Syntheses of racemic and non-racemic silicon- and germanium-containing α-amino acids of the formula type H2NCH(CH2ElR3)COOH (El=Si, Ge; R=organyl) and incorporation of d-H2NCH(CH2SiMe3)COOH and d-H2NCH(CH2GeMe3)COOH into biologically active decapeptides: a study on C/Si/Ge bioisosterism
摘要:
Two novel efficient methods for the synthesis of racemic silicon- and germanium-containing a-amino acids of the formula type rac-H2NCH(CH2EIR3)COOH (El = Si, Ge; R = organyl), starting from 3,6-diethoxy-2,5-dihydropyrazine, have been developed. Racemic cc-amino acids synthesized: rac-H2NCH(CH2SiMe3)COOH (rac-2), rac-H2NCH(CH2GeMe3)COOH (rac-3), rac-H2NCH(CH2SiMe2Ph)COOH (rac-4), rac-H2NCH(CH2GeMe2Ph)COOH (rac-5), and rac-H2NCH(CH2SiMe2CH=CH2)COOH (rac-6). Preparative liquid-chromatographic resolution of rac-2 and rac-3 [CHIROBIOTIC T (glycopeptide Teicoplanin covalently linked to spherical silica gel) as the stationary phase] yielded the alpha -amino acids (R)-2, (S)-2, (R)-3, and (S)-3. The (R)- and (S)-enantiomers of beta-(trimethylsilyl)alanine [(R)- and (S)-2] and beta-(trimethylgermyl)alanine I(R)- and (S)-3] are sila-analogs and germa-analogs, respectively, of the antipodes of the non-proteinogenic alpha -amino acid beta -tert-butylalanine [(S)- and (R)-H2NCH(CH2CMe3)COOH; (S)- and (R)-1]. Starting from the N-Fmoc-protected C/Si/Ge-analogous (D-configurated) alpha -amino acids (R)-1, (S)-2, and (S)-3, the C/Si/Ge-analogous decapeptides 7-9 [Ac-D-Nal(1)-4-Cl-D-Phe(2)-D-Pal(3)-Ser(4)-N-Me-Tyr(5)-D-Hci(6)- Nle(7)-Arg(8)-Pro(9)-D-Me(3)El-Ala(10)-NH2 (7, El = C; 8, El = Si; 9, El = Ge)] were prepared by sequential solid-phase synthesis. The decapeptides 7-9 were studied in vitro in a functional assay using a recombinant cell line expressing the human GnRH receptor (agonist Triptorelin). Compounds 7-9 behaved as medium-potent GnRH antagonists, the antagonistic potencies of these three C/Si/Ge analogs being very similar. (C) 2001 Elsevier Science B.V. All rights reserved.
Microbial and Enzymatic Synthesis of Optically Pure D- and L-3-Trimethylsilyl-alanine by Deracemization of D,L-5-Trimethylsilyl-methyl-hydantion
作者:Markus Pietzsch、Thomas Waniek、Richard J. Smith、Svetoslav Bratovanov、Stefan Bienz、Christoph Syldatk
DOI:10.1007/s007060070093
日期:2000.6.15
the action of an aminoacid racemase. Isolated hydantoinases from Bacillus thermoglucosidasius, Thermus sp., Arthrobacter aurescens DSM 3745, and Arthrobacter crystallopoietes DSM 20117 turned out to be stereospecific for the conversion of the D -form of hydantoin D,L - 1 . The enantiomericallypure L -form of 3 was also prepared. It was synthesized from racemic N-carbamoyl aminoacid D,L - 2 by enantiomer-specific
