Synthesis of Novel Nonproteinogenic Amino Acids: <i>N</i>‐Ethyl‐α,β‐dehydroamino Acid Methyl Esters

Monteiro, Luís S.; Kołomańska, Joanna; Suárez, Ana C.

doi:10.1002/ejoc.201001302

Cited by 6 publications

(7 citation statements)

References 17 publications

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“…To expand the scope of the procedure for N ‐ethylation of dehydroamino acid derivatives previously reported,19 attempts at alkylating dehydroamino acids with amine protecting groups other than the 4‐nitrophenylsulfonyl group were carried out. Thus, the methyl esters of N ‐( tert ‐butyloxycarbonyl)dehydroalanine (Boc‐ΔAla‐OMe) and of N ‐(4‐nitrobenzyloxycarbonyl)dehydroalanine [Z(NO 2 )‐ΔAla‐OMe] were subjected to N ‐ethylation with triethyloxonium tetrafluoroborate.…”

Section: Resultsmentioning

confidence: 99%

“…For the Nosyl derivatives, dehydration had to be carried out using 2 equiv. of tert ‐butyl pyrocarbonate to give the corresponding N ‐Boc and N ‐Nosyl dehydroamino acid derivatives, followed by treatment with a 4 % solution of trifluoroacetic acid in dichloromethane to give compounds 2f and 3f 19. The dehydroamino acid derivatives were treated with 1.2 equiv.…”

Section: Resultsmentioning

confidence: 99%

“…Methyl Esters of N ‐Protected β ‐Hydroxy Amino Acids: Z(NO 2 )‐ L ‐Ser‐OMe,17 Z‐ L ‐Ser‐OMe,17 Boc‐ L ‐Ser‐OMe,17 2‐Fur‐ L ‐Ser‐OMe,21 Bz(4‐OMe)‐ L ‐Ser‐OMe,21 Z(NO 2 )‐ L ‐Thr‐OMe,17 Z‐ L ‐Thr‐OMe,17 Boc‐ L ‐Thr‐OMe,17 Nosyl‐ L ‐Thr‐OMe,19 Tos‐ L ‐Thr‐OMe,17 Z(NO 2 )‐ D , L ‐Phe(β‐OH)‐OMe,17 Boc‐ D , L ‐Phe(β‐OH)‐OMe,22 Nosyl‐ D , L ‐Phe(β‐OH)‐OMe,19 Tos‐ D , L ‐Phe(β‐OH)‐OMe;18 the synthesis of these compounds has been described previously.…”

Section: Methodsmentioning

confidence: 99%

“…Methyl Esters of N ‐( tert ‐Butoxycarbonyl) N ‐(4‐Nitrophenylsulfonyl) α,β‐Dehydroamino Acids: The synthesis of Nosyl‐ Z ‐ΔAbu( N ‐Boc)‐OMe19 and Nosyl‐ Z ‐ΔPhe( N ‐Boc)‐OMe19 have been described previously.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we reported the use of a combination of the alkylation procedure reported by Liguori et al12 and our dehydration methodologies17,18 to obtain new non‐proteinogenic amino acids, namely, N ‐(4‐nitrophenylsulfonyl) N ‐ethyl α,β‐dehydroamino acids 19. Thus, it was possible to obtain for the first time, new non‐natural amino acids that incorporate both the N ‐ethyl and the α,β‐dehydro moieties.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of New N‐Ethyl Dehydroamino Acid Derivatives: N‐Ethyl β,β‐Dibromo, N‐Ethyl β‐Bromo β‐Substituted, and N‐Ethyl β,β‐Disubstituted N‐Protected Dehydroamino Acid Methyl Esters

