- An Atom-Economic Inverse Solid-Phase Peptide Synthesis Using Bn or BcM Esters of Amino Acids
-
An atom-economic N-to-C-directed solid-phase peptide synthesis is reported that uses benzyl (Bn) or (benzhydryl-carbamoyl)-methyl (BcM) esters of amino acids as the building blocks, which facilitate efficient hydrazinolysis, convenient conversion to acyl azide, and robust amidation with the next amino acid ester. This method is free of coupling reagents and free of protection on the side-chain OH, CO2H, CONH2, etc., therefore exhibiting a significantly improved atom economy compared to those of BOC- or Fmoc-based C-to-N-directed approaches.
- Huang, Wei,Li, Jian,Liu, Bo,Tang, Feng,Zheng, Xing,Zhu, Yue
-
supporting information
p. 7571 - 7574
(2021/10/02)
-
- Green Esterification of Carboxylic Acids Promoted by tert-Butyl Nitrite
-
In this work, the green esterification of carboxylic acids promoted by tert-butyl nitrite has been well developed. This transformation is compatible with a broad range of substrates and exhibits excellent functional group tolerance. Various drugs and substituted amino acids are applicable to this reaction under near neutral conditions, with good to excellent yields.
- Cheng, Xionglve,Jiang, Gangzhong,Li, Xingxing,Tao, Suyan,Wan, Xiaobing,Zhao, Yanwei,Zheng, Yonggao
-
supporting information
p. 2713 - 2718
(2021/06/25)
-
- An efficient, stereocontrolled and versatile synthetic route to bicyclic partially saturated privileged scaffolds
-
Herein, we describe the development of a simple, high yielding and stereocontrolled strategy for the synthesis of a series of triazolopiperazines and other biologically relevant fused scaffolds from optically active amino acids. This route was applied to the synthesis of 22 scaffolds containing new, previously inaccessible vectors and used to access a novel analogue of ganaplacide.
- Bond, Andrew D.,Hanby, Abigail R.,King, Thomas A.,Moss, Thomas A.,Sore, Hannah F.,Spring, David R.,Stewart, Hannah L.
-
supporting information
p. 6818 - 6821
(2020/07/04)
-
- α-Amino Aldehydes as Readily Available Chiral Aldehydes for Rh-Catalyzed Alkyne Hydroacylation
-
Readily available α-amino aldehydes, incorporating a methylthiomethyl (MTM) protecting group on nitrogen, are shown to be efficient substrates in Rh-catalyzed alkyne hydroacylation reactions. The reactions are performed under mild conditions, employing a small-bite-angle bis-phosphine ligand, allowing for good functional group tolerance with high stereospecificity. Amino aldehydes derived from glycine, alanine, valine, leucine, phenylalanine, isoleucine, serine, tryptophan, methionine, and cysteine were successfully employed, as was an enantiomerically enriched α-OMTM-aldehyde derived from phenyllactic acid. The synthetic utility of the α-amino enone products is demonstrated in a short enantioselective synthesis of the natural product sphingosine.
- Hooper, Joel F.,Seo, Sangwon,Truscott, Fiona R.,Neuhaus, James D.,Willis, Michael C.
-
supporting information
p. 1630 - 1634
(2016/02/20)
-
- Synthesis and applications in Henry reactions of novel chiral thiazoline tridentate ligands
-
Several novel chiral tridentate ligands containing thiazoline were efficiently synthesized from commercially available l=cysteine in high yield. These ligands were subsequently applied to the asymmetric Henry reaction of nitromethane and various aldehydes. It was found that the structures of the thiazoline ligands had a significant influence on the enantioselectivity. It was shown that the optimal catalyst for this reaction was a ligand complexed with CuCl, which was formed from chiral thiazoline with chiral aminoalcohol. At -20°C, with 10 mol% of this ligand, a product with (S)-configuration was isolated in 93% yield and 98% enantiomeric excess.
- Shi, Ye,Li, Yang,Sun, Jingbo,Lai, Qi,Wei, Chiyu,Gong, Zhiyong,Gu, Qiang,Song, Zhiguang
-
p. 661 - 667
(2015/09/28)
-
- PEPTIDOMIMETIC COMPOUNDS AND ANTIBODY-DRUG CONJUGATES THEREOF
-
This invention relates to peptidomimetic linkers and anti-body drug conjugates thereof, to pharmaceutical compositions containing them, and to their use in therapy for the prevention or treatment of cancer.
