Methyl Trans-cinnamate Research Articles

O-Silylierte Phosphinoketenacetale RR′PCH2CH=C(OSiMe3)OR″. Darstellung und Hydrolyse zu Phosphinoestern / O -Silylated Phosphinoketenacetals RR′PCH2CH = C(O SiMe3)OR″. Preparation and Hydrolysis to Phosphinoesters

Trimethylsilyl phosphines Ph(R)PSiMe3 (R = Me, Et, Pr, Bu, iBu, and C5H11) react with acrylic esters CH2 = C(R′)CO2Me(R′ = H, Me) to give the O-silylated phosphinoketenacetals Ph(R)PCH2C(R′)=C(OSiMe3)OMe 1-6, 15 and 16. By contrast, the reactions of the sterically demanding silyl phosphines R2PSiMe3 (R = iPr, tBu) with CH2= CHCO2R′ (R′ = Me, Et) result in the formation of mixtures of the corresponding phosphinoketenacetals 7-10 and the 1,2-addition products R2PCH2CH(SiMe3)CO2R′ 11-14. The ratio of the two isomers depends on the solvent and on the reaction temperature. β-Substituted acrylic acid esters such as methyl trans-crotonate or methyl trans-cinnamate react only very slowly (yielding a mixture of compounds) or do not react at all. NMR spectra and NOE measurements reveal that only the Z-isomer of the O-silylated phosphinoketenacetals is formed. On the basis of these results a plausible reaction mechanism is proposed. The phosphinoketenacetals react with H2O to afford the phosphinoesters R(R′)PCH2CH2CO2R″ 17-22, and with D2O to give the deuterated species R(R′)PCH2CHDCO2Me 23 and 24.

Hydrogen-bonded complexes of α,β-unsaturated carboxylic esters with phenols: a molecular mechanics study

The hydrogen-bonded complexes between phenol derivatives and methyl acrylate, methyl trans-crotonate and methyl trans-cinnamate were studied using the interactive molecular modelling program PCMODEL which uses the features of Allinger's MMX force field, including pi-valence electron self-consistent field (Pi-VESCF) calculations. The results successfully reproduce experimental Δ H values associated with the formation of the hydrogen-bonded complexes and account for the experimentally observed dependences of Δ H on the electron releasing/withdrawing abilities of the substituents in the phenol aromatic ring or in the ester. In addition, the conformational change in the ester moiety of the hydrogen-bonded complexes gives rise to energetically similar hydrogen bonds, in agreement with previous infrared spectroscopic results. In general, the results obtained confirm or expand the previous spectroscopic or quantum mechanical results of M. Dulce G. Faria (J. Mol. Struct., 263 (1991) 87; Vib. Spectrosc., 2 (1991) 43, 107), and lead to the possibility of successfully applying the MMX/Pi-VESCF method to the study of hydrogen-bonded complexes involving other biochemically important molecules.

Hydrogen bonding involving α,β-unsaturated carboxylic esters and substituted phenols: an infrared spectroscopic study

The hydrogen-bonded complexes between phenol derivatives and methyl acrylate, methyl trans- crotonate and methyl trans-cinnamate were studied in carbon tetrachloride solution by infrared spectroscopy. Temperature variation studies were used to evaluate both formation constants and the enthalpies of complex formation. It is shown that the relative values of enthalpies associated with the hydrogen bonding process in the various systems studied depend on the substituent constants of both the ester and phenol substituents. In addition, it is also shown that the observed shifts in the carbonyl stretching frequency upon complexation can be correlated with Δ H, thus providing a useful indirect way of measuring the strength of the hydrogen bond.

Synthesis of enantio- and diastereo-isomerically pure β- and γ-substituted glutamic acids via glycine condensation with activated olefins

The glycine fragment in the nickel(II) complex formed from the Schiff base of glycine and (S)-o[(N-benzylprolyl)amino]benzophenone undergoes base-catalysed Michael addition in methanol in the presence of MeONa to the activated olefins methyl acrylate, acrylonitrile, methyl methacrylate, acrolein, and methyl trans-cinnamate. Complexes of substituted (S)-glutamic acid or its derivatives were formed in good chemical yields with almost complete diastereoselection at the α-carbon atom of the amino acid moiety. Diastereoselection at the β- and γ-atoms was not significant, but the isomeric complexes could be easily separated chromatographically. Cleavage of the pure diastereo-isomers with aqueous HCl gave, in good yields, optically pure glutamic acids and regenerated the original chiral reagent. The configurations of the amino acid β- and γ-carbon atoms were determined by 1H n.m.r. spectroscopy and crystal structure X-ray analysis of the corresponding original complexes. The addition to acrolein, catalysed by triethylamine in methanol, leads to the 1,4-adduct exclusively. The amino acid thus obtained could be converted into (S)-proline by reduction with NaBH4.

