13748-90-8Relevant academic research and scientific papers
A post-modification strategy for the synthesis of uniform, hydrophilic/hydrophobic patterned a-hydroxy acid oligomers
Franz, Nadja,Menin, Laure,Klok, Harm-Anton
, p. 5390 - 5405 (2009)
Hydrophilic/hydrophobic patterning is a well-established design strategy to guide secondary structure formation of both natural as well as non-natural oligomers and polymers. This contribution explores the feasibility of a new approach for the synthesis of uniform, sequence-defined, hydrophilic/hydrophobic patterned oligo(α-hydroxy acid)s. The proposed strategy is based on post-modification of a reactive oligoester scaffold composed of an alternating sequence of hydrophobic [(2S)-2-hydroxy-4-methylpentanoic acid] and masked hydrophilic [(2S)-2-hydroxypent-4-enoic acid] a-hydroxy acids. The use of (2S)-2-hydroxypent-4-enoic acid instead of a complex side-chain-protected hydrophilic building block obviates the need for additional protective group chemistry during chain extension. In a subsequent post-modification step, the allyl side chains can be quantitatively modified via free-radical addition of different co-functional thiols to afford hydrophilic/hydrophobic patterned oligoesters. The proposed synthetic strategy provides an interesting alternative to rapidly generate libraries of foldamers with identical chain length and monomer sequence but different side-chain functionalities.
Total synthesis of cyclohexadepsipeptides exumolides A and B
Rahmadani, Agung,Masruhim, Muhammad Amir,Rijai, Laode,Hidayat, Ace Tatang,Supratman, Unang,Maharani, Rani
, (2021)
Exumolides A and B are two cyclodepsipeptides that was previously isolated from marine fungus. Both peptides were synthesized using a combination of solid- and solution-phase method. The linear precursor was synthesized through solid-phase method on 2-chlorotrityl resin with standard Fmoc strategy. The hydroxy acid, (S)-2-hydroxy-4-methylpentanoic acid (Hmp), was prepared from its precursor L-leucine, and attached on the resin with a double-coupling protocol. The depside bond formation that was carried out at the end of the coupling process, was beneficial, particularly, in the blockage of the diketopiperazine formation during Fmoc deprotection. The cyclic product was obtained through HATU-based cyclisation. Exumolides A and B were successfully synthesized with overall yields of 4.12% and 6.39%, respectively.
Enantioselective synthesis of α-hydroxy carboxylic acids: Direct conversion of α-oxocarboxylic acids to enantiomerically enriched α-hydroxy carboxylic acids via neighboring group control
Wang, Zhe,La, Brittany,Fortunak, Joseph M.,Meng, Xian-Jun,Kabalka, George W.
, p. 5501 - 5504 (1998)
α-Oxocarboxylic acids can be reduced to the corresponding α-hydroxy carboxylic acids employing DIP-CI(TM) as a reducing agent. The α-carboxylic substituent exerts a remarkable neighboring group effect on the reduction. The reaction presumably proceeds in an intramolecular fashion through a 'rigid' bicyclic transition state assembly, which produces enantioselectivities approaching 99%.
ACCURATE DETERMINATION OF THE INTRINSIC RACEMIZATION IN CHIRAL SYNTHESIS VIA ENANTIOMER RESOLUTION OF UNDERIVATIZED VICINAL DIOLS
Koppenhoefer, B.,Trettin, U.,Figura, R.,Lin, B.
, p. 5109 - 5110 (1989)
The accurate assessment of the intrinsic racemization (down to 0.01percent), inherent to reactions typically applied in chiral synthesis, demands for (i) a precursor of almost 100percent e.e. (e.g., S-1a, e.e. >=99.99percent), and (ii) a reliable method for the determination of e.e. of the product (e.g., the derivatization-free enantiomer resolution of the vicinal diol 3a by GC on Chirasil-Val).
Synthesis of enantiopure (S)-α-hydroxy carboxanilides from (S)-α-amino acids
Girreser,Noe
, p. 1223 - 1224 (1995)
α-Hydroxy carboxanilides 3 a-c were obtained without racemization in a synthetically simple way starting from the corresponding α-amino acids by diazotization and subsequent treatment of the sodium α-hydroxy carboxylates with anilinium chloride in moderate yields. The enantiopurity of 3a-c was easily determined by 1H NMR spectroscopy of the diastereomeric O,O-acetals 5/6a-c derived from exo-lactol 4.
Cyclodepsipeptides, sesquiterpenoids, and other cytotoxic metabolites from the filamentous fungus Trichothecium sp. (MSX 51320)
Sy-Cordero, Arlene A.,Graf, Tyler N.,Adcock, Audrey F.,Kroll, David J.,Shen, Qi,Swanson, Steven M.,Wani, Mansukh C.,Pearce, Cedric J.,Oberlies, Nicholas H.
