3- Methyl-2-butenyl esters

SYNS BENZOIC ACID, 2-HYDROXY-, 3-METHYL-2-BUTENYL ESTER 2-BUTEN-l-OL, 3-METHYL-, SAUCYLATE 3-METHYL-2-BUTENYL SALICYLATE... 

BENZOIC ACID, 3-METHYL-2-BUTENYL ESTER see MHLT50... 

DeesterificationJ 3-Methyl-2-butenyl esters are cleaved by I2 at room temperature therefore, such esters may serve in selective protection of acids. Simple allyl esters are unreactive. 

Hexanoic acid, 3-methyl-2-butenyl ester. See Prenyl caproate... 

CAS 76649-23-5 EINECS/ELINCS 278-516-2 Synonyms Propanoic acid, 2-methyl-, 3-methyl-2-butenyl ester Vertenol isobutyrate... 

Studies on banana tissue slices have shown that valine and leucine concentrations increase about threefold following the climacteric rise in respiration [10]. Radioactive labeling studies have shown that valine and leucine are transformed into branched chain flavor compounds that are essential to banana flavor (2-methyl propyl esters and 3-methyl butyl esters, respectively). As can be seen in Figure 4.6, the initial step is deamination of the amino acid followed by decarboxylation. Various reductions and esterifications then lead to a number of volatiles that are significant to fruit flavor (acids, alcohols, and esters). Recent work has shown that amino acids play a role in apple flavor as well. For example, isoleucine is the precursor of 2-methyl butyl and 2-methyl butenyl esters in apples [24,25]. An unusual flavor compound, 2-isobutylthiazole, has been found to be important to the flavor of tomato. It is hypothesized that this compound is formed from the reaction of 3-methyl-l-butanal (from leucine) with cysteamine. 

Auf analoge Weise erhalt man aus z. B. 6-Acetoxy-l, 8-menthadien 6-Amino-1,8-menthadien (6-Amino-4-isopropenyl-l-methyl-cyclohexen 6-Amino-limonen) in 84%iger Ausbeute1. Bei einer Variante der letzteren Reaktion wird ein Phosphorsaure-(4-acetoxy-2-butenyl-ester) zunachst mit 2-Methyl-piperidin umgesetzt und dann in der obigen Weise weiter verfahren man erhalt auf diese Weise 4-Amino-I-(2-methyl-piperidino)-2-buten in 84% Ausbeute1 ... 

An interesting variation of the Dieckmann cyclization involves vinylogous activation of a methyl group in a 2-butenyl ester. Reaction of an a-halo ester with the enethiol formed by treatment of an acetoacetic ester, which may be substituted at the a-position, with hydrogen sulfide produces (92) in satisfactory yield. Treatment of these compounds with sodium in benzene produced the 4-hydroxythiophene-2-acetic acids (94) (40JCS1385). The product undoubtedly involved the intermediate (93), in which the activated methyl goup has condensed with the ethoxycarbonyl group in typical Claisen fashion. 

The carbopalladation is extended to homoallylic amines and sulfides[466. Treatment of 4-dimethylamino-l-butene (518) with diethyl malonate and Li2PdCl4 in THF at room temperature leads to the oily carbopalladated complex 519, hydrogenation of which affords diethyl 4-(dimethylamino) butylmalonate (520) in an overall yield of 91%. Similarly, isopropyl 3-butenyl sulfide (521) is carbopalladated with methyl cyclopentanonecarboxylate and Li2PdCl4. Reduction of the complex affords the alkylated keto ester 522 in 96% yield. Thus functionalization of alkenes is possible by this method. 

Racemic l-methyl-2-butenylboronates (E)- and (Z)-3 may be prepared selectively via reactions of the l-methyl-2-butenyl Grignard reagent with the appropriate borate ester. Use of triisopropyl borate provides a 96 4 mixture of (E)-3l(Z)-3 on a 0.36 mol scale15. Use of a bulkier borylating agent, such as 2-isopropyloxy-4,4,5,5-tetramethyl-l,3,2-dioxaborolane, reverses the selectivity, enabling a 91 9 mixture of (Z)-3/( )-3 to be obtained on a 0.5 mol scale. The diastereomeric purity of this mixture may be enhanced to 95 5 by treatment with 0.15 equivalents of benzaldehyde, since ( )-l-mcthyl-2-butenylboronatc ( )-3 is more reactive than (Z)-3. Repetition of this process provides (Z)-3 that is 98% isomerically pure. 

Sturmer via the reaction of the chiral borate ester (45, 5S)-4,5-dicyclohexyl-2-isopropyloxy-1,3,2-dioxaborolane, and racemic Grignard reagent (l-methyl-2-butenyl)magnesium chloride16. A 97 3 mixture of (S)-4 and its tf-diastereomer was obtained in 89% yield. 

Entry 4 shows the reaction of 9-(E-2-butenyl)-9BBN with methyl pyruvate. This reaction is not very stereoselective, which is presumably due to a modest preference for the orientation of the methyl and methoxycarbonyl groups in the TS. Only use of an extremely sterically demanding pyruvic ester achieved high diastereoselectivity. 

CARBAMIC ACID, (2-METHYL-2-BUTENYL)-, METHYL ESTER, 65, 159... 

Methyl-2-butene 2-Butene, 2-methyl- (513-35-9), 65, 159 (3-Methyl-2-butenyl)propanedioic acid, dimethyl ester ... 

Hethyl-2-butenyl)(2-propynyl)propanedio1c acid, dimethyl ester, 66, 76 Methyl carbamate Carbamic acid, methyl ester (598-55-0), 65, 159 METHYL 4-CHL0R0-2-BUTYN0ATE 2-BUTYNOIC ACID, 4-CHLORO-, METHYL ESTER (41658-12-2), 65, 47... 

Propanedioic acid, diethyl ester (105-53-3), 66, 179 Propanedioic acid, (methoxyraethylene)-, dimethyl ester, 65, 98 Propanedioic acid, (3-methyl-2-butenyl)-, dimethyl ester ... 

Heistcllung und Anwendung von N,N -Bis-[mcthoxycarhonyl]-sulfurdiimid sind fur das Beispicl von dessen Reaktion mit 2-Methyl-2-buten zu N-(2-Methyl-2-butenyl)-carbamidsaure-methylester (43-52%, bezogen auf die Vorstufe des Diimids) ausfiihrlich beschrieben1 Hydrolyse des Esters ergibt dann J-Amino-2-methyl-2-buten. 

CARBAMIC ACID, (2-METHYL-2-BUTENYL)-, METHYL ESTER, 65, 159 Carbamic add, methyl ester, 65,159 Carboalumination of alkynes. 66, 64 Carbocupration of alkynes, 66, 65... 

ICTHYL N-(2- THYL-2-BUTENYL)CARBAMATE (Carbamic acid, (2-methyl-2-butenyI)-, methyl ester)... 

CHLOROPHENOXY)-3-HY0R0XY-1-BUTENYL)-3 5-DIHYOROXYCYCLOPENTYL)- METHYL ESTER, flR-(l-alpha(2E 5Z> 2-beta IE 3R ) 3-alpha 5-alpha))-RN - 62524-99-6 HI - 2.5-HEPTADIENOIC ACID,... 

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