Novel Approach to 3,4-Dihydro-2(1H)-quinolinone Derivatives via Cyclopropane Ring Expansion

2009 ◽  
Vol 11 (5) ◽  
pp. 1043-1045 ◽  
Author(s):  
Takayuki Tsuritani ◽  
Yuhei Yamamoto ◽  
Masashi Kawasaki ◽  
Toshiaki Mase
Keyword(s):  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Novel Approach

ChemInform Abstract: Novel Approach to 3,4-Dihydro-2(1H)-quinolinone Derivatives via Cyclopropane Ring Expansion.

ChemInform ◽  
2009 ◽  
Vol 40 (30) ◽  
Author(s):  
Takayuki Tsuritani ◽  
Yuhei Yamamoto ◽  
Masashi Kawasaki ◽  
Toshiaki Mase
Keyword(s):  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Novel Approach

scholarly journals A Vinyl Cyclopropane Ring Expansion and Iridium‐Catalyzed Hydrogen Borrowing Cascade

2020 ◽  
Vol 132 (28) ◽  
pp. 11435-11440
Author(s):  
Simon Wübbolt ◽  
Choon Boon Cheong ◽  
James R. Frost ◽  
Kirsten E. Christensen ◽  
Timothy J. Donohoe
Keyword(s):  
Cyclopropane Ring ◽  
Ring Expansion

scholarly journals Purification and initial characterization of an enzyme with deacetoxycephalosporin C synthetase and hydroxylase activities

1987 ◽  
Vol 245 (3) ◽  
pp. 831-841 ◽  
Author(s):  
J E Baldwin ◽  
R M Adlington ◽  
J B Coates ◽  
M J C Crabbe ◽  
N P Crouch ◽  
...  
Keyword(s):  
Metal Ion ◽  
Cyclopropane Ring ◽  
Polyacrylamide Gel Electrophoresis ◽  
Ring Expansion ◽  
Maximum Activity ◽  
Reversible Inhibitor ◽  
Synthetase Activity ◽  
Synthetic Analogue ◽  
Ph Optimum ◽  
Deacetoxycephalosporin C Synthetase

Deacetoxycephalosporin C synthetase (expandase) from Cephalosporium acremonium (Acremonium chrysogenum) was purified to near homogeneity as judged by SDS/polyacrylamide-gel electrophoresis. The enzyme (Mr about 40,000) exhibited a pH optimum around 7.5. It required 2-oxoglutarate (Km 0.04 mM), Fe2+ and O2 as cofactors, and ascorbate and dithiothreitol were necessary for maximum activity. It was stable for over 4 weeks at −70 degrees C in the presence of 1 mM-dithiothreitol. Activity was inhibited by the thiol-quenching reagent N-ethylmaleimide, the metal-ion-chelating reagent bathophenanthroline, and NH4HCO3. The highly purified enzyme also showed deacetoxycephalosporin C hydroxylase (deacetylcephalosporin C synthetase) activity, indicating that both expandase and hydroxylase activities are properties of a single protein. These activities could not be separated by ion-exchange, dye-ligand, gel-filtration or hydrophobic chromatography. A beta-sulphoxide and a 3 beta-methylene hydroxy analogue of penicillin N were synthesized to test as potential intermediates in the ring-expansion reaction, Neither compound was a substrate for the enzyme. A synthetic analogue in which the 3 beta-methyl group and the 2-hydrogen atom of penicillin N were replaced by a cyclopropane ring was not a substrate but was a reversible inhibitor of the enzyme.

scholarly journals Synthesis of Highly Functionalised Furo[3,4-b]pyrans: Towards the Fungal Metabolite (−)-TAN-2483B

2021 ◽  
Author(s):  
◽  
R.M. Kalpani K. Somarathne
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Natural Product ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Ethyl Esters ◽  
Pyran Ring ◽  
Synthetic Strategy ◽  
Alternative Approach ◽  
Synthetic Approaches

<p>Carbohydrate-derived cyclopropanes combine both the stereochemical wealth of carbohydrates and the reactivity of cyclopropanes. A diverse variety of reaction modes for these cyclopropyl carbohydrates can be harnessed for the synthesis of natural products and other targets.  The natural products (−)-TAN-2483A and (−)-TAN-2483B are fungal secondary metabolites displaying a variety of bioactivities such as inhibition of c-src kinase action and parathyroid hormone-induced bone resorption. This thesis described several synthetic approaches to the natural product (−)-TAN-2483B and analogues of (−)-TAN-2483B employing cyclopropane ring expansion.  The synthetic route to (−)-TAN-2483B began with the readily available substrate D-mannose. The pyran ring unsaturation of the natural product was established by a cyclopropanation-ring expansion sequence. A synthetic strategy via dichlorocyclopropane-based intermediates is described in chapter 2. This being unsuccessful, an alternative approach via 2-fomyl-glycal was developed in chapter 3. The chapter 2 and 3 provided a solid background for the achievement of the analogues synthesis illustrated in chapter 4 via dibromocyclopropane. Lewis acid-mediated alkynylation followed by Pdcatalysed carbonylative lactonisation was successfully utilised in the revelation of the furo[3,4-b]pyran ring skeleton. This route afforded analogues of TAN-2483B; the Z-and E-unsaturated ethyl esters 140 and 141 and hydroxy(−)-TAN-2483B 145. The total synthesis of (−)-TAN-2483B was not achieved due to unforeseen obstacles encountered in the deoxygenation of the side arm of 335 (Chapter 4) into the E-propenyl side arm of (−)-TAN-2483B.</p>

Diastereoselective Synthesis of Spirobarbiturate-Cyclopropanes through Organobase-Mediated Spirocyclopropanation of Barbiturate-Based Olefins with Benzyl Chlorides

Synthesis ◽  
2018 ◽  
Vol 51 (04) ◽  
pp. 899-906 ◽  
Author(s):  
Xixi Song ◽  
Junbiao Chang ◽  
Yuanyuan Zhu ◽  
Shuang Zhao ◽  
Minli Zhang
Keyword(s):  
Lewis Acid ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Diastereoselective Synthesis ◽  
Benzyl Chlorides ◽  
Synthetic Utility

The organobase-mediated diastereoselective spirocyclopropanation of barbiturate-based olefins with 2,4-disubstituted benzyl chlorides has been developed. The reactions were carried out efficiently to afford the desired spirobarbiturate-cyclopropanes in up to 95% yield with more than 20:1 dr in favor of anti-isomers. In order to extend synthetic utility of the spiro-products, a Lewis acid induced cyclopropane-ring-expansion isomerization was also demonstrated.

Facile Synthesis of Polysubstituted 2-Pyrones via TfOH-Mediated Ring Expansion of 2-Acylcyclopropane-1-Carboxylates

Synthesis ◽  
2021 ◽  
Author(s):  
Jiru Shao ◽  
Caiyun An ◽  
Sunewang Rixin Wang
Keyword(s):  
Cyclopropane Ring ◽  
Bond Cleavage ◽  
Ring Expansion ◽  
Facile Synthesis ◽  
Aryl Group ◽  
Pyrone Ring ◽  
Donor Acceptor ◽  
Facile Route

A facile route to polysubstituted 2-pyrones from readily available 2-acylcyclopropane-1-aryl-1-carboxylates mediated by TfOH is reported. The strongly donating 1-aryl group is important for directing the C-C bond cleavage of the donor-acceptor cyclopropane ring, which then leads to the formation of the 2-pyrone ring through lactonization.

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