Methyl-2,3-dimethyl-2-butenoate

Lack of stereospecificity, extensive formation of olefinic products, and extensive tar formation limit the thermal decomposition of pyrazolines as a route to cyclopropanes.182 263 Light-induced decomposition of stereoisomeric pyrazolines establishes a method for the formation of cyclopropanes stereospecifically.222 Photolysis of 3-carbomethoxy-cis-3,4-dimethyl-l-pyrazoline (CCLI) produced cis-l,2-dimethylcycIopropane-l-carboxylate (CCLII) and without olefinic formation. Furthermore, irradiation of 3-carbomethoxy-trans-3,4-dimethyl-l-pyrazoline (CCLIII) gave [Pg.123]

When 2,2-dimethylpropanal is used to prepare the azomethine moiety, the corresponding azaallyl anion may be obtained when l,8-diazabicyclo[5.4.0]undec-7-ene/lithium bromide is used as base. The subsequent addition to various enones or methyl ( )-2-butenoate proceeds with anti selectivity, presumably via a chelated enolate. However, no reaction occurs when triethylamine is used as the base, whereas lithium diisopropylamide as the base leads to the formation of a cycloadduct, e.g., dimethyl 5-isopropyl-3-methyl-2,4-pyrrolidinedicarboxylate using methyl ( )-2-butenoate as the enone84 89,384. 

This methodology has been used in the synthesis of aspidosperma alkaloids220,221, the construction of an ABC ring precursor for steroids 222 and the preparation of an optically active phenanthronc in 93% ee 223. / -Substituted Michael acceptors such as methyl ( )-2-butenoate are generally unreactive with A-cycloalkylidene-l-phenylethanamines, however ( )-2-butenoyl cyanide is a useful alternative. This is shown in the synthesis of enantiomerically pure cis-dimethyl substituted bicyclic lactams224. 

Methyl-2-butenoic (P,P-dimethyl acrylic) acid, physical properties, 5 35t... 

Dihydro-2,2-dimethyl-7 -(((methylamino)carbonyl)oxy) -3-benzofuranyl (2j-2-methyl-2-butenoic acid, see Carbofuran... 

Cobalt is the catalyst of choice for the hydrocarboxylation of butadiene to adipic esters.89 The reaction is carried out in two steps, the first of which yields methyl-3-butenoate. This product can either be isolated or carried on to dimethyl adipate at high temperatures (Scheme 11). The first hydrocarboxylation occurs by the metal carboxylate insertion mechanism (vide supra). 

Before the modem era of organotransition metal reactivity, it was observed that nickel carbonyl reacted with 2-methallyl chloride in methanol to give methyl 3-methyl-3-butenoate and 2,5-dimethyl-1,5-hexadiene as a by-product. In THF at 25 °C, the diene was the exclusive product. This mild formation of a carbon carbon bond, and the interest in the synthesis of terpene-based natural products led to efforts to test the scope and limitations of the process. An obvious pathway involves stepwise oxidative addition of each aUyl unit followed by Reductive Elimination. As discussed below, the key intermediates (left vague in Scheme 48) are likely to involve Ni -Ni couples. 

Addition of (S)-l-phenylethylhydroxylamine to methyl ( )-2-butenoate gives a 93% yield of a 71 29 diastereomeric mixture, the major isomer of which is isolated in pure form by chromatography and subsequently transformed to (+)-(S)-3-aminobutanoic acid by cycliza-tion and hydrogenolysis12. Similarly, (Sj-l-phenylethylhydroxylamine is added to dimethyl (Z)-butenedioate to afford a 62 38 diastereomeric mixture in 84% yield which is further converted into the z-methyl ester of (S)-aspartic acid (28% ee)12. 

C7H1202 ethyl trans 2-methyl-2-butenoate 5837-78-5 429.15 37.121 1,2 11563 C7H1205 dimethyl 3-hydroxyglutarate 7250-55-7 526.48 46.434 2... 

C8H11N02 ethyl 2-cyano-3-methyl-2-butenoate 759-58-0 514.95 45.322 2 14328 C8H120 2,3-dimethyl-2-cyclohexen-1 -one 1122-20-9 455.43 39.619 2... 

