- Unified enantioselective total synthesis of 3,6-dioxygenated diketopiperazine natural products, diatretol and lepistamides A, B and C
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The concise enantioselective total synthesis of Diatretol (1) has been achieved via 9 steps with 30％ yield. The synthetic approach involves stereoselective oxidation and regioselective transacetalization utilizing a folded conformation induced by an intramolecular CH/π interaction. In addition, we have also achieved total synthesis of three diketopiperazine natural products, Lepistamides A (2), B (3) and C (4).
- Takahashi, Shu,Kimishima, Aoi,Hirose, Tomoyasu,Yamada, Takeshi,Sugawara, Akihiro,Shirahata, Tatsuya,Noguchi, Yoshihiko,Iwatsuki, Masato,Hokari, Rei,Ishiyama, Aki,Kobayashi, Yoshinori,Sunazuka, Toshiaki
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- Immobilized Carbodiimide Assisted Flow Combinatorial Protocol to Facilitate Amide Coupling and Lactamization
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Through a screen of over one hundred and 30 permutations of reaction temperatures, solvents, carbodiimide resins, and carbodiimide molar equivalences, in the presence, absence, or combination of diisopropylamine and benzotriazole additives, a convenient and first reported carbodiimide polymer-assisted flow approach to effect amide coupling and lactamization was developed. The protocol entails injecting a single solution (1:9 dimethylformamide: dichloromethane) containing a carboxylic acid and an amine or linear peptide sequence into a continuous stream of dichloromethane. The protocol remained viable in the absence of base, did not require carboxylate preactivation which, and in concert with minimal workup requirements, enabled the isolation of products in high yields. Compared to the utilization of untethered carbodiimide reagents, the flow procedure was also observed to provide a degree of racemization safety.
- Aldrich-Wright, Janice R.,Dankers, Christian,Gordon, Christopher P.,Harman, David G.,Nguyen, Thanh V.,Tadros, Joseph
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supporting information
p. 255 - 267
(2020/06/05)
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- Anti-biofilm and anti-adherence properties of novel cyclic dipeptides against oral pathogens
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Microorganisms embedded in a biofilm are significantly more resistant to antimicrobial agents and the defences of the human immune system, than their planktonic counterpart. Consequently, compounds that can inhibit biofilm formation are of great interest for novel therapeutics. In this study, a screening approach was used to identify novel cyclic dipeptides that have anti-biofilm activity against oral pathogens. Five new active compounds were identified that prevent biofilm formation by the cariogenic bacterium Streptococcus mutans and the pathogenic fungus Candida albicans. These compounds also inhibit the adherence of microorganisms to a hydroxylapatite surface. Further investigations were conducted on these compounds to establish the structure–activity relationship, and it was deduced that the common cleft pattern is required for these molecules to act effectively against biofilms.
- Simon, Ga?lle,Bérubé, Christopher,Voyer, Normand,Grenier, Daniel
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p. 2323 - 2331
(2018/12/11)
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- Interfacial supramolecular biomimetic epoxidation catalysed by cyclic dipeptides
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We synthesised a library of cis- and trans-cyclic dipeptides and evaluated their efficacy as catalysts in the asymmetric Weitz-Scheffer epoxidation of trans-chalcone. A thorough investigation relying on structure-activity studies and computational studies provided insights into the mechanism of the process. Our results revealed some structural features required for efficient conversion and for introduction of chirality into the product. The cyclic dipeptide acts as a catalyst by templating a supramolecular arrangement at the aqueous-organic interface required for efficient transformations to occur. Among all cyclic dipeptides investigated, cyclo(Leu-Leu) was the most efficient supramolecular catalyst.
- Bérubé, Christopher,Barbeau, Xavier,Cardinal, Sébastien,Boudreault, Pierre-Luc,Bouchard, Corinne,Delcey, Nicolas,Lagüe, Patrick,Voyer, Normand
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p. 330 - 349
(2017/03/15)
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- Novel chiral N,N′-dimethyl-1,4-piperazines with metal binding abilities
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With the objective of developing novel chiral ligands, we report an efficient strategy to prepare chiral N,N-dimethyl-1,4-piperazines, six-member heterocyclic molecules that possess metal binding features. We prepared and characterized 18 piperazines, and evaluated their ability to complex different mono- and divalent metals, using a rapid picrate extraction technique. Some newly prepared diamine ligands were used in diethylzinc alkylation of aryl aldehydes. Yields increased significantly in the presence of the diamine ligands, though enantioselectivity was low. The results demonstrate the validity of the approach for preparing and identifying useful chiral diamine ligands.
- Bérubé, Christopher,Cardinal, Sébastien,Boudreault, Pierre-Luc,Barbeau, Xavier,Delcey, Nicolas,Giguère, Martin,Gleeton, Dave,Voyer, Normand
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p. 8077 - 8084
(2015/12/30)
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- Marine natural occurring 2,5-diketopiperazines: Isolation, synthesis and optical properties
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Seven 2,5-diketopiperazines (DKPs) were isolated from the Fijian marine sponge Acanthella cavernosa. NMR and circular dichroism (CD) comparison with synthetic L-L DKPs allowed us to determine unambiguously the L-L absolute configuration of the natural DKPs. This work initiated the setting up of an optical properties database of natural DKPs, including specific rotation and CD.
- Laville, Rmi,Nguyen, Thanh Binh,Moriou, Cline,Petek, Sylvain,Debitus, Ccile,Al-Mourabit, Ali
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p. 1351 - 1366
(2015/03/04)
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- Facile one-step synthesis of 2,5-diketopiperazines
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We report a one-step protocol for the general synthesis of 2,5-diketopiperazines from an Fmoc-protected amino acid and an amino acid ester. The application of the method is highlighted by rapid and efficient preparation of various 2,5-diketopiperazines.
