1
|
Protocol for Sonogashira coupling of alkynes and aryl halides via nickel catalysis. STAR Protoc 2024; 5:102900. [PMID: 38367230 PMCID: PMC10879785 DOI: 10.1016/j.xpro.2024.102900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/29/2023] [Accepted: 02/02/2024] [Indexed: 02/19/2024] Open
Abstract
Alkynes are widely present in natural products and pharmaceutical compounds. Here, we present a protocol for nickel-catalyzed cross-coupling of terminal alkynes with aryl iodides or bromides for constructing a C(sp2)-C(sp) bond. We describe steps for reagent preparation, reaction setup, purification process, and product characterization. We also detail procedures for obtaining a single crystal of 6-(phenylethynyl)-1-(phenylsulfonyl)-1H-indole (3b). The application of this protocol is limited to aryl bromide and iodide. For complete details on the use and execution of this protocol, please refer to Chen et al.1.
Collapse
|
2
|
Development of an Allenyne-Alkyne [4+2] Cycloaddition and its Application to Total Synthesis of Selaginpulvilin A. Chemistry 2022; 28:e202202015. [PMID: 35771213 PMCID: PMC9805236 DOI: 10.1002/chem.202202015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Indexed: 01/09/2023]
Abstract
A new [4+2] cycloaddition of allenyne-alkyne is developed. The reaction is believed to proceed with forming an α,3-dehydrotoluene intermediate. This species behaves as a σπ-diradical to react with a hydrogen atom donor, whereas it displays a zwitterionic reactivity toward weak nucleophiles. The efficiency of trapping α,3-dehydrotoluene depends not only on its substituents but also the trapping agents. Notable features of the reaction are the activating role of the extra alkyne of the 1,3-diyne that reacts with the allenyne moiety and the opposite mode of trapping with oxygen and nitrogen nucleophiles. Oxygen nucleophiles result in the oxygen-end incorporation at the benzylic position of the α,3-dehydrotoluene, whereas with amine nucleophiles the nitrogen-end is incorporated into the aromatic core. Relying on the allenyne-alkyne cycloaddition as an enabling strategy, a concise total synthesis of phosphodiesterase-4 inhibitory selaginpulvilin A is realized.
Collapse
|
3
|
In-Cell Generation of Anticancer Phenanthridine Through Bioorthogonal Cyclization in Antitumor Prodrug Development. Angew Chem Int Ed Engl 2021; 60:24043-24047. [PMID: 34487611 DOI: 10.1002/anie.202110041] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/26/2021] [Indexed: 01/06/2023]
Abstract
Pharmacological inactivation of antitumor drugs toward healthy cells is a critical factor in prodrug development. Typically, pharmaceutical chemists graft temporary moieties to existing antitumor drugs to reduce their pharmacological activity. Here, we report a platform able to generate the cytotoxic agent by intramolecular cyclization. Using phenanthridines as cytotoxic model compounds, we designed ring-opened biaryl precursors that generated the phenanthridines through bioorthogonal irreversible imination. This reaction was triggered by reactive oxygen species, commonly overproduced in cancer cells, able to convert a vinyl boronate ester function into a ketone that subsequently reacted with a pendant aniline. An inactive precursor was shown to engender a cytotoxic phenanthridine against KB cancer cells. Moreover, the kinetic of cyclization of this prodrug was extremely rapid inside living cells of KB cancer spheroids so as to circumvent drug action.
Collapse
|
4
|
In‐Cell Generation of Anticancer Phenanthridine Through Bioorthogonal Cyclization in Antitumor Prodrug Development. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
5
|
|
6
|
Temporary ether protecting groups at the anomeric center in complex carbohydrate synthesis. Adv Carbohydr Chem Biochem 2020; 77:1-69. [PMID: 33004110 DOI: 10.1016/bs.accb.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis of a carbohydrate building block usually starts with introduction of a temporary protecting group at the anomeric center and ends with its selective cleavage for further transformation. Thus, the choice of the anomeric temporary protecting group must be carefully considered because it should retain intact during the whole synthetic manipulation, and it should be chemoselectively removable without affecting other functional groups at a late stage in the synthesis. Etherate groups are the most widely used temporary protecting groups at the anomeric center, generally including allyl ethers, MP (p-methoxyphenyl) ethers, benzyl ethers, PMB (p-methoxybenzyl) eithers, and silyl ethers. This chapter provides a comprehensive review on their formation, cleavage, and applications in the synthesis of complex carbohydrates.
