Chicle - cis- and trans-Polyisoprenes from a Single Plant Species

Schlesinger, Walter; Leeper, H. M.

doi:10.1021/ie50494a034

Cited by 27 publications

(12 citation statements)

References 4 publications

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“…Fig. 3a indicates the presence of both α and β forms, as represented by two distinguished peaks (95.68 J/g) at Tendo= 64.92 ºC and Tendo= 60.67 ºC, respectively, with predominantly α-form [26,35,40]. Whereas in Fig.…”

Section: Characterization Of the Chicle Gum (Manilkara Zapota) From Ymentioning

confidence: 92%

“…The chicle gum base or crude chicle was purified following a methodology previously described by Schlesinger and Leeper [26]. The inorganic constituents and carbohydrates were separated from the chicle polymers and resin by dissolving the chicle gum in toluene at 25º to 35 ºC, during 24 h with constant stirring.…”

Section: Purification Of Natural Chicle Gummentioning

confidence: 99%

“…For 1,4-trans units, peaks were observed at 600, 801, 1152 and 1325 cm -1 . FT-IR also allowed the identification of the bands related to the α (750, 1030, 1205, 1340, 2872, and 2879 cm -1 ) and β (750, 997, 1212, 1348, 2906, and 2914 cm -1 ) forms of TPI [26,34,38,43].…”

Section: Characterization Of the Chicle Gum (Manilkara Zapota) From Ymentioning

confidence: 99%

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Chicle Gum from sapodilla (Manilkara zapota) as a Renewable Resource for Metathesis Transformations

2018

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In this study, we report on for the first time the self-metathesis of the chicle gum and cross-metathesis of the chicle gum rubber isolated from the gummy latex of sapodilla (Manilkara zapota) with orange oil, β-pinene and, methyl methacrylate using the Ru-alkylidenes Hoveyda-Grubbs and Grubbs second generation catalysts. There were obtained terpene- and ester-terminated oligoisoprenes, with good yields and selectivities. The present results are a promising starting point for the application of this underexploited renewable resource as a new feedstock for metathesis transformations.

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Section: Characterization Of the Chicle Gum (Manilkara Zapota) From Ymentioning

confidence: 92%

Section: Purification Of Natural Chicle Gummentioning

confidence: 99%

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Chicle Gum from sapodilla (Manilkara zapota) as a Renewable Resource for Metathesis Transformations

2018

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“…It has been reported that chicle contains cisand trans-polyisoprenes: 5 the spectrum of isomerized cis-polyisoprene (Figure 1 c). The signals due to the other carbons, however, did not provide any information on the cis-trans sequences.…”

mentioning

confidence: 83%

13C-NMR of Polyisoprenes: Sequence Distribution of cis-1,4 and trans-1,4 Units

Tanaka

Sato

Seimiya

1975

Polym J

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KEY WORDSPolyisoprene 1 1 3C-NMR spectra 1 cis-trans Isomerization I cis-trans Dyad Sequence I Chicle I 13 C-NMR spectroscopy has been applied to analyze the sequence distribution of isomeric structures of diene polymers. Some reports have been published on the sequence distribution of 1,2 and 1,4 units or cis-1,4 and trans-1,4 units in polybutadienes. 1 -3 As for polyisoprene, however, few investigations have been made on the sequence distribution of isomeric structures using this technique, although Duch, et al, reported the assignment of 13 C-NMR signals of the cisand trans-polyisoprenes. 4 In this work, we have studied the 13 C-NMR spectra of cis-trans isomerized 1 ,4-polyisoprenes and found new signals attributed to cis-trans dyad linkage, which enable us to discuss quantitatively the sequence distribution of cis-I ,4 and trans-1,4 units along the polymer chain.Isomerization of polyisoprene (gutta percha and synthetic cis-1 ,4-polyisoprene) was carried out in benzene solution at 20oc under nitrogen atmosphere with the irradiation of a high pressure mercury lamp using thiobenzoic acid as an activator. Natural abundance 13 C-NMR spectra were obtained on a JEOL JNM-PS PFT 100 spectrometer equipped with a Fourier transfer accessory at 25.1 MHz. About 15% (w(v) solution in CDC13 was used. All the spectra were proton noise-decoupled and obtained with multiple scans and with pulse repetition time of 3.0 sec.It has been reported that chicle contains cisand trans-polyisoprenes: 5 thus chicle polyisoprene shows signals at 32.25 and 134.85 ppm due to the cis polymer and at 39.67 and 134.38 ppm 264 due to the trans one (Figure 1 a) PPM FROM T M S Figure 1. 13C-NMR spectra of 1,4-polyisoprenes: (a), chicle polyisoprene; (b), isomerized gutta percha; (c), isomerized cis-1,4-polyisoprene. The symbols Ct and C2 correspond to -QH2-C(CHs)= CH-CH2-and -CH2-Q(CHs)=CH-CH2-, respectively.

