New crown-carrier Cα,α-disubstituted glycines derived from α-methyl-(l)-DOPA
摘要:
The side-chain catechol function of alpha-methyl-(L)-DOPA was utilized for the synthesis of a new series of crown-carrier C-alpha,C-alpha-disubstituted glycines. During N-protection of alpha-methyl-(L)-DOPA methyl ester (H-Mdp-OMe) with Boc anhydride, the formation of N,O-di-Boc derivatives was observed. Selective aminolysis of the catechol tert-butyl carbonate group was achieved using pyrrolidine as nucleophile. Treatment of the resulting Boc-Mdp-OMe by Cs2CO3 in MeOH, followed by bis-O-alkylation with cyclization using various polyethyleneglycol ditosylates or catechol-derived bis-polyethyleneglycol ditosylates in DMF at 60degreesC, led to the derivatives Boc-[15-C-5]-Mdp-OMe, Boc-[18-C-6]-Mdp-OMe, Boc-[benzo-18-C-6]-Mdp-OMe, Boc-[benzo-24-C-8]-Mdp-OMe and then after saponification, to the corresponding N-alpha-protected amino acids. The tripeptides Fmoc-Ala-[18-C-6]-Mdp-Ala-OMe and Boc-Aib-[18-C-6]-Mdp-Ala-OMe were prepared in solution by using Ala and Aib UNCAs for coupling at the N terminus of the [18-C-6]-Mdp residue and the EDC/HOAt method for coupling Ala at its C terminus. (C) 2002 Elsevier Science Ltd. All rights reserved.
glutathione to give a colourless adduct identified as 4-S-glutathionyl-5,6-dihydroxyindole (3). In the case of cysteine, the reaction leads to a non aminoacidic condensation product (λ max 422 nm) which was too unstable to be characterized. The analogous adduct derived by reaction of dopachrome methyl ester (9a) with cysteine ethyl ester (10a) could be isolated and formulated as 11a, containing the new
Renal-selective prodrugs for control of renal sympathetic nerve activity in the treatment of hypertension
申请人:G.D. Searle & Co.
公开号:US20030220521A1
公开(公告)日:2003-11-27
Renal-selective prodrugs are described which are preferentially converted in the kidney to compounds capable of inhibiting synthesis of catecholamine-type neurotransmitters involved in renal sympathetic nerve activity. The prodrugs described herein are derived from inhibitor compounds capable of inhibiting one or more of the enzymes involved in catecholamine synthesis, such compounds being classifiable as tyrosine hydroxylase inhibitors, or as dopa-decarboxylase inhibitors, or as dopamine-&bgr;-hydroxylase inhibitors. These inhibitor compounds are linked to a chemical moiety, such as a glutamic acid derivative, by a cleavable bond which is recognized selectively by enzymes located predominantly in the kidney. The liberated inhibitor compound is then available in the kidney to inhibit one or more of the enzymes involved in catecholamine synthesis. Inhibition of renal catecholamine synthesis can suppress heightened renal nerve activity associated with sodium-retention related disorders such as hypertension. Conjugates of particular interest are glutamyl derivatives of dopamine-&bgr;-hydroxylase inhibitors, of which N-acetyl-&ggr;-glutamyl fusaric acid hydrazide (shown below) is preferred.
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Synthesis, Ion Complexation Study, and 3D-Structural Analysis of Peptides Based on Crown-Carrier,Cα-Methyl-L-DOPA Amino Acids
作者:Karen Wright、Rachid Anddad、Jean-François Lohier、Vincent Steinmetz、Michel Wakselman、Jean-Paul Mazaleyrat、Fernando Formaggio、Cristina Peggion、Marta De Zotti、Timothy A. Keiderling、Rong Huang、Claudio Toniolo
DOI:10.1002/ejoc.200700917
日期:2008.3
terminally protected model peptides to the hexamer level, based on four novel, crown-ether containing Cα-methyl-L-DOPA (L-Mdp) aminoacid residues, namely L-Mdp[15-C-5], L-Mdp[18-C-6], L-Mdp[benzo-24-C-8] and L-Mdp[(S)-Binol-20-C-6], combined with either L-Ala or L-Ala/Aib or Gly/Aib, were synthesized by solution methods. An ESI-MS analysis of their alkali metal cation complexation ability was carried out
The side-chain catechol function of alpha-methyl-(L)-DOPA was utilized for the synthesis of a new series of crown-carrier C-alpha,C-alpha-disubstituted glycines. During N-protection of alpha-methyl-(L)-DOPA methyl ester (H-Mdp-OMe) with Boc anhydride, the formation of N,O-di-Boc derivatives was observed. Selective aminolysis of the catechol tert-butyl carbonate group was achieved using pyrrolidine as nucleophile. Treatment of the resulting Boc-Mdp-OMe by Cs2CO3 in MeOH, followed by bis-O-alkylation with cyclization using various polyethyleneglycol ditosylates or catechol-derived bis-polyethyleneglycol ditosylates in DMF at 60degreesC, led to the derivatives Boc-[15-C-5]-Mdp-OMe, Boc-[18-C-6]-Mdp-OMe, Boc-[benzo-18-C-6]-Mdp-OMe, Boc-[benzo-24-C-8]-Mdp-OMe and then after saponification, to the corresponding N-alpha-protected amino acids. The tripeptides Fmoc-Ala-[18-C-6]-Mdp-Ala-OMe and Boc-Aib-[18-C-6]-Mdp-Ala-OMe were prepared in solution by using Ala and Aib UNCAs for coupling at the N terminus of the [18-C-6]-Mdp residue and the EDC/HOAt method for coupling Ala at its C terminus. (C) 2002 Elsevier Science Ltd. All rights reserved.
Catalytic Asymmetric Benzylation of Azomethine Ylides Enabled by Synergistic Lewis Acid/Palladium Catalysis
作者:Xin Chang、Jing-Di Ran、Xue-Tao Liu、Chun-Jiang Wang
DOI:10.1021/acs.orglett.2c00865
日期:2022.4.8
synergistic chiral Lewis acid/achiral Pd catalyst system was successfully applied in the enantioselective benzylation of various imine esters, giving a range of α-benzyl-substituted α-amino acid derivatives in satisfactory yield with excellent enantioselectivity. It is worth noting that this strategy exhibits good tolerance for bicyclic and monocyclic benzylic electrophiles. Furthermore, the utility of this