, p. 2137 - 2142 (2011)
Two new cyclodepsipeptides (1 and 2), two new sesquiterpenoids (3 and 4), and the known compounds guangomide A (5), roseotoxin S, and three simple trichothecenes were isolated from the cytotoxic organic extract of a terrestrial filamentous fungus, Trichothecium sp. The structures were determined using NMR spectroscopy and mass spectrometry. Absolute configurations of the cyclodepsipeptides were established by employing chiral HPLC, while the relative configurations of 3 and 4 were determined via NOESY data. The isolation of guangomide A was of particular interest, since it was reported previously from a marine-derived fungus.
A small synthetic molecule forms chloride channels to mediate chloride transport across cell membranes
Li, Xiang,Shen, Bing,Yao, Xiao-Qiang,Yang, Dan
, p. 7264 - 7265 (2007)
Synthetic ion channels that mimic the functions of natural ion channels are of great interest in chemistry, biochemistry, biology, and materials science. In this paper, we present a novel small synthetic molecule that self-assembles to form chloride channels in lipid bilayers. This compound is the smallest molecule known to form potent synthetic chloride ion channels. It can also partition into plasma membranes of living cells and therein increase anion permeability. This compound has the potential to become a novel lead compound for the treatment of human diseases associated with Cl- channel dysfunctions. Copyright
Biocontrolled formal inversion or retention of L -α-amino acids to enantiopure (R)- or (S)-hydroxyacids
Busto, Eduardo,Grischek, Barbara,Kroutil, Wolfgang,Richter, Nina
, p. 11225 - 11228,4 (2014)
Natural L-α-amino acids and L-norleucine were transformed to the corresponding α-hydroxy acids by formal biocatalytic inversion or retention of absolute configuration. The one-pot transformation was achieved by a concurrent oxidation reduction cascade in aqueous media. A representative panel of enantiopure (R)- and (S)-2-hydroxy acids possessing aliphatic, aromatic and heteroaromatic moieties were isolated in high yield (67-85 %) and enantiopure form (>99 % ee) without requiring chromatographic purification.
Mo–Catalyzed One-Pot Synthesis of N-Polyheterocycles from Nitroarenes and Glycols with Recycling of the Waste Reduction Byproduct. Substituent-Tuned Photophysical Properties
Hernández-Ruiz, Raquel,Rubio-Presa, Rubén,Suárez-Pantiga, Samuel,Pedrosa, María R.,Fernández-Rodríguez, Manuel A.,Tapia, M. José,Sanz, Roberto
supporting information, p. 13613 - 13623 (2021/08/23)
A catalytic domino reduction–imine formation–intramolecular cyclization–oxidation for the general synthesis of a wide variety of biologically relevant N-polyheterocycles, such as quinoxaline- and quinoline-fused derivatives, and phenanthridines, is reported. A simple, easily available, and environmentally friendly dioxomolybdenum(VI) complex has proven to be a highly efficient and versatile catalyst for transforming a broad range of starting nitroarenes involving several redox processes. Not only is this a sustainable, step-economical as well as air- and moisture-tolerant method, but also it is worth highlighting that the waste byproduct generated in the first step of the sequence is recycled and incorporated in the final target molecule, improving the overall synthetic efficiency. Moreover, selected indoloquinoxalines have been photophysically characterized in cyclohexane and toluene with exceptional fluorescence quantum yields above 0.7 for the alkyl derivatives.
Total Synthesis of the Natural Herbicide MBH-001 and Analogues
Barber, David M.,D?ller, Uwe,Dietrich, Hansj?rg,Hoffmann, Michael G.,Kocakaya, Tamer,Kuhn, Birgit,Maier, Martin E.,Morkunas, Marius,Schmutzler, Dirk,Schnatterer, Stefan
, p. 2271 - 2290 (2020/04/23)
The first total synthesis of the natural herbicide MBH-001 (1) is reported. Structurally it is a 2-methyloxazol-5(2H)-one with a (1-hydroxyethyl) substituent at the 2-position. By relying on cyclic nitrones, a flexible route to MBH-001 and relevant analogues was developed. Key steps include the reaction of a 2-hydroxyimino ester with an aldehyde to form a 5-oxo-2,5-dihydrooxazole 3-oxide. In an aldol-type reaction, the anion of these cyclic nitrones reacted with an aldehyde at the 2-position. A final reduction of the nitrone to the corresponding imine using zinc led to the target compounds. The cyclic nitrones are also accessible by reacting an α-keto acid with an oxime. These two versatile synthetic routes enabled us to prepare the first MBH-001 analogues for structure activity relationship analysis of the herbicidal efficacy. Thus, furthering our aim of developing new herbicides to tackle the ever-growing problem of weed resistance.