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“…Relatively few plant species produce trans -polyisoprene. Those that are able to produce trans -polyisoprene include Mimusops balata (Balata), Palaquium gutta (Gutta percha) [4,5] and Eucommia ulmoides [6-8]. Trans -polyisoprene has several specific properties that differ from those of cis -polyisoprene.…”

Section: Introductionmentioning

confidence: 99%

Overexpression of an isopentenyl diphosphate isomerase gene to enhance trans-polyisoprene production in Eucommia ulmoides Oliver

et al. 2012

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BackgroundNatural rubber produced by plants, known as polyisoprene, is the most widely used isoprenoid polymer. Plant polyisoprenes can be classified into two types; cis-polyisoprene and trans-polyisoprene, depending on the type of polymerization of the isoprene unit. More than 2000 species of higher plants produce latex consisting of cis-polyisoprene. Hevea brasiliensis (rubber tree) produces cis-polyisoprene, and is the key source of commercial rubber. In contrast, relatively few plant species produce trans-polyisoprene. Currently, trans-polyisoprene is mainly produced synthetically, and no plant species is used for its commercial production.ResultsTo develop a plant-based system suitable for large-scale production of trans-polyisoprene, we selected a trans-polyisoprene-producing plant, Eucommia ulmoides Oliver, as the target for genetic transformation. A full-length cDNA (designated as EuIPI, Accession No. AB041629) encoding isopentenyl diphosphate isomerase (IPI) was isolated from E. ulmoides. EuIPI consisted of 1028 bp with a 675-bp open reading frame encoding a protein with 224 amino acid residues. EuIPI shared high identity with other plant IPIs, and the recombinant protein expressed in Escherichia coli showed IPI enzymatic activity in vitro. EuIPI was introduced into E. ulmoides via Agrobacterium-mediated transformation. Transgenic lines of E. ulmoides overexpressing EuIPI showed increased EuIPI expression (up to 19-fold that of the wild-type) and a 3- to 4-fold increase in the total content of trans-polyisoprenes, compared with the wild-type (non-transgenic root line) control.ConclusionsIncreasing the expression level of EuIPI by overexpression increased accumulation of trans-polyisoprenes in transgenic E. ulmoides. IPI catalyzes the conversion of isopentenyl diphosphate to its highly electrophilic isomer, dimethylallyl diphosphate, which is the first step in the biosynthesis of all isoprenoids, including polyisoprene. Our results demonstrated that regulation of IPI expression is a key target for efficient production of trans-polyisoprene in E. ulmoides.

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Chicle - cis- and trans-Polyisoprenes from a Single Plant Species

Cited by 27 publications

References 4 publications

Chicle Gum from sapodilla (Manilkara zapota) as a Renewable Resource for Metathesis Transformations

Chicle Gum from sapodilla (Manilkara zapota) as a Renewable Resource for Metathesis Transformations

13C-NMR of Polyisoprenes: Sequence Distribution of cis-1,4 and trans-1,4 Units

Overexpression of an isopentenyl diphosphate isomerase gene to enhance trans-polyisoprene production in Eucommia ulmoides Oliver

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