- -
-
-
- N-Urethane protection of amines and amino acids in an ionic liquid
-
An efficient, solvent-free protocol for the N-fluorenylmethoxycarbonylation and N-benzyloxycarbonylation of amines is described. The reaction of aliphatic and aromatic amines with FmocOSu and Cbz-Osu in [Bmim][BF4] at room temperature afforded the corresponding N-urethane derivatives in excellent yields and do not require any further purification. The method has been extended to the N-Fmoc and N-Cbz protection of amino acids. Absence of bases, very short reaction times, high yields, selectivity and ease of product separation are some advantages of this protocol.
- Di Gioia,Gagliardi,Leggio,Leotta,Romio,Liguori
-
p. 63407 - 63420
(2015/08/11)
-
- Mild construction of 3-methyl tetramic acids enabling a formal synthesis of palau'imide
-
A general method to construct 3-methyl-4-O-methylated tetramic acids displaying a C-5 stereocenter is presented. The synthetic sequence employs a SmI2-mediated cyclization, whereby the chirality of the emerging tetramic acid core is retained from the starting chiral amino acid. Application to palau'imide is discussed.
- Bai, Wen-Ju,Jackson, Stephen K.,Pettus, Thomas R. R.
-
supporting information; experimental part
p. 3862 - 3865
(2012/09/22)
-
- A favorable, narrow, δh Hansen-parameter domain for gelation of low-molecular-weight amino acid derivatives
-
In recent years, the design of new low-molecular-weight gelators (LMWGs) has attracted considerable attention because of the interesting supramolecular architectures as well as industrial applications. In this context, the role of the organic solvent in d
- Curcio, Pasquale,Allix, Florent,Pickaert, Guillaume,Jamart-Gregoire, Brigitte
-
scheme or table
p. 13603 - 13612
(2012/01/05)
-
- PROCESS FOR PREPARING ENANTIOMERICALLY ENRICHED AMINO-ALCOHOLS
-
A process for preparing an enantiomerically enriched amino alcohol or derivatives thereof having the structure: wherein C* is a chiral carbon atom and R1 and R2 are independently selected from hydrogen, alkyl, alkoxy, aryl and a peptide chain, wherein said process includes the steps of: (a) providing an amino acid having the structure of Formula I: (b) protecting the amino group of the Formula I amino acid with a carbobenzoxy(Cbz) N-protecting group by reacting the amino acid with benzyl chloroformate in the presence of a base; (c) forming a carboxylic acid alkyl ester of the Cbz N-protected Formula I amino acid by reacting the amino acid with a C1-12 alcohol; and (d) reducing the Cbz N-protected amino acid ester with a borohydride reducing agent in an organic solvent or mixture of organic solvents to form a Cbz N-protected amino-alcohol
- -
-
Page/Page column 3
(2010/07/08)
-
- Addition of allylzinc to a-amino acid-derived imines: Synthesis of diamino alcohols by Hydroboration
-
Imines obtained by condensation of Z-pro- tected or Boc-protected α-amino aldehydes with α-amino tert-butyl esters or with O-silyl-protected amino alcohols were reacted with preformed allyl zinc yielding homoal- lylamines with yields around 50% and selectivities ranging from 50:50 to 90:10. Hydroboration of the terminal double bond furnished diamino alcohols with yields up to 97%. The configuration of the substrates was determined by X-ray-crystallographic analysis of a hydroboration product and comparison of physical data. Springer-Verlag 2010.
- Virlouvet, Mickael,Goesmann, Helmut,Feldmann, Claus,Podlech, Joachim
-
scheme or table
p. 177 - 198
(2010/08/05)
-
- A family of strong low-molecular-weight organogelators based on aminoacid derivatives
-
A new family of potent aminoacid-type organogelators obtained via an easy and unexpensive way is described. We demonstrated that structural variations onto the side chains of the aminoacid derivatives allowed modulations of the gelation properties. The or
- Brosse, Nicolas,Barth, Danielle,Jamart-Grégoire, Brigitte
-
p. 9521 - 9524
(2007/10/03)
-
- First Practical Protection of α-Amino Acids as N, N-Benzyloxycarbamoyl Derivatives
-
The consecutive treatment of N-Cbz amino protected compounds with LiHMDS and CbzCl provides a practical method for the preparation of N,N-benzyloxycarbamoyl (N,N-di-Cbz) derivatives in good yield. When α-amino acids are used the protection occurs without racemization. The method is compatible with a wide range of other functional and protecting groups. The procedure is also valid for the synthesis of mixed N,N-carbamoyl derivatives.