- Sun, Xianyu,Rai, Rachita,Mackerell Jr., Alexander D.,Faden, Alan I.,Xue, Fengtian
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supporting information
p. 1905 - 1908
(2014/03/21)
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- Cyclic dipeptides exhibit potency for scavenging radicals
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Twenty kinds of cyclic dipeptides containing l-leucine were synthesized, and their antioxidant activity against .OH and O2·- was investigated. Compounds possessing polar amino acid residues, such as Asp, Cys, Glu, Lys, Pro, Ser, and Trp, exhibited higher antioxidant activity against .OH than vitamin E. However, only cyclo(l-Cys-l-Leu) scavenged O2·-.
- Furukawa, Tadashi,Akutagawa, Takashi,Funatani, Hitomi,Uchida, Toshikazu,Hotta, Yoshihiro,Niwa, Masatake,Takaya, Yoshiaki
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p. 2002 - 2009
(2012/05/04)
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- Dibutylphosphate (DBP) mediated synthesis of cyclic N,N′- disubstituted urea derivatives from amino esters: A comparative study
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The N,N′-disubstituted urea derivatives such as amino acid hydantoins and dihydrouracil derivatives were prepared starting from natural and unnatural amino acid esters using dibutylphosphate (DBP). During the attempted synthesis of N-heterocycles with larger than six-membered rings containing the N,N′-disubstituted urea functionalities, three unexpected products namely squamolone, N-methyl pyrrolidine-2-one, and diketopiperazine were isolated.
- Agrawal, Sumit K.,Sathe, Manisha,Kaushik, M. P.,Halve, A. K.
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supporting information
p. 5996 - 5999,4
(2020/08/20)
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- Engineered transaminopeptidase, aminolysin-S for catalysis of peptide bond formation to give linear and cyclic dipeptides by one-pot reaction
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Aminopeptidase from Streptomyces thermocyaneoviolaceus NBRC14271 was engineered into transaminopeptidase and used to catalyze an aminolysis reaction to give linear and cyclic dipeptides from cost-effective substrates such as the ester derivatives of amino
- Usuki, Hirokazu,Uesugi, Yoshiko,Arima, Jiro,Yamamoto, Yukihiro,Iwabuchi, Masaki,Hatanaka, Tadashi
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supporting information; experimental part
p. 580 - 582
(2010/05/01)
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- Efficient synthesis of 2,5-diketopiperazines using microwave assisted heating
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In this study a general, efficient and environmentally benign solution phase synthesis of 2,5-diketopiperazines (DKPs) using microwave assisted heating in water is described. A series of 11 structurally different DKPs have been synthesized from dipeptide methyl esters. A range of common laboratory solvents have been tested as well as different reaction times and temperatures. Both classic thermal and microwave assisted heating have been investigated. Microwave assisted heating for 10 min using water as solvent proved, by far, to be the most efficient method of cyclization giving moderate to excellent yields (63-97%) of DKPs. In contrast to other published procedures, this method seems independent of the amino acid sequence.
- Tullberg, Marcus,Gr?tli, Morten,Luthman, Kristina
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p. 7484 - 7491
(2007/10/03)
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- Explanation of bitter taste of venom of ponerine ant, Pachycondyla apicalis
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The venom gland of workers of Pachycondyla (= Neoponera) apicalis (Hymenoptera: Formicidae) contains the bitter-tasting cyclic dipeptide of leucine and phenylalanine [cyclo-leu-phe or 3-benzyl-6-(2-methylpropyl)-2,5-piperazinedione]. The venom also contai
- Lopez, Leopoldo Cruz,Morgan, E. David
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p. 705 - 712
(2007/10/03)
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- Cyclo(dipeptide) as Low-molecular-mass Gelling Agents to Harden Organic Fluids
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Cyclic dipeptides consisting of diverse amino acids can cause physical gelation in a wide variety of organic fluids, including edible oils, glyceryl esters, alcohols and aromatic molecules; the gelation phenomenon is characterized by minimum gel concentration, FTIR spectroscopy, transmission electron microscopy, and X-ray diffraction.
- Hanabusa, Kenji,Matsumoto, Yoshimitsu,Miki, Toru,Koyama, Toshiki,Shirai, Hirofusa
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p. 1401 - 1402
(2007/10/02)
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- Conformational effects in reversed-phase liquid chromatographic separation of diastereomers of cyclic dipeptides
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The capacity factors, k′, of 11 cyclic dipeptides (X-Y) including diastereomers have been determined on an RP-HPLC column in 30% and 50% methanol and 10%, 30%, and 50% acetonitrile solutions. These factors are roughly correlated with hydrophobic parameters, such as octanol-water partition coefficients estimated and k′ values for alcohols. For a pair of diastereomers of cyclic (L-X-L-Phe) and (L-X-D-Phe) derivatives k′LL is larger than k′LD and for cyclic (D-Ala-L-Trp) and (L-Ala-L-Trp) k′LL is smaller than k′DL, particularly in highly aqueous solutions. These elution orders can be well predicted by the holistic molecular surface area approach which takes into account the folded structures of cyclic dipeptides. The present results will be useful for prediction of the log k′ values of larger peptides and the hydrophobicity and related properties of peptides.
- Funasaki, Noriaki,Hada, Sakae,Neya, Saburo
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p. 1861 - 1867
(2007/10/02)
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