violet. 

A photochemical approach to the synthesis of precocenes /, II, and III, interesting as juvenile hormome inhibitors [177,178], has been deviced starting from the phenolic esters of 3-methylcrotonic acid. This is shown in Scheme 61 for the synthesis of precocene I (235) [179] and in Scheme 62 for the synthesis of precocenes II (238) and III (239) [180]. The rate of the cyclization process leading to chromanones, like 234 or 237, has been found to depend on the stereochemistry of the double bond. Thus, ring closure is more rapid for the trans than for the cis isomer, although no clear-cut trend can be established [181],... 

The Ireland-Claisen rearrangement of a 2-fluoroallylic ester of 3-methylcrotonic acid followed by a tandem Cope rearrangement to prepare a 6-fluoroocta-2.6-dienoic acid,7 is given in Section 5.1.5.1. (see compound 11). 

In 1971, a child with biotin-responsive (J-methylcrotonylglycinuria was reported.This individual had metabolic ketoacidosis and elevated concentrations of urinary P-methylcrotonic acid and 5-methylcrotonylglycine. Several days after being given oral biotin, his symptoms resolved, and the urinary metabolites cleared. He subsequently was shown to have deficient activities of all three mitochondrial carboxylases in his peripheral blood leukocytes and skin fibroblasts. This was the first child to be diagnosed with what was called multiple carboxylase deficiency. 

Hydroxy-isovaleric acid (hydration products of 3-methylcrotonic acid) 3-Methylcrotonyl glycine... 

Methylcrotonic aciduria. TTiere is, among other things, excess excretion of beta-methylcrotonic acid, a substrate in the course of leucine breakdown. Possibly the defect may lie in the enzyme at this step. Administration of biotin, which normally functions at this step in leucine breakdown, may help improve the symptoms. 

Methylcrotonylglycinuria 3-Methylcrotonic acid, 3-methylcrotonyl-glycine, 3-hydroxypropionic, 2-methyl-citric, 3-hydroxy-3-methylbutanoic... 

Carboxylic Acids. Carboxylic acids have been esterified to wood catalyzed with trifluoroacetic anhydride (72, 73). Several unsaturated carboxylic acids react with wood by the trifluoroacetic anhydride impelling method to give an increase in oven-dry volume and ASE, and a decrease in wood crystallinity and moisture content (74). Reactions of wood with p-methylcrotonic acid (Reaction 1) give a degree of substitution high enough to make the esterified wood soluble in acetone and CHCI3 to the extent of 30% (75). 

Fujiwara, K., Takahashi, H., and Ohta, M., 4-Chloro-3-methylcrotonic acid derivatives and phosphonates, Bull. Chem. Soc. Jpn., 35, 1743, 1962. 

Binapacryl (29) is a compound with an action weaker than that of dinocap, and was initially also used as an acaricide. Its structural basis is dinoseb (28), which is an active substance with herbicidal properties. Binapacryl is formed by (he esterification of dinoseb with 3-methylcrotonic acid chloride, its chemical composition being 4,6-dinitro-2-jec-butylphenyl-3-methyl crotonate. 

Binapacryl. 3-Methyl-2-butenoic acid 2-(i-meth-ylpropyl)-4,6-dinitrophenyl ester 3-methylcrotonic acid 2-seC butyl-4,6-dinitrophenyi ester 2-sec-butyl-4,6-dinitro-phenyi 3,3-dimethylacrylate 2-sec-butyl-4,6-dinitrophenyl 3-methyl-2-butenoate 2 sec-butyl-4,6-dinilrophenyl 3-methylcrotonate 2 -see-butyl-4,6-dinitrophenyl senecioate 3,3-dimethylacrylic acid 2-sec-butyl-4,6-dinitrophenyl es. ter 4,6-dinitro-2-sec-butylphenyl P,P-dimethylacrylate 3-methyl-2-butenoic acid 2-sec-butyl-4,6-diniirophenyl ester dinoseb methacrylate senecioic aeid 2-sec-butyl-4,6-dinitrophenyl ester ENT 25793 HOE 2784 Acricid Am-box Endosan Morocide Niagara 9044. mol... 

Chloro-3-hydroxy-3-methylbutyric acid is obtained on addition of aqueous HOC1 to a suspension of 3-methylcrotonic acid (/ ,/ -dimethylacrylic acid).285... 

Methoxybromination can be effected directly by means of bromine. For example, when a current of air laden with bromine is passed with cooling through a methanolic solution of 3-methylcrotonic acid it affords 75% of 2-bromo-3-methoxy-3-methylbutyric acid 310 MgO is added to the reactants to remove hydrogen bromide, but alternatively311 AgN03 and CaC03 may be used. 

Thus the isomeric a-methylcrotonic acids are obtained from 2-butyne as illustrated in Schemes 2.60 and 2.61. 

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