研究了来自不同微生物来源的乙内酰脲酶和N-氨基甲酰基氨基酸酰胺水解酶(N-氨基甲酰酶)的立体特异性,分别合成了非天然含硅氨基酸 D- 和 L -3-trimethylsilyl-alanine( 3 )的立体选择性。 外消旋乙内酰脲 D,L - 1 。在制备性生物转化中, 土壤杆菌属的整个静止细胞 。 固定在海藻酸钙基质中的IP I 671以88%的收率和95%的对映体过量用于氨基酸 D - 3 的合成 。由于纯化的 D -N-氨基甲酰酶来自 农杆菌属 IP I 671被证明是100% D 选择性的,由固定化细胞转化产生的 D - 3 的95%的对映体纯度 必须通过进一步的 L 选择性N-氨基甲酰酶的参与来解释, 或者通过氨基酸外消旋酶的作用使最终水解产物外消旋化的可能性更大。分离自hydantoinases 。thermoglucosidasius芽孢杆菌,栖热菌种,节aurescens
Highly Practical Methodology for the Synthesis of <scp>d</scp>- and <scp>l</scp>-α-Amino Acids, <i>N</i>-Protected α-Amino Acids, and <i>N</i>-Methyl-α-amino Acids
作者:Andrew G. Myers、James L. Gleason、Taeyoung Yoon、Daniel W. Kung
DOI:10.1021/ja9624073
日期:1997.1.1
step the asymmetric alkylation of pseudoephedrine glycinamide (1) or pseudoephedrine sarcosinamide (2). Practical procedures for the synthesis of 1 and 2 from pseudoephedrine and glycine methyl ester or sarcosinemethyl ester, respectively, are presented. Optimum protocols for the enolization and subsequent alkylation of 1 and 2 are described. Alkylation reactions of 1 and 2 are found to be quite efficient
Syntheses of racemic and non-racemic silicon- and germanium-containing α-amino acids of the formula type H2NCH(CH2ElR3)COOH (El=Si, Ge; R=organyl) and incorporation of d-H2NCH(CH2SiMe3)COOH and d-H2NCH(CH2GeMe3)COOH into biologically active decapeptides: a study on C/Si/Ge bioisosterism
Two novel efficient methods for the synthesis of racemic silicon- and germanium-containing a-amino acids of the formula type rac-H2NCH(CH2EIR3)COOH (El = Si, Ge; R = organyl), starting from 3,6-diethoxy-2,5-dihydropyrazine, have been developed. Racemic cc-amino acids synthesized: rac-H2NCH(CH2SiMe3)COOH (rac-2), rac-H2NCH(CH2GeMe3)COOH (rac-3), rac-H2NCH(CH2SiMe2Ph)COOH (rac-4), rac-H2NCH(CH2GeMe2Ph)COOH (rac-5), and rac-H2NCH(CH2SiMe2CH=CH2)COOH (rac-6). Preparative liquid-chromatographic resolution of rac-2 and rac-3 [CHIROBIOTIC T (glycopeptide Teicoplanin covalently linked to spherical silica gel) as the stationary phase] yielded the alpha -amino acids (R)-2, (S)-2, (R)-3, and (S)-3. The (R)- and (S)-enantiomers of beta-(trimethylsilyl)alanine [(R)- and (S)-2] and beta-(trimethylgermyl)alanine I(R)- and (S)-3] are sila-analogs and germa-analogs, respectively, of the antipodes of the non-proteinogenic alpha -amino acid beta -tert-butylalanine [(S)- and (R)-H2NCH(CH2CMe3)COOH; (S)- and (R)-1]. Starting from the N-Fmoc-protected C/Si/Ge-analogous (D-configurated) alpha -amino acids (R)-1, (S)-2, and (S)-3, the C/Si/Ge-analogous decapeptides 7-9 [Ac-D-Nal(1)-4-Cl-D-Phe(2)-D-Pal(3)-Ser(4)-N-Me-Tyr(5)-D-Hci(6)- Nle(7)-Arg(8)-Pro(9)-D-Me(3)El-Ala(10)-NH2 (7, El = C; 8, El = Si; 9, El = Ge)] were prepared by sequential solid-phase synthesis. The decapeptides 7-9 were studied in vitro in a functional assay using a recombinant cell line expressing the human GnRH receptor (agonist Triptorelin). Compounds 7-9 behaved as medium-potent GnRH antagonists, the antagonistic potencies of these three C/Si/Ge analogs being very similar. (C) 2001 Elsevier Science B.V. All rights reserved.