Reactions of iodine(I) azide with αβ-unsaturated carbonyl compounds

The addition of iodine(I) azide to some αβ-unsaturated esters and ketones has been examined. Addition to the esters under nitrogen gives products consistent with a radical pathway. Preliminary kinetic results indicate that addition of iodine(I) azide to αβ-unsaturated ketones in the presence of air involves a slow electrophilic attack. Reaction with methyl trans-cinnamate under these conditions does not go to completion.

Aromatization of arene 1,2-oxides. 1,2-Oxides of methyl phenylacetate and methyl trans-cinnamate

Aromatization of arene 1,2-oxides. 1,2-Oxides of methyl phenylacetate and methyl trans-cinnamate

Cis-trans Photoisomerization in Tri-Ortho-Thymotide Inclusion Complexes: Crystal Structures of cis- and trans- Stilbene TOT Clathrates

Abstract New clathrate inclusion complexes of tri-ortho-thymotide (TOT) with cis-stilbene, trans-stilbene, methyl cis-cinnamate, methyl trans-cinnamate, and with other ethylene derivatives, have been prepared and characterized. In the triclinic crystal structure of the TOT-trans-stilbene inclusion complex (space group PT), each unit cell contains four TOT and two trans-stilbene molecules. Two pairs of TOT molecules are related to each other by a center of symmetry and both stilbene moiecuies are located in special positions on these centers. The stilbene guests occupy two different channels which are perpendicular to one another (see Figure 1).

Structure and reactivity of theobrominate and theophyllinate complexes with methyl trans-cinnamate

The structure of the methyl trans-cinnamate complexes with the theophylline and theobromine anions is calculated theoretically by maximizing the binding energy of the two interacting molecules. The binding energy is calculated using the monopoles-bond polarizabilities method. The predicted structures correlate well with observed reactivity of the ester in the two complexes.

Stereochemistry of the Cycloaddition of Singlet Excited β-Substituted Styrenes to Olefins

The photocycloaddition of β-substituted styrenes (trans-cinnamic acid (1b), methyl trans-cinnamate (1c), trans-cinnamonitrile (1d), and cis-cinnamonitrile) to olefins occurs with retention of stereochemistry and involves the S1 state. In certain cases (1b, c) a photoene reaction competes with the cycloaddition. The triplet states of the β-substituted styrenes produced by sensitization give only [Formula: see text] isomerization. Neither cycloadduct nor photoene reaction is observed from the triplet states. It is thus likely that both addition and photoene reactions involve the S1 state of the β-substituted styrene.

Kinetic Salt Effects upon Chlorinations in Anhydrous Acetic Acid as the Solvent

Chlorination reactions in anhydrous or glacial acetic acid as the solvent occur at room temperature through the combination of the soft acid, C12, with various soft bases: linear pentenes (10); methyl transcinnamate (3); and 4-substituted arenesulfenyl chlorides (5). The kinetics for the normal chlorinations involve a first order dependence upon the halogen and on the soft base, and in each case the proposed mechanisms postulate ionic chlorine-containing species as the intermediate. The overall process can be formalized by equation 1.

Chlorination of αβ-unsaturated carbonyl compounds. Part IV. Kinetics and mechanism of the uncatalysed and hydrogen chloride catalysed chlorination of trans-cinnamaldehyde in acetic acid

The reaction of chlorine with trans-cinnamaldehyde in acetic acid is strongly catalysed by hydrogen chloride. In the absence of added hydrogen chloride the chlorination is autocatalysed by the hydrogen chloride liberated during the reaction. In the presence of sufficient added alkali-metal acetate, the autocatalysis is suppressed and the uncatalysed reaction takes place. The uncatalysed reaction gives both acetoxy-chlorides and dichlorides, and the mechanism is similar to that observed with methyl trans-cinnamate and trans-cinnamic acid, except that there is also ca. 40% side-chain substitution. The hydrogen chloride catalysed reaction involves the chlorination of the small equilibrium concentration of the 1,4-adduct of trans-cinnamaldehyde and hydrogen chloride, i.e., the enol of β-chloro-β-phenylpropionaldehyde. The products of this reaction are entirely dichlorides with a preponderance of the erythro-isomer, in marked contrast to the uncatalysed reaction in which the main addition products are threo-dichloride and erythro-acetoxy-chloride.