The allylalkohol 6 turns out to be the obvious precursor of the protected diol 5, and 6 reasonably arises from a Shapiro coupling of cyclohexadienyllithium 7 with the cyclohexene-4-aldehyde 8 which is the product of oxidation and subsequent diol protection of the bicyclic hydroxylactone 9 the latter emerges from rearrangement of the Diels-Alder cycloadduct 13 of 3-hydroxy-2-pyrone 14 as the diene and 4-hydroxy-2-methyl-2-butenoate 15 as the electron-deficient dienophile. The cyclohexadienyllithium 7 originates from the sulfonylhydrazone of the ketone 10 which is, once again, a Diels-Alder cycloadduct of the protected 3-hydroxymethyl-2,4-dimethyl-l,3-pentadiene 12 and ketene 11 as the dienophile. 

In order to prepare the cyclohexenaldehyde 8, 3-hydroxy-2-pyrone 14 and ethyl 4-hydroxy-2-methyl-2-butenoate 15 are subjected to a Diels-Alder reaction in the presence of phenylboronic acid which arranges both reactants to the mixed boro-nate ester 19 as a template to enable a more efficient intramolecular Diels-Alder reaction with optimal control of the regiochemical course of the reaction. Refluxing in benzene affords the tricyclic boronate 20 as primary product. This liberates the intermediate cycloadduct 21 upon transesterification with 2,2-dimethylpropane-l,3-diol which, on its part, relaxes to the lactone 22. Excessive i-butyldimethyl-silyltriflate (TBSTf) in dichloromethane with 2,6-lutidine and 4-7V,A-dimethyl-aminopyridine (DMAP) as acylation catalysts protects both OH goups so that the primary alcohol 23 is obtained by subsequent reduction with lithiumaluminum-hydride in ether. 

Synonyms Benzyl trans-2,3-dimethyl acrylate Benzyl trans-2-methyl-2-butenoate Benzyl 2-methylcrotonate Benzyl trans-2-methyl... 

Citronellyl 3-methylcrotonate CAS 20770-40-5 EINECS/ELINCS 244-019-4 Synonyms Citronellyl senecioate 3,7-Dimethyl-6-octenyl trans-3-methyl-2-butenoate Properties Flash pt. (CC) > 130 C Toxicology TSCA listed Uses Fragrance in cosmetics Manuf./Distrib. Grau Aromatics http //www.grau-aromatics.de Citronellyl nitrile... 

Dimethyl-6-octenyl trans-3-methyl-2-butenoate. See Citronellyl 3-methylcrotonate... 

Synonyms 2-Butenoic acid, 2-methyl-, ethyl ester, (E)- Crotonic acid, 2-methyl-, ethyl ester, (E)- Ethyl trans-2,3-dimethyl acrylate Ethyl 2-methyl-2-butenate Ethyl (E)-2-methyl-2-butenoate... 

CAS 7785-33-3 EINECS/ELINCS 232-078-9 Synonyms 2-Butenoic acid, 2-methyl-, 3,7-dimethyl-2,6-octadienyl ester (E,E)- cis-a,p-Dimethyl acrylic acid, geraniol ester trans-3,7-Dimethyl-2,6-octadien-1-yl cis-a,p-dimethyl acrylate Geranyl trans-2-methyl-2-butenoate Tiglic acid, geraniol ester Empirical C15H24O2... 

Carbon is alkylated ia the form of enolates or as carbanions. The enolates are ambident ia activity and can react at an oxygen or a carbon. For example, refluxing equimolar amounts of dimethyl sulfate and ethyl acetoacetate with potassium carbonate gives a 36% yield of the 0-methylation product, ie, ethyl 3-methoxy-2-butenoate, and 30% of the C-methylation product, ie, ethyl 2-methyl-3-oxobutanoate (26). Generally, only one alkyl group of the sulfate reacts with beta-diketones, beta-ketoesters, or malonates (27). Factors affecting the 0 C alkylation ratio have been extensively studied (28). Reaction ia the presence of soHd Al O results mosdy ia C-alkylation of ethyl acetoacetate (29). 

