Functional group dependence of the acid catalyzed ring opening of biomass derived furan rings: an experimental and theoretical study

2013 ◽  
Vol 3 (1) ◽  
pp. 106-115 ◽  
Author(s):  
Christopher R. Waidmann ◽  
Aaron W. Pierpont ◽  
Enrique R. Batista ◽  
John C. Gordon ◽  
Richard L. Martin ◽  
...  
Keyword(s):  
Ring Opening ◽  
Functional Group ◽  
Theoretical Study ◽  
Acid Catalyzed

scholarly journals Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

2016 ◽  
Vol 12 ◽  
pp. 1765-1771 ◽  
Author(s):  
Pramod R Markad ◽  
Navanath Kumbhar ◽  
Dilip D Dhavale
Keyword(s):  
Amino Acid ◽  
Allyl Alcohol ◽  
Ring Opening ◽  
Functional Group ◽  
Asymmetric Epoxidation ◽  
Oxirane Ring ◽  
Trimethyl Borate ◽  
Pyranose Ring ◽  
Acid Catalyzed ◽  
Sharpless Asymmetric Epoxidation

The C8’-epimeric pyranosyl amino acid core 2 of amipurimycin was synthesized from D-glucose derived alcohol 3 in 13 steps and 14% overall yield. Thus, the Sharpless asymmetric epoxidation of allyl alcohol 7 followed by trimethyl borate mediated regio-selective oxirane ring opening with azide, afforded azido diol 10. The acid-catalyzed 1,2-acetonide ring opening in 10 concomitantly led to the formation of the pyranose ring skeleton to give 2,7-dioxabicyclo[3.2.1]octane 12. Functional group manipulation in 12 gave 21 that on stereoselective β-glycosylation afforded the pyranosyl thymine nucleoside 2 – a core of amipurimycin.

Le radical méthylènecyclopropyle: étude théorique. Chloration par t-BuOCl et réduction par (nBu)3SnH de dérivés cyclopropéniques

1985 ◽  
Vol 63 (9) ◽  
pp. 2511-2521 ◽  
Author(s):  
R. Arnaud ◽  
S. Choubani ◽  
R. Subra ◽  
M. Vidal ◽  
M. Vincens ◽  
...  
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Ring Opening ◽  
Functional Group ◽  
Theoretical Study ◽  
Reduction Process ◽  
Trans Position ◽  
Tertiary Alcohols ◽  
Abstraction Reaction ◽  
Allylic Radical

The allylic chlorination of ethyl 2,3-dialkyl 2-cyclopropenecarboxylate or primary and tertiary alcohols is highly regio- and stereoselective. The halogenated methylenecyclopropane derivative only is observed. In that compound, the halogen substituent and the functional group are in a trans position with respect to the ring. The halogenated allylic compounds of methylenecyclopropane and of cyclopropene undergo reduction by (nBu)3SnH with the same stereochemistry. Products arising from ring opening are also observed. The exocyclic migration of the double bond can be related to the formation of a transient allylic radical. A theoretical study performed within the MNDO (UHF and RHF) framework leads to a planar allylic radical, whatever the substituent. The radical abstraction reaction which takes place during the reduction process is easier for a cyclic carbon atom than for an exocyclic one. In the former case, the faster reaction is obtained for a chlorinated carbon atom.

A Robust, Open-Flask, Moisture-Tolerant, and Scalable Route to Unprotected α/β-Amino Acid N-Carboxyanhydrides

2020 ◽  
Author(s):  
Zi-You Tian ◽  
HUA LU
Keyword(s):  
Amino Acid ◽  
Functional Groups ◽  
Ring Opening ◽  
Biomedical Applications ◽  
Functional Group ◽  
Ring Opening Polymerization ◽  
High Yield ◽  
Synthetic Polypeptides ◽  
Acid Catalyzed ◽  
Hydroxyl Acid

Synthetic polypeptides, commonly prepared by the ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCA), are a family of biomimetic materials with vast biomedical applications. A great hurdle in the pro-duction of synthetic polypeptides is the synthesis of NCA, which requires ultra-dry solvents, Schlenk line/gloveboxes, and the protection of sidechain functional groups. Herein, we report a robust and scalable new method for the production of unpro-tected NCA monomers in air and under moisture. The method employs propylene oxide or epichlorohydrin as an inexpensive and ultra-fast scavenger of hydrogen chloride to prevent NCA from acid-catalyzed decomposition under moist conditions. The broad scope and outstanding functional group tolerance of the method are demonstrated by the successful synthesis of more than 30 different NCAs, including many otherwise inaccessible compounds with reactive functional groups (e.g. hy-droxyl, thiol, and carboxylic acid), at high yield and up to ten-gram scale. The scope of the method can be further extended to various α-hydroxyl acid O-carboxyanhydrides (OCA) and β-amino acid NCAs (βNCA). Given these merits, our strategy holds great potential for revolutionizing the synthesis of NCA and polypeptides, and dramatically expanding the industrial application of synthetic polypeptides

scholarly journals A Robust, Open-Flask, Moisture-Tolerant, and Scalable Route to Unprotected α/β-Amino Acid N-Carboxyanhydrides

2020 ◽  
Author(s):  
Zi-You Tian ◽  
HUA LU
Keyword(s):  
Amino Acid ◽  
Functional Groups ◽  
Ring Opening ◽  
Biomedical Applications ◽  
Functional Group ◽  
Ring Opening Polymerization ◽  
High Yield ◽  
Synthetic Polypeptides ◽  
Acid Catalyzed ◽  
Hydroxyl Acid

Synthetic polypeptides, commonly prepared by the ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCA), are a family of biomimetic materials with vast biomedical applications. A great hurdle in the pro-duction of synthetic polypeptides is the synthesis of NCA, which requires ultra-dry solvents, Schlenk line/gloveboxes, and the protection of sidechain functional groups. Herein, we report a robust and scalable new method for the production of unpro-tected NCA monomers in air and under moisture. The method employs propylene oxide or epichlorohydrin as an inexpensive and ultra-fast scavenger of hydrogen chloride to prevent NCA from acid-catalyzed decomposition under moist conditions. The broad scope and outstanding functional group tolerance of the method are demonstrated by the successful synthesis of more than 30 different NCAs, including many otherwise inaccessible compounds with reactive functional groups (e.g. hy-droxyl, thiol, and carboxylic acid), at high yield and up to ten-gram scale. The scope of the method can be further extended to various α-hydroxyl acid O-carboxyanhydrides (OCA) and β-amino acid NCAs (βNCA). Given these merits, our strategy holds great potential for revolutionizing the synthesis of NCA and polypeptides, and dramatically expanding the industrial application of synthetic polypeptides

Theoretical study of photoinduced ring-opening in furan

2010 ◽  
Vol 133 (16) ◽  
pp. 164309 ◽  
Author(s):  
E. V. Gromov ◽  
A. B. Trofimov ◽  
F. Gatti ◽  
H. Köppel
Keyword(s):  
Ring Opening ◽  
Theoretical Study
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