2011

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Recently, we reported the use of a sequence of alkylation and dehydration methodologies to obtain new non‐proteinogenic amino acids (N‐ethyl α,β‐dehydroamino acids) from the methyl esters of N‐(4‐nitrophenylsulfonyl) β‐hydroxy amino acids. Thus, it was possible to obtain for the first time, non‐natural amino acids that incorporate both N‐ethyl and α,β‐dehydro moieties. Herein, we report the application of this N‐alkylation procedure to several methyl esters of β,β‐dibromo and β‐bromo β‐substituted dehydroamino acids protected with standard amine protecting groups such as tert‐butyloxycarbonyl, benzyloxycarbonyl, and (4‐nitrobenzyl)oxycarbonyl, as well as acyl and sulfonyl groups. The procedure allows the synthesis of the methyl esters of N‐protected N‐ethyl β,β‐dibromo and N‐ethyl β‐bromo β‐substituted dehydroamino acids in fair to high yields. Some of these N‐ethylated dehydroamino acid derivatives were used as substrates in cross‐coupling reactions to give β,β‐disubstituted N‐ethyldehydroalanine derivatives.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Synthesis of New N‐Ethyl Dehydroamino Acid Derivatives: N‐Ethyl β,β‐Dibromo, N‐Ethyl β‐Bromo β‐Substituted, and N‐Ethyl β,β‐Disubstituted N‐Protected Dehydroamino Acid Methyl Esters

2011

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High yielding synthesis of N-ethyl dehydroamino acids

Monteiro

Suárez

2012

Amino Acids

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Recently we reported the use of a sequence of alkylation and dehydration methodologies to obtain N-ethyl-α, β-dehydroamino acid derivatives. The application of this N-alkylation procedure to several methyl esters of β,β-dibromo and β-bromo, β-substituted dehydroamino acids protected with standard amine protecting groups was subsequently reported. The corresponding N-ethyl, β-bromo dehydroamino acid derivatives were obtained in fair to high yields and some were used as substrates in Suzuki cross-coupling reactions to give N-ethyl, β,β-disubstituted dehydroalanine derivatives. Herein, we further explore N-ethylation of β-halo dehydroamino acid derivatives using triethyloxonium tetrafluoroborate as alkylating agent, but substituting N,N-diisopropylethylamine for potassium tert-butoxide as auxiliary base. In these conditions, for all β-halo dehydroamino acid derivatives, reactions were complete and the N-ethylated derivative could be isolated in high yield. This method was also applied for N-ethylation of non-halogenated dehydroamino acids. Again, with all compounds the reactions were complete and the N-ethyl dehydroamino acid derivatives could be isolated in high yields. Some of these N-ethyl dehydroamino acid methyl ester derivatives were converted in high yields to their corresponding acids and coupled to an amino acid methyl ester to give N-ethyl dehydrodipeptide derivatives in good yields. Thus, this method constitutes a general procedure for high yielding synthesis of N-ethylated dehydroamino acids, which can be further applied in peptide synthesis.

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Intra- and intermolecular forces dependent main chain conformations of esters of α,β-dehydroamino acids

Siodłak¹,

Bujak²,

Staś³

2013

Journal of Molecular Structure

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Synthesis of Novel Nonproteinogenic Amino Acids: N‐Ethyl‐α,β‐dehydroamino Acid Methyl Esters

Cited by 6 publications

References 17 publications

Synthesis of New N‐Ethyl Dehydroamino Acid Derivatives: N‐Ethyl β,β‐Dibromo, N‐Ethyl β‐Bromo β‐Substituted, and N‐Ethyl β,β‐Disubstituted N‐Protected Dehydroamino Acid Methyl Esters

Synthesis of New N‐Ethyl Dehydroamino Acid Derivatives: N‐Ethyl β,β‐Dibromo, N‐Ethyl β‐Bromo β‐Substituted, and N‐Ethyl β,β‐Disubstituted N‐Protected Dehydroamino Acid Methyl Esters

High yielding synthesis of N-ethyl dehydroamino acids

Intra- and intermolecular forces dependent main chain conformations of esters of α,β-dehydroamino acids

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