- Hernandez, J. Nicolas,Martin, Victor S.
-
p. 3590 - 3592
(2007/10/03)
-
- Efficient Cs2CO3-promoted solution and solid phase synthesis of carbonates and carbamates in the presence of TBAI
-
Novel solution and solid-phase methods for the synthesis of carbonates and carbamates were developed using cesium bases and TBAI via a three-component coupling. Cesium carbonate not only promoted successful carbonylations of alcohols and carbamations of amines, but also suppressed common side reactions traditionally seen using existing protocols. Various alcohols and amines were examined, using a wide array of alkyl halides, and the results demonstrated this methodology was highly chemoselective. In particular, use of either sterically demanding substrates or amino acid derivatives afforded the corresponding products exclusively, offering a wide variety of applications such as novel protecting groups and peptidomimetic syntheses.
- Salvatore, Ralph N,Chu, Feixia,Nagle, Advait S,Kapxhiu, Elona A,Cross, Richard M,Jung, Kyung Woon
-
p. 3329 - 3347
(2007/10/03)
-
- Broadening of the substrate tolerance of α-chymotrypsin by using the carbamoylmethyl ester as an acyl donor in kinetically controlled peptide synthesis
-
In the kinetically controlled approach of peptide synthesis mediated by α-chymotrypsin, the broadening of the protease's substrate tolerance is achieved by switching the acyl donor from the conventional methyl ester to the carbamoylmethyl ester. Thus, as a typical example, the extremely low coupling efficiency obtained by employing the methyl ester of an inherently poor amino acid substrate, Ala, is significantly improved by the use of this particular ester. Its ameliorating effect is observed also in the couplings of other amino acid residues such as Gly and Ser as carboxy components.
- Miyazawa, Toshifumi,Tanaka, Kayoko,Ensatsu, Eiichi,Yanagihara, Ryoji,Yamada, Takashi
-
-
- A solid-phase approach to analogues of the antibiotic mureidomycin
-
A library of 80 analogues of the antibacterial compound mureidomycin was prepared using solid-phase chemistry techniques. (C) 2000 Elsevier Science Ltd.
- Bozzoli, Andrea,Kazmierski, Wieslaw,Kennedy, Gordon,Pasquarello, Alessandra,Pecunioso, Angelo
-
p. 2759 - 2763
(2007/10/03)
-
- Isocyanates, Part 4.10 Convenient Phosgene-Free Method for the Synthesis and Derivatization of Enantiopure α-Isocyanato Carboxylic Acid Esters
-
A novel phosgene-free procedure for the synthesis of α-isocyanato carboxylic acid esters starting from α-amino acid esters has been achieved. The isocyanates are obtained enantiomerically pure (> 99% ee) by a DMAP-catalyzed isocyanation with di-tert-butyl
- Kn?lker, Hans-Joachim,Braxmeier, Tobias
-
p. 925 - 928
(2007/10/03)
-
- Conversion of carbonimidodithioates to carbamates
-
Carbonimidodithioates derived from primary amines or α-amino acid esters have been converted to N-benzyloxycarbonyl derivatives under mild conditions by treatment first with sodium benzyl alcoholate and then with water. N-Benzyloxycarbonyl α-amino acids have been generated from the methyl esters by alkaline hydrolysis or from the allyl esters by Pd0-catalysed de-allylation.
- Anbazhagan, Mariappan,Reddy, T. Indrasena,Rajappa, Srinivasachari
-
p. 1623 - 1627
(2007/10/03)
-
- Mild esterification and transesterification of carboxylic acids catalyzed by tetracyanoethylene and dicyanoketene dimethyl acetal
-
A π-acid tetracyanoethylene (TCNE) and its derivative dicyanoketene dimethyl acetal (DCKDMA) were found to catalyze esterification of lauric acid with various types of alcohols. This method was successfully applied to methyl esterification of a variety of carboxylic acids including aromatic, α,β-unsaturated, α-hydroxy, and N-Cbz and N-Boc-protected α-amino acids without racemization at the range from room temperature to 60 °C. TCNE was also found to operate as a catalyst in transeslerification reaction of methyl laurate.
- Masaki, Yukio,Tanaka, Nobuyuki,Miura, Tsuyoshi
-
-
- Asymmetric α-Aminoacid Synthesis using Rearrangement of Allylic Trifluoroacetimidates: Synthesis of Thymine Polyoxin C
-
Improved procedures are reported for the synthesis of chiral trifluoroacetimidates and are applied to complete a total synthesis of thymine polyoxin C.
