- Stereostructure Clarifying Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone B. A Highly Acid-Labile N-Protecting Group for Amides ?
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The 5S, 8′R, and 10′R configurations of militarinone B (3), which is a natural product from Paecilomyces militaris, should equal those in its biosynthetic precursor, militarinone C. The configuration at C-1′ emerged from syntheses of the militarinone B candidates 1′′S- and 1′′R-(5S,8′R,10′R)-3 from the building blocks 9, 11, 14, and 15a while introducing TMB as a more acid-labile N-protecting group for β-ketoamides than DMB. Comparisons of 1′′S- and 1′′R-(5S,8′R,10′R)-3 with natural militarinone B (3; reisolated from Nature) revealed identity versus distinctness.
- Drescher, Christian,Brückner, Reinhard
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supporting information
p. 6194 - 6199
(2021/08/18)
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- MACROCYCLIC COMPOUNDS AS PROTEASOME INHIBITORS
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The compounds of the present invention are represented by the following compounds having Formula I and Formula (I'): where the substituents R1, R2, R2', R3, R4, R5, R', R", X, Y, and Z are as defined herein and where the substituents R1, R2, R3, R4, R5, R', R", X, Y, and Z are as defined herein. These compounds are used in the treatment of bacterial infections, parasite infections, fungal infections, cancer, immunologic disorders, autoimmune disorders, neurodegenerative diseases and disorders, inflammatory disorders, or muscular dystrophy or for providing immunosuppression for transplanted organs or tissues.
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Paragraph 0560
(2019/05/02)
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- Stereoselective ring contraction of 2,5-diketopiperazines: An innovative approach to the synthesis of promising bioactive 5-membered scaffolds
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Ring contraction of 2,5-diketopiperazines by TRAL-alkylation led us to the stereoselective synthesis of original pyrrolidine-2,4-diones, a novel series of promising molecules with moderate anti-proliferative activity on breast cancer cells.
- Coursindel, Thibault,Restouin, Audrey,Dewynter, Georges,Martinez, Jean,Collette, Yves,Parrot, Isabelle
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experimental part
p. 210 - 217
(2010/10/01)
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- Microwave-assisted synthesis of the Sch?llkopf chiral auxiliaries: (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine
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A practical and efficient methodology for the laboratory scale preparation of Sch?llkopf's bis-lactim ether chiral auxiliaries (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine has been developed. The key step is the preparation of the 2,5-diketopiperazine derivative by microwave-assisted heating in water. The protocol avoids reactions at low temperature and the use of high boiling solvents. Only inexpensive and readily available starting materials are required. The bis-lactim ethers were produced in high yields on a multigram scale.
- Carlsson, Anna-Carin,Jam, Fariba,Tullberg, Marcus,Pilotti, ?ke,Ioannidis, Panos,Luthman, Kristina,Gr?tli, Morten
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p. 5199 - 5201
(2007/10/03)
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- An improved large scale synthesis of the Schoellkopf chiral auxiliaries: (2R)-and (2S)-2,5-Dihydro-3,6-dimethoxy-2-isopropylpyrazine
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Syntheses of the Schoellkopf chiral auxiliaries have been carried out on large scale in high overall yields from D- and L-valine. This method avoids the use of highly toxic phosgene or triphosgene, low-temperature reactions, and unstable intermediates.
- Chen, Jianxie,Corbin, Scott P.,Holman, Nicholas J.
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p. 185 - 187
(2012/12/24)
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- Synthesis of optically active ring-A substituted tryptophans as IDO inhibitors
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The first synthesis of optically active 7-methoxy-d-tryptophan as well as other ring-A substituted tryptophans is described.
- Li, Xiaoyan,Yin, Wenyuan,Sarma, P.V.V. Srirama,Zhou, Hao,Jun Ma,Cook, James M.
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p. 8569 - 8573
(2007/10/03)
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- A Strategy Towards the Stereoselective Synthesis of 5-Hydroxylysine
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A stereoselective synthesis of 5-hydroxylysine is described in which the α-stereogenic centre is generated by a Schoellkopf amino acid synthesis, and the ethanolamine structure is obtained via Sharpless aminohydroxylation from an olefin moiety. The reactions and their selectivities are studied.
- Loehr, Birgit,Orlich, Simone,Kunz, Horst
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p. 1139 - 1141
(2007/10/03)
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- Stereospecific Synthesis of α-Deuteriated α-Amino Acids: Regiospecific Deuteriation of Chiral 3-Isopropyl-2,5-dimethoxy-3,6-dihydropyrazines
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Base-catalysed deuteriation of (3R)- or (3S)-3-isopropyl-2,5-dimethoxy-3,6-dihydropyrazines in refluxing CH3O2H-2H2O gives the -isotopomer in excellent yields without disturbing the stereogenic centre at C-3.These compounds provide convenient and efficient access to a range of (R)- and (S)-α-deuteriated α-amino acids, including serine, aspartic acid, allylglycine and phenylalanine, via alkylation of the butyllithium generated C-6 anion.
- Rose, Janet E.,Leeson, Paul D.,Gani, David
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p. 157 - 166
(2007/10/02)
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