675-20-7Relevant articles and documents
PRODUCTION METHOD OF CYCLIC COMPOUND
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Paragraph 0057; 0059; 0062; 0064, (2021/05/05)
PROBLEM TO BE SOLVED: To provide an industrially simple production method of a cyclic compound. SOLUTION: A production method of a cyclic compound includes a step to obtain a reduced form (B) by reducing an unsaturated bond in a ring structure of an aromatic compound (A) by means of catalytic hydrogenation of the aromatic compound (A) or its salt using palladium carbon as a catalyst under a normal pressure, in which the aromatic compound (A) has one or more ring structures selected from a group consisting of a five membered-ring, a six membered-ring, and a condensed ring of the five membered-ring or the six membered-ring with another six membered-ring, a hetero atom can be included in the ring structure, and the aromatic compound (A) can have one or two side chains bonded to the ring structure and does not have any carbon-carbon triple bond in the side chain. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
En Route to a Heterogeneous Catalytic Direct Peptide Bond Formation by Zr-Based Metal-Organic Framework Catalysts
Conic, Dragan,De Azambuja, Francisco,Harvey, Jeremy N.,Loosen, Alexandra,Parac-Vogt, Tatjana N.,Van Den Besselaar, Maxime
, p. 7647 - 7658 (2021/06/30)
Peptide bond formation is a challenging, environmentally and economically demanding transformation. Catalysis is key to circumvent current bottlenecks. To date, many homogeneous catalysts able to provide synthetically useful methods have been developed, while heterogeneous catalysts remain largely restricted to the studies addressing the prebiotic formation of peptides. Here, the catalytic activity of Zr6-based metal-organic frameworks (Zr-MOFs) toward peptide bond formation is investigated using dipeptide cyclization as a model reaction. Unlike previous catalysts, Zr-MOFs largely tolerate water, and reactions are carried out under ambient conditions. Notably, the catalyst is recyclable and no additives to activate the COOH group are necessary, which are common limitations of previous methods. In addition, a broad reaction scope tolerates substrates with bulky and Lewis basic groups. The reaction mechanism was assessed by detailed mechanistic and computational studies and features a Lewis acid activation of carboxylate groups by Zr centers toward amine addition in which an alkoxy ligand on adjacent Zr sites assists in lowering the barrier of key proton transfers. The proposed concepts were also used to study the formation of intermolecular peptide bond formation. While intrinsic challenges associated with the catalyst structure and water removal limit a more general intermolecular reaction scope under current conditions, the results suggest that further design of Zr-MOF catalysts could render these materials broadly useful as heterogeneous catalysts for this challenging transformation.
Rapid and Mild Lactamization Using Highly Electrophilic Triphosgene in a Microflow Reactor
Fuse, Shinichiro,Komuro, Keiji,Otake, Yuma,Masui, Hisashi,Nakamura, Hiroyuki
supporting information, p. 7525 - 7532 (2021/03/17)
Lactams are cyclic amides that are indispensable as drugs and as drug candidates. Conventional lactamization includes acid-mediated and coupling-agent-mediated approaches that suffer from narrow substrate scope, much waste, and/or high cost. Inexpensive, less-wasteful approaches mediated by highly electrophilic reagents are attractive, but there is an imminent risk of side reactions. Herein, a methods using highly electrophilic triphosgene in a microflow reactor that accomplishes rapid (0.5–10 s), mild, inexpensive, and less-wasteful lactamization are described. Methods A and B, which use N-methylmorpholine and N-methylimidazole, respectively, were developed. Various lactams and a cyclic peptide containing acid- and/or heat-labile functional groups were synthesized in good to high yields without the need for tedious purification. Undesired reactions were successfully suppressed, and the risk of handling triphosgene was minimized by the use of microflow technology.