77697-15-5Relevant articles and documents
Svetamycins A-G, Unusual Piperazic Acid-Containing Peptides from Streptomyces sp.
Dardi?, Denis,Lauro, Gianluigi,Bifulco, Giuseppe,Laboudie, Patricia,Sakhaii, Peyman,Bauer, Armin,Vilcinskas, Andreas,Hammann, Peter E.,Plaza, Alberto
, p. 6032 - 6043 (2017/06/23)
Seven new halogenated peptides termed svetamycins A-G (1-7) have been isolated from laboratory cultures of a Streptomyces sp. Svetamycins A-D, F, and G are cyclic depsipeptides, whereas svetamycin E is a linear analogue of svetamycin C. Their structures were determined using extensive spectroscopic analysis, and their stereochemical configuration was established by a combination of NMR data, quantum mechanical calculations, and chemical derivatizations. Svetamycins are characterized by the presence of a hydroxyl acetic acid and five amino acids including a rare 4,5-dihydroxy-2,3,4,5-tetrahydropyridazine-3-carboxylic acid, a γ-halogenated piperazic acid, and a novel δ-methylated piperazic acid in svetamycins B-C, E, and G. Moreover, isotope-labeled substrate feeding experiments demonstrated ornithine as the precursor of piperazic acid and that methylation at the δ position of the piperazyl scaffold is S-adenosyl-l-methionine (SAM)-dependent. Svetamycin G, the most potent antimicrobial of this suite of compounds, inhibited the growth of Mycobacterium smegmatis with an MIC80 value of 2 μg/mL.
Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy
Liu, Huili,Zheng, Kuan,Lu, Xiang,Wang, Xiaoxia,Hong, Ran
supporting information, p. 983 - 990 (2013/07/19)
A "stop-and-flow" strategy was developed for the chemoselective dioxygenation of alkenes with a PIFA-initiated cyclization. This method is conceived for the desymmetrization of seco-diene, and a series of substituted 5-hydroxymethyl-γ-lactones were constructed after hydrolysis. This strategy also differentiates terminally substituted alkenes and constitutes a potentially novel synthetic approach for the efficient synthesis toward velbanamine.
Practical synthesis of C1-8 fragment of autolytimycin via a chelation-controlled diastereoselective addition of diisopropenylzinc to α-methoxy aldehyde
Yang, Fan,Feng, Liang,Wang, Nengzhong,Liu, Xuge,Li, Jun,Shen, Yuehai
, p. 9463 - 9468 (2013/10/08)
The C1-8 fragment of autolytimycin was synthesized via a reliable 10-step route capable of delivering 41% overall yield at multi-gram scale. As a key step, a chelation-controlled isopropenylation of α-oxygenated aldehydes was established with a reagent combination of diisopropenylzinc, magnesium halide, and a dichloromethane/toluene mixed solvent. Cram-chelate isopropenylation products dominated for aldehydes with a small α-substituents, such as -OMe and -OBn groups, while the Felkin product could be obtained with a bulky -OTBS group.
First total synthesis of Debilisone C
Saikia, Bishwajit,Joymati Devi, Thongam,Barua, Nabin C.
, p. 905 - 913 (2013/03/14)
Total synthesis of Debilisone C, a lactone containing conjugated endiyne has been achieved. The adopted strategy involves the stereoselective construction of the five membered lactone ring and the C20 endiyne chain followed by regioselective coupling of both the parts. The lactone was obtained from the oxidative cleavage of the hydroxy olefin which was derived from the benzyl protected S-epichlorohydrine by regioselective epoxide opening with allyl trimethyl silane in presence of a Lewis acid at -78 °C. Takai olefination, Pd0/Ag1 catalyzed cross-coupling reaction and selective substitution of trimethylsilyl groups were successfully utilized to establish the C20 polyyne chain. The final coupling of both the parts have been carried out by alkyl coupling using LDA in THF-DMPU (1 : 1).
Pyrene intercalating nucleic acids with a carbon linker
stergaard, Michael E.,Wamberg, Michael C.,Pedersen, Erik B.
scheme or table, p. 210 - 226 (2012/04/18)
We have synthesized a carbon linker analogue of INA (oligonucleotides containing insertions of 1-O-(1-pyrenylmethyl)glycerol). Thermal stability studies showed an increase in melting temperature in favor of the carbon linker analogue. We also synthesized a carbon linker analogue with two pyrenes geminally attached. Fluorescence studies of this intercalating nucleic acid with the pyrene moieties inserted as a bulge showed formation of an excimer band. When a mismatch was introduced at the site of the intercalator, an excimer band was formed for the destabilized duplexes whereas an exciplex band was observed when the stability of the duplex was retained. Copyright Taylor and Francis Group, LLC.
Cyclopropenium-activated cyclodehydration of diols
Kelly, Brendan D.,Lambert, Tristan H.
supporting information; experimental part, p. 740 - 743 (2011/05/04)
The dehydrative cyclization of diols to cyclic ethers via cyclopropenium activation is described. Using 2,3-diphenylcyclopropene and methanesulfonic anhydride, a series of 1,4-and 1,5-diols are rapidly cyclized to furnish tetrahydrofurans and tetrahydropyrans in high yield. Eleven total substrates are shown, including a gram scale cyclization of a diterpene derivative.
Drug delivery by an enzyme-mediated cyclization of a lipid prodrug with unique bilayer-formation properties
Linderoth, Lars,Peters, Gnther H.,Madsen, Robert,Andresen, Thomas L.
supporting information; experimental part, p. 1823 - 1826 (2009/09/07)
Special delivery: Liposomal drug-delivery systems in which prodrugs are activated specifically by disease-associated enzymes have great potential for the treatment of severe diseases, such as cancer. A new type of phospholipid-based prodrug has the ability to form stable small unilamellar vesicles (see picture). Activation of the prodrug vesicles by the enzyme sPLA2 initiates a cyclization reaction, which leads to the release of the drug.
Efficient chirality transfer in the Sml2-mediated cyclization of aldehydo β-alkoxyvinyl sulfoxides: Asymmetric synthesis of 3-hydroxyoxanes
Jung, Jae Hoon,Kim, Yong Wook,Kim, Min Ah,Choi, Soo Young,Chung, Young Keun,Kim, Tae-Rae,Shin, Seokmin,Lee, Eun
, p. 3225 - 3228 (2008/02/11)
Stereoselective syntheses of 3-hydroxyoxanes were achieved via efficient chirality transfer in the Sml2-mediated cyclization reactions of aldehydo β-alkoxyvinyl sulfoxides.
Benzyl N-phenyl-2,2,2-trifluoroacetimidate: A new and stable reagent for O-benzylation
Okada, Yasunori,Ohtsu, Mamiko,Bando, Masafumi,Yamada, Hidetoshi
, p. 992 - 993 (2008/02/10)
A new O-benzylation reagent, benzyl N-phenyl-2,2,2-trifluoroacetimidate, has been developed. It even reacts with sterically hindered alcohols and base-sensitive hydroxy esters to afford the corresponding benzyl ethers catalyzed by TMSOTf in 1,4-dioxane. This reagent was more stable than benzyl 2,2,2-trichloroacetimidate, a known benzylation reagent. Copyright
Synthesis of γ- and δ-lactones from alkynols
Tiecco, Marcello,Testaferri, Lorenzo,Temperini, Andrea,Terlizzi, Raffaella,Bagnoli, Luana,Marini, Francesca,Santi, Claudio
, p. 587 - 590 (2007/10/03)
The reaction of alkynyl phenyl selenides with p-toluene-sulfonic acid gives rise to a proton-induced ring-closure reaction affording γ- and δ-lactones. Georg Thieme Verlag Stuttgart.