- Chen, Anqi,,Savage, Ian,Thomas, Eric J.,Wilson, Peter D.
-
p. 6769 - 6772
(2007/10/02)
-
- Peptide-titanium complex as catalyst for asymmetric addition of hydrogen cyanide to aldehyde
-
The complex of titanium ethoxide and an acyclic dipeptide ester whose terminal amino group is modified to a salicylal-type Schiff base catalyzes the asymmetric addition of hydrogen cyanide to aldehydes with high enantioselectivity. In the reaction of benzaldehyde and hydrogen cyanide, (R)-mandelonitrile is obtained with an enantiomeric excess of 90% when N-((2-hydroxy-1-naphthyl)methylene)-(S)-valyl-(S)-tryptophan methyl ester is employed. In place of the dipeptide, the amide derivatives of an amino acid modified by substituted salicylaldehyde, such as N-(3,5-dibromosalicylidene)-(S)-valine piperidide, exhibit an entirely opposite stereoselectivity to yield S-cyanohydrins with optical purities up to 97% ee. This novel peptide-titanium complex, therefore, enables us to afford optically active cyanohydrins of both absolute configurations by using natural S-amino acids as chiral auxiliaries.
- Nitta, Hideaki,Yu, Donghai,Kudo, Masanobu,Mori, Atsunori,Inoue, Shohei
-
p. 7969 - 7975
(2007/10/02)
-
- Syntheses and Reactions of Silyl Carbamates. 1. Chemoselective Transformation of Amino Protecting Groups via tert-Butyldimethylsilyl Carbamates
-
The N-tert-butyldimethylsilyloxycarbonyl group (silyl carbamate) was synthesized from commonly used amino protecting groups such as N-tert-butoxycarbonyl (Boc) and N-benzyloxycarbonyl (Z) by treatment with tert-butyldimethylsilyl trifluoromethanesulfonate/2,6-lutidine and tert-butyldimethylsilane/Pd(OAc)2, respectively.This novel species, upon activation with fluoride ion, reacts with a variety of electrophiles to give N-ester type compounds in high yield.For example, the conversion of N-t-Boc compounds into their corresponding N-Z compounds via a silyl carbamate was accomplished under these mild reaction conditions.
- Sakaitani, Masahiro,Ohfune, Yasufumi
-
p. 870 - 876
(2007/10/02)
-
- Papain catalysed Esterification of N-Protected Amino Acids
-
N-Protected amino acids and amino diacids were converted to their corresponding esters catalysed by immobilized papain with a high concentration of alcohols under mild conditions in a two-phase system.
- Chen, Shui-Tein,Wang, Kung Tsung
-
p. 327 - 328
(2007/10/02)
-
- THE PREPARATION AND REACTIONS OF MIXED ANHYDRIDES OF N-ALKOXYCARBONYLAMINO ACIDS
-
Pure mixed anhydrides R1OCO-Xxx-O-COOR2 (Xxx=NHCHRCO) have been obtained by reaction of N-alkoxycarbonylamino acids R1OCO-Xxx-OH with alkyl chloroformate R2OCOCl (R2=methyl, ethyl, isobutyl, menthyl)
- Chen, Francis M. F.,Benoiton, N. Leo
-
p. 619 - 625
(2007/10/02)
-
- SELECTIVE TRANSFORMATION OF N-t-BUTOXYCARBONYL GROUP INTO N-ALKOXYCARBONYL GROUP via N-CARBOXYLATE ION EQUIVALENT
-
Reaction of a variety of N-t-butoxycarbonyl compounds with t-butyldimethylsilyl trifluoromethanesulfonate afforded the N-t-butyldimethylsilyloxycarbonyl compounds, chemoselectively, which upon treatment with an alkyl or aryl halide provided the corresponding N-alkoxy- or N-aryloxycarbonyl compounds, efficiently.
- Sakaitani, Masahiro,Ohfune, Yasufumi
-
p. 5543 - 5546
(2007/10/02)
-
- Process for the preparation of a carboxylic acid ester
-
An improved and novel process for the preparation of a carboxylic acid ester which comprises reacting a carboxylic acid with an alcohol or a sulfenic acid ester thereof in the presence of a tertiary phosphine and a disulfide of a mercaptoheterocyclic compound containing a nitrogen-carbon double bond with which the disulfide linkage is conjugated.
- -
-
-