Collapse
|
7
|
Diastereoselective Synthesis of an Advanced Intermediate of Thapsigargin and Other 6,12-Guaianolides Using a RCEYM Strategy. Org Lett 2018; 20:2176-2180. [PMID: 29616815 DOI: 10.1021/acs.orglett.8b00456] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A new and flexible approach toward the synthesis of 6,12-guaianolide anticancer drugs such as trilobolides or thapsigargin has been developed that could be applied to the preparation of analogues with a modified ring system. The synthesis starts from commercial 2-methylcyclopentane-1,3-dione, only relying on diastereoselective reactions for the construction of the stereogenic centers at C1, C3, C6, and C10 and features a high-yielding ring-closing enyne metathesis (RCEYM) step for the formation of the [5,7] bicyclic core.
Collapse
|
8
|
Total synthesis of the antibiotic 4-hydroxycyclopent-2-en-1-one acrylate derivative EA-2801. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.04.086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
Silyl-protective groups influencing the reactivity and selectivity in glycosylations. Beilstein J Org Chem 2017; 13:93-105. [PMID: 28228850 PMCID: PMC5301963 DOI: 10.3762/bjoc.13.12] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/23/2016] [Indexed: 11/26/2022] Open
Abstract
Silyl groups such as TBDPS, TBDMS, TIPS or TMS are well-known and widely used alcohol protective groups in organic chemistry. Cyclic silylene protective groups are also becoming increasingly popular. In carbohydrate chemistry silyl protective groups have frequently been used primarily as an orthogonal protective group to the more commonly used acyl and benzyl protective groups. However, silyl protective groups have significantly different electronic and steric requirements than acyl and alkyl protective groups, which particularly becomes important when two or more neighboring alcohols are silyl protected. Within the last decade polysilylated glycosyl donors have been found to have unusual properties such as high (or low) reactivity or high stereoselectivity. This mini review will summarize these findings.
Collapse
|
10
|
|
11
|
Streamlined Total Synthesis of Uncialamycin and Its Application to the Synthesis of Designed Analogues for Biological Investigations. J Am Chem Soc 2016; 138:8235-46. [DOI: 10.1021/jacs.6b04339] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
12
|
|
13
|
Making a Long Journey Short: Alkyne Functionalization of Natural Product Scaffolds. Chemistry 2016; 22:4666-78. [PMID: 26752308 DOI: 10.1002/chem.201504419] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 01/09/2023]
Abstract
Biological selection makes natural products promising scaffolds for drug development and the ever growing number of newly identified, structurally diverse molecules helps to fill the gaps in chemical space. Elucidating the function of a small molecule, such as identifying its protein binding partners, its on- and off-targets, is becoming increasingly important. Activity- and affinity-based protein profiling are modern strategies to acquire such molecular-level information. Introduction of a molecular handle (azide, alkyne, biotin) can shed light on the mode of action of small molecules. This Concept article covers central points on synthetic methodology for integrating a terminal alkyne into a molecule of interest.
Collapse
|
14
|
Total synthesis and related studies of large, strained, and bioactive natural products. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2016; 92:290-329. [PMID: 27725470 PMCID: PMC5243947 DOI: 10.2183/pjab.92.290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Our chemical syntheses and related scientific investigations of natural products with complex architectures and powerful biological activities are described, focusing on the very large 3 nm-long polycyclic ethers called the ciguatoxins, highly strained and labile chromoprotein antitumor antibiotics featuring nine-membered enediyne cores, and extremely potent anthelmintic macrolides called the avermectins.
Collapse
|
15
|
Abstract
We highlight the total syntheses of 33 complex natural O-glycosides, with a particular focus on the O-glycosylation methods that enable the connection of the saccharides and aglycones.
