Carcinogenicity of lactones. V. The reactions of 4-hydroxypent-2-enoic acid lactone with α-toluenethiol, benzylamine, methylamine, imidazole, and guanidine

1970 ◽  
Vol 48 (10) ◽  
pp. 1574-1578 ◽  
Author(s):  
J. Bryan Jones ◽  
Jill N. Barker
Keyword(s):  
Michael Addition ◽  
Ring Opening ◽  
Lactone Ring ◽  
Addition Product ◽  
Enoic Acid ◽  
Michael Additions ◽  
Ring Opening Reactions ◽  
Acid Lactone ◽  
Ph Range ◽  
The Michael Addition

The Michael additions of α-toluenethiol, methylamine, and benzylamine to 4-hydroxypent-2-enoic acid lactone have been confirmed to be facile. The analogous additions of imidazole and glycine amide are much less readily accomplished and no stable Michael addition product could be detected with guanidine as the base. In the pH range 6–9, subsequent lactone ring opening reactions of the Michael addition products were observed only when methylamine (pKa 9.3) and benzylamine (pKa 10.6) were used as nucleophiles.

CARCINOGENICITY OF LACTONES: I. THE REACTION OF 4-METHYLBUTENO- AND 4-METHYLBUTANO-γ-LACTONES WITH PRIMARY AMINES

1966 ◽  
Vol 44 (9) ◽  
pp. 1059-1068 ◽  
Author(s):  
J. Bryan Jones ