Synthese des Tyrosins

Erlenmeyer, E.; Lipp, A.

doi:10.1002/jlac.18832190203

Cited by 46 publications

(11 citation statements)

References 5 publications

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“…II, No. 6,1979 main reaction consisted of an addition of EtOTf to EG and gave a 1: !-reaction product.…”

Section: Homopolymerization Of Egmentioning

confidence: 99%

“…II, No. 6,1979 more reactive toward 8 and 9 and produces 10 and 11. Under the reaction conditions when [THF] is lower than [M]., 10 and 11 are not attacked by THF and react exclusively with EG.…”

Section: Copolymerization Of Eg With Thfmentioning

confidence: 99%

“…12 Epoxides which have functional groups directly attached to the epoxide rings have been already known. 6 Their synthesis is not particularly easy as it requires trifluoroperacetic acid as the oxidizing It was the. purpose of this work to study the cationic homo-' and co-polymerization of ethyl glycidate, especially the investigation of suitable initiators and conditions for the production of highmolecular-weight homopolymer and copolymer.…”

mentioning

confidence: 99%

“…11, No. 6, 1979 which was supported by the Japan Society for the Promotion of Science and by the National Science Foundation of the U.S.A.…”

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confidence: 99%

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Cationic Homo- and Co-polymerizations of Ethyl Glycidate

Sàegusa

Kobayashi

et al. 1979

Polym J

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ABSTRACT:Cationic homo-and co-polymerizations of ethyl glycidate (EG) have been studied with triethyloxonium tetrafluoroborate (TEOFB) and superacid ester catalysts. The homopolymerization of EG gave a paste-like material of low molecular weight with TEOFB catalyst. A superacid ester catalyst such as ethyl trifluoromethanesulfonate underwent only the initiation process with EG and the propagation was negligibly slow in this system. Copolymerization of EG with tetrahydrofuran (THF) gave a copolymer with TEOFB. When THF remained unreacted after the completion of copolymerization, the copolymer composition was in all cases EG: THF = I : 2. These results were understood in terms of the penultimate effect. The same copolymerization by a superacid ester catalyst, however, always yielded copolymers of the EGITHF= 112 composition. This result was explained in the same way as the TEOFB case, taking the EG polymerizability by a superacid ester into account.KEY WORDS Ethyl Glycidate Cationic PolymerizationCopolymerization I Tetrahydrofuran I Oxonium Salt I Superacid Ester I Penultimate Effect I Cyclic ethers and particularly epoxides have been known for a long time to polymerize to polyethers even of very high molecular weight. 1 • 2 While cyclic ethers polymerize primarily with classical cationic initiators and aluminum and zinc organic compounds by what is often referred to as coordinative anionic polymerization, 3 epoxides undergo polymerization by classical cationic and anionic mechanisms and also by the above mentioned coordinative mechanism. 1 • 2 Most of the work has been done on unsubstituted and methyl-substituted compounds, namely ethylene oxide and propylene oxide; substitutent groups with higher polarity and the functionality have not been studied to any extent. The monomers with the most reactive groups were those with a chloromethyl substitution as, for example, in epichlorohydrin 4 and 3,3-bis(chloromethyl)oxetane. 5 agent, which in turn must be prepared from 90 % H 2 0 2 and trifluoroacetic acid. Glycidaldehyde, 7 glycidyl esters, 8 and glycidonitrile 7 have been prepared; glycidaldehyde was polymerized via both the epoxide group and the aldehyde group, depending on the reaction conditions. 9 These monomers have been copolymerized with trioxane 10 and the properties of co-and ter-polymers with 1,3-dioxolane with a relatively low percentage of glycidate incorporated were investigated. 11 These polymers were then hydrolyzed to the corresponding poly( oxymethylene)ionomers and their free acids. The co-and terpolymerizations were accomplished with classical cationic initiators, both in bulk solution 11 and by a process in which the monomers were mixed in the vapor phase. 12 Epoxides which have functional groups directly attached to the epoxide rings have been already known. 6 Their synthesis is not particularly easy as it requires trifluoroperacetic acid as the oxidizing It was the. purpose of this work to study the cationic homo-' and co-polymerization of ethyl glycidate, especially the investigation of suitab...

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“…II, No. 6,1979 main reaction consisted of an addition of EtOTf to EG and gave a 1: !-reaction product.…”

Section: Homopolymerization Of Egmentioning

confidence: 99%

Section: Copolymerization Of Eg With Thfmentioning

confidence: 99%

mentioning

confidence: 99%

“…11, No. 6, 1979 which was supported by the Japan Society for the Promotion of Science and by the National Science Foundation of the U.S.A.…”

mentioning

confidence: 99%

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Cationic Homo- and Co-polymerizations of Ethyl Glycidate

Sàegusa

Kobayashi

et al. 1979

Polym J

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“…The 2,3-, 2,5-, and 3,4-dinitrotoluenes were recrystallized from alcohol. p-Nitrophenylalanine was prepared from dl-phenylalanine by nitration with fuming nitric acid at 0" according to the directions of Erlenmeyer and Lipp (13). M.p.…”

mentioning

confidence: 99%