Collapse
|
16
|
Control Strategy for the Manufacture of Brivanib Alaninate, a Novel Pyrrolotriazine VEGFR/FGFR Inhibitor. Org Process Res Dev 2014. [DOI: 10.1021/op500126u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
17
|
Abstract
Protected 4-hydroxycyclopentenones (4-HCPs) constitute an important class of intermediates in chemical synthesis. A route to this class of compound has been developed. Key steps include Noyori reduction (which establishes the stereochemistry of the product), ring-closing metathesis, and simple functional group conversions to provide a set of substituted 4-HCPs in either enantiomeric form.
Collapse
|
18
|
Abstract
An asymmetric total synthesis of the aminocyclopentitol pactamycin is described. The title compound is delivered in 15 steps from 2,4-pentanedione. Critical to this approach was the exploitation of a complex symmetry-breaking reduction strategy to assemble the C1, C2, and C7 relative stereochemistry within the first four steps of the synthesis. Multiple iterations of this reduction strategy are described, and a thorough analysis of stereochemical outcomes is detailed. In the final case, an asymmetric Mannich reaction was developed to install a protected amine directly at the C2 position. Symmetry-breaking reduction of this material gave way to a remarkable series of stereochemical outcomes leading to the title compound without recourse to nonstrategic downstream manipulations. This synthesis is immediately accommodating to the preparation of structural analogs.
Collapse
|
19
|
|
20
|
Abstract
This article describes synthetic studies that culminated in the first total synthesis of the Lycopodium alkaloid sieboldine A. During this study, a number of pinacol-terminated cationic cyclizations were examined to form the cis-hydrindanone core of sieboldine A. Of these, a mild Au(I)-promoted 1,6-enyne cyclization that was terminated by a semipinacol rearrangement proved to be most efficient. Fashioning the unprecedented N-hydroxyazacyclononane ring embedded within the bicyclo[5.2.1]decane-N,O-acetal moiety of sieboldine A was a formidable challenge. Ultimately, the enantioselective total synthesis of (+)-sieboldine A was completed by forming this ring in good yield by cyclization of a protected-hydroxylamine thioglycoside precursor.
Collapse
|
21
|
Allylic Substitution on Cyclopentene and -hexene Rings with Alkynylcopper Reagents. Org Lett 2011; 13:6252-5. [DOI: 10.1021/ol202711k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
22
|
Asymmetric synthesis of trans-4,5-dioxygenated cyclopentenone derivatives by organocatalyzed rearrangement of pyranones and enzymatic dynamic kinetic resolution. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.02.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
23
|
|
24
|
Probing the Biology of Natural Products: Molecular Editing by Diverted Total Synthesis. Angew Chem Int Ed Engl 2010; 49:9592-628. [DOI: 10.1002/anie.200904761] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
25
|
Untersuchung der Biologie von Naturstoffen: systematische Strukturvariation durch umgelenkte Totalsynthese. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200904761] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
26
|
|
27
|
Use of N-methylformamide as a solvent in indium-promoted Barbier reactions en route to enediyne and epoxy diyne formation: comparison of rate and stereoselectivity in C-C bond-forming reactions with water. J Org Chem 2010; 74:5861-70. [PMID: 19634900 PMCID: PMC2976581 DOI: 10.1021/jo900763u] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Indium-promoted coupling reactions between propargyl aldehydes (1) and α-chloropropargylphenyl sulfide are reported. Although water has been shown to accelerate indium metal promoted reactions, the reverse pattern was observed in this series. Use of N-methylformamide (NMF), which has not previously been a solvent known for use in indium-promoted reactions, afforded an acceleration of these Barbier-style reactions compared to water. Indium-promoted reactions in this study also showed excellent regiocontrol and good stereocontrol, allowing for easy entry into the formation of epoxydiyne and enediyne skeletal structures. This paper also describes use of the Barbier Coupled product (2) as a new, and easy, entry into the formation of enediyne and epoxydiyne skeletal structures.
Collapse
|
28
|
|
29
|
An Efficient Synthesis of a Cyclic Ether Key Intermediate for 9-Membered Masked Enediyne Using an Automated Synthesizer. Org Process Res Dev 2009. [DOI: 10.1021/op9002455] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
30
|
Asymmetric Organocatalytic Formal Alkynylation and Alkenylation of α,β-Unsaturated Aldehydes. J Am Chem Soc 2009; 131:10581-6. [DOI: 10.1021/ja903920j] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
31
|
Efficient Synthesis of (+)-MK7607 and its C-1 Epimer via the Stereoselective Transposition of a Tertiary Allylic Alcohol. Org Lett 2009; 11:2583-6. [DOI: 10.1021/ol9008987] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
32
|
Designed DNA probes from the neocarzinostatin family: impact of glycosyl linkage stereochemistry on bulge base binding. Bioorg Med Chem 2009; 17:2428-32. [PMID: 19243952 DOI: 10.1016/j.bmc.2009.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 02/02/2009] [Accepted: 02/03/2009] [Indexed: 10/21/2022]
Abstract
Bulged sites in DNA and RNA have become targets for rational drug design due to their suspected involvement in a number of key biomolecular processes. A lead compound, derived from the enediyne natural product NCS-chrom has been used to inform chemical synthesis of a family of designed probes of DNA bulges, one of which shows 80 nM affinity for a two base bulged target. Key contributors to binding of these spirocyclic compounds have been studied in order to correlate affinity and specificity with structural features. Herein, we demonstrate that the glycosyl linkage stereochemistry of the pendant aminofucosyl group plays a pivotal role in binding, and coupled with insight obtained with various bulged targets, will allow rational design of second generation ligands.
Collapse
|
33
|
Abstract
The last one hundred years have witnessed a dramatic increase in the power and reach of total synthesis. The pantheon of accomplishments in the field includes the total synthesis of molecules of unimaginable beauty and diversity such as the four discussed in this article: endiandric acids (1982), calicheamicin gamma(1)(I) (1992), Taxol (1994), and brevetoxin B (1995). Chosen from the collection of the molecules synthesized in the author's laboratories, these structures are but a small fraction of the myriad constructed in laboratories around the world over the last century. Their stories, and the background on which they were based, should serve to trace the evolution of the art of chemical synthesis to its present sharp condition, an emergence that occurred as a result of new theories and mechanistic insights, new reactions, new reagents and catalysts, and new synthetic technologies and strategies. Indeed, the advent of chemical synthesis as a whole must be considered as one of the most influential developments of the twentieth century in terms of its impact on society.
Collapse
|
34
|
Functionalised butanediacetal-protected 1,2-diols as suitable partners for Pd-catalysed cross-coupling reactions. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
35
|
Synthesis of the Bicyclo[7.3.0]dodecadiyne Core of the Maduropeptin Chromophore. Chem Asian J 2008; 3:447-53. [DOI: 10.1002/asia.200700310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
36
|
Alkynylation of chiral aldehydes: alkoxy-, amino-, and thio-substituted aldehydes. Chem Rev 2007; 106:2355-403. [PMID: 16771453 DOI: 10.1021/cr0509915] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
37
|
Protein–Small Molecule Interactions in Neocarzinostatin, the Prototypical Enediyne Chromoprotein Antibiotic. Chembiochem 2007; 8:704-17. [PMID: 17451164 DOI: 10.1002/cbic.200600534] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The enediyne chromoproteins are a class of potent antitumour antibiotics comprising a 1:1 complex of a protein and a noncovalently bound chromophore. The protein is required to protect and transport the highly labile chromophore, which acts as the cytotoxic component by reacting with DNA leading to strand cleavage. A derivative of the best-studied member of this class, neocarzinostatin (NCS), is currently in use as a chemotherapeutic in Japan. The application of the chromoproteins as therapeutics along with their unique mode of action has prompted widespread interest in this area. Notable developments include the discovery of non-natural ligands for the apoproteins and the observation that multiple binding modes are available for these ligands in the binding site. Mutation studies on the apoproteins have revealed much about their stability and variability, and the application of an in vitro evolution method has conferred new binding specificity for unrelated ligands. These investigations hold great promise for the application of the apoproteins for drug-delivery, transport and stabilisation systems.
Collapse
|
38
|
Molecular probes of DNA bulges: Functional assay and spectroscopic analysis. Bioorg Med Chem 2007; 15:784-90. [PMID: 17085052 DOI: 10.1016/j.bmc.2006.10.052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 10/22/2006] [Accepted: 10/23/2006] [Indexed: 11/30/2022]
Abstract
Bulged structures in DNA and RNA have been linked to biomolecular processes involved in numerous diseases, thus probes with affinity for these nucleic acid targets would be of considerable utility to chemical biologists. Herein, we report guided chemical synthesis of small molecules capable of binding to DNA bulges by virtue of their unique (spirocyclic) geometry. The agents, modeled on a natural product congener, show pronounced selectivity for specific bulged motifs and are able to enhance slipped DNA synthesis, a hallmark functional assay of bulge binding. Significantly, bulge-agent complexes demonstrate characteristic fluorescent signatures depending on bulge and flanking sequence in the oligo. It is anticipated that these signature patterns can be harnessed as molecular probes of bulged hotspots in DNA and RNA.
Collapse
|
39
|
Synthetic strategies to epoxydiynes and a key synthon of the neocarzinostatin chromophore. Org Biomol Chem 2007; 5:3703-12. [DOI: 10.1039/b711196g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
40
|
Synthesis and NMR binding study of a chiral spirocyclic helical analogue of a natural DNA bulge binder. Org Lett 2006; 6:4833-6. [PMID: 15606078 DOI: 10.1021/ol048152c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
[reaction: see text] Synthesis of chiral spirocyclic helical compounds which mimic the molecular architecture of the potent DNA bulge binder obtained from the antitumor agent NCS-chrom has been accomplished. Structural analysis of the compounds by CD and NMR is presented. NMR titration study indicates binding of P,alpha-helimer (1d) at a two-base bulge site in a DNA oligomer, providing insight to the design of agents as specific probes of a bulged structure in nucleic acids.
Collapse
|
41
|
Direct Synthesis of Esters and Amides from Unprotected Hydroxyaromatic and -aliphatic Carboxylic Acids. J Org Chem 2006; 71:3364-74. [PMID: 16626115 DOI: 10.1021/jo052293q] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A facile method for the activation of hydroxy-substituted carboxylic acids using benzotriazole chemistry without prior protection of the hydroxy substituents is presented. The N-acylbenzotriazole intermediates 2a-g, 6a-d, and 9a-c have been used for high-yielding synthesis of both aliphatic (3a-l) and aromatic (7a-h, 10a-f) hydroxy carboxamides. High yields of aromatic hydroxy esters 12a-h and 13a-i were obtained using either neat alcohols in neutral microwave conditions or nucleophilic alkoxides and the intermediate N-(arylacyl)benzotriazoles. Moderate yields were obtained in the case of aliphatic hydroxy esters 11a,b and thiolesters 11e-g from the intermediates 2a-c.
Collapse
|
42
|
Exploring the Chemistry and Biology of Antitumor Enediyne Chromoprotein C-1027. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2006. [DOI: 10.1246/bcsj.79.501] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
43
|
The Application of [γ-(Silyloxy)allylidene]ditin to the Efficient Synthesis of the Chromophore of the Neocarzinostatin Dihydroxycyclopentene-Based Dienediyne Core. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500353] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
44
|
|
45
|
Synthesis of the C-1027 Chromophore Framework through Atropselective Macrolactonization. Angew Chem Int Ed Engl 2004; 43:6500-5. [PMID: 15578773 DOI: 10.1002/anie.200461428] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
46
|
Synthesis of the C-1027 Chromophore Framework through Atropselective Macrolactonization. Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200461428] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
47
|
|
48
|
|
49
|
|
50
|
Convergent approach to the maduropeptin chromophore: aryl ether formation of (R)-3-aryl-3-hydroxypropanamide and cyclization of macrolactam. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.02.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|