A mixture of 9.5 g pyrrolyl-2-aldehyde, 29.2 g dimethyl-succinate and NaH (9.6 g of 50% suspension in oil) in 100 ml benzene is stirred at room temperature 6 hours, cooled and carefully acidified with glacial acetic acid. Add water and ether and dry, evaporate in vacuum or work up (JACS 72,501 (1950), JCS 1025(1959)) to get ca. 17 g (80%) 3-methoxycarbonyl-4-(2 -pyrrolyl)-3-butenoic acid (I) (recrystallize-acetone-benzene). A mixture of 12 g (I), 7 g sodium acetate and 70 ml acetic anhydride is left overnight at room temperature with occasional shaking. Then gradually raise the temperature to 70-75° over 2 hours, maintain for 4 hours and work up (see JCS 1714(1955), 986( 1958)) to get ca. 8 g (60%) methyl-4-acetoxy-indole-6-carboxylate (II) (recrystallize-petroleum ether). If desired, this can be converted to 4-OH-indole-6-COOH and 4-methoxyindole-COOH as described in the ref. or decarboxylated as described elsewhere here. If the 1-methyl cpd. is used, 1-Me-indole results. 

The reaction of 3-methyl-2-oxo-3-butenoates and dimethyl (amino-thiocarbonyl)malonate afforded (dihydro-1,3-thiazin-2-ylidene)malonate (1684) under acidic conditions, while in the presence of triethylamine, (tetrahydro-l,3-thiazin-2-ylidene)malonates (1685) were the products (88SC1043). 

SYNS APAVINPHOS a-2-CARBOMETHOXY-l-xMETHYLVINYL DIMETHYL PHOSPHATE 2-CARBOMETHOXY-1-PROPEN-2-YL DIMETHYL PHOSPHATE CMDP COMPOUND 2046 3-((DIMETHOXYPHOSPHINYL)OXY)-2-BUTENOIC ACID METHYL ESTER 0,0-DIMETHYL-0-(2-CARB0-METHOXY-l-METHYLVlNYL) PHOSPHATE DIMETHYL-1 -CARBOMETHOXY-1-PROPEN-2-YL PHOSPHATE DIMETHYL ESTER PHOSPHORIC ACID ESTER with METHYL 3-HYDROXYCROTONATE 0,0-DIMETHYL-0-2-METHOXYCARBONYL-1-METHYL-VINYL-PHOSPHAT (GERMAN) DIMETHYL 2-METHOXYCARBONYL-l-METHYLVINYL PHOSPHATE... 

Figure 5.2.10. Cellulose pyrolysate obtained at 59CP C by Py-GC/MS. The separation was done on a Carbowax type column. 1 CO2, 2 acetaldehyde, 3 acetone, 4 2-butanone, 5 2,3-butandione, 6 toluene, 7 water, 8 cyclopentanone, 9 methylfuran, 10 3-hydroxy-2-butanone, 11 hydroxypropanone, 12 cyclopent-1-en-2-one, 13 2-methylcyclopentenone, 14 acetic acid, 15 acetic acid anhydride, 16 furancarboxaldehyde, 17 methylcyclopentenone, 18 dimethylcyclopentenone, 19 5-methylfurancarboxaldehyde, 20 2,3-dihydro-2-furanone, 21 furan-2-methanol, 22 3-methylfuran-2-one, 23 2(5H)-furanone, 24 hydroxycyclopentenone, 25 3,5-dimethylcyclopentan-1,2-dione, 26 2-hydroxy-3-methyl-2-cyclopenten-1-one, 27 2-hydroxy-3-ethyl-2-cyclopenten-1-one, 28 2,3-dimethyl-2-cyclopenten-1-one, 29 phenol, 30 dimethylphenol, 31 3 thyl-2,4(3H,5H)-furandione, 32 3-butenoic acid, 33 1,4 3,6-dianhydro-a-D-glucopyranose, 34 5-(hydroxymethyl)-furfural.

METHOXYCARBONYL-1-METHYLVINYL DIMETHYL PHOSPHATE 2-BUTENOIC ACID. 3-((DIMETHOXYPHOSPHINYL)OXY)-,METHYL ESTER (SCI) 2-CARBOMETHOXY-1-METHYLVINYL DIMETHYL PHOSPHATE... 

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