Chlorination of αβ-unsaturated carbonyl compounds. Part III. Reaction of chlorine with trans-cinnamic acid and the trans-cinnamate ion

The addition of chlorine to trans-cinnamic acid in acetic acid and in acetic acid containing lithium chloride, lithium perchlorate, or perchloric acid is very similar to that observed for methyl trans-cinnamate. A similar mixed mechanism, involving a direct addition of chlorine and collapse of, and reaction of the solvent with, an ion-pair and chloronium ions, is proposed. No acid-catalysis other than a salt effect is observed. In acetic acid containing lithium acetate, the addition products are accompanied by trans-β-chlorostyrene, 1,2,2-trichloroethylbenzene, and 1-acetoxy-2,2-dichloroethylbenzene. The chlorostyrene is formed by a direct reaction of the trans-cinnamate ion with chlorine, and not by elimination of carbon dioxide from the addition products or from the intermediate ion-pairs. The ethylbenzene derivatives are formed by further chlorination of the chlorostyrene. The trans-cinnamate ion also undergoes chlorodecarboxylation in aqueous solution, whereas trans-cinnamic acid undergoes addition of hypochlorous acid (or chlorine monoxide) or of chlorine, depending upon the method of mixing the reagents.

Chlorination of αβ-unsaturated carbonyl compounds. Part II. The mechanism of chlorination of para-substituted methyl cis- and trans-cinnamates in acetic acid

The stereochemistry of addition of chlorine or the elements of chlorine acetate to a series of para-substituted methyl cis- and trans-cinnamates in acetic acid has been determined. At least three different mechanisms have been identified; chloronium ion intermediates are favoured with electron-poor olefins, relatively stable and selective ion-pairs predominate with more nucleophilic olefins, and some direct cis-addition of chlorine is observed over the entire range. A previous interpretation of the mechanism of chlorine addition to methyl trans-cinnamate overestimated the contribution of ion-pair intermediates.

Chlorination of αβ-unsaturated carbonyl compounds. Part I. The addition of chlorine to methyl trans-cinnamate in acetic acid

The kinetics and products of the chlorination of methyl trans-cinnamate in acetic acid alone and in acetic acid containing lithium acetate, lithium chloride, lithium perchlorate, or perchloric acid have been studied. The acid has no effect on the rate other than can be attributed to an increase in the ionic strength. The results indicate that the reaction involves the attack of a highly polarised chlorine molecule on the olefin, which leads to an ion-pair that exists in two conformations; these, though readily interconvertible, have the characteristics of diastereoisomers. Methyl threo-αβ-dichloro-β-phenylpropionate is formed by the collapse of one conformation and the erythro-isomer is formed by the collapse of the other. In the presence of lithium chloride, both isomers are also formed by capture of the appropriate conformations by the added chloride ion. The main effect of added electrolytes is to increase the yield of acetoxy-chlorides which are formed by attack of the solvent on the two ion-pair conformations. There is no evidence for a direct chlorination. Dechlorination and deacetoxychlorination of the addition products with chromous sulphate in aqueous dimethylformamide gives methyl trans-cinnamate together with a small amount of the cis-isomer, indicating that this method of dechlorination of these compounds is nonstereospecific.

Modification of reaction rates by complex formation. II. Inhibition of the rate of alkaline hydrolysis of methyl trans-cinnamate by some heterocyclic compounds.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModification of Reaction Rates by Complex Formation. II. Inhibition of the Rate of Alkaline Hydrolysis of Methyl trans-Cinnamate by Some Heterocyclic CompoundsJoseph A. Mollica and Kenneth A. ConnorsCite this: J. Am. Chem. Soc. 1967, 89, 2, 308–317Publication Date (Print):January 1, 1967Publication History Published online1 May 2002Published inissue 1 January 1967https://doi.org/10.1021/ja00978a025RIGHTS & PERMISSIONSArticle Views119Altmetric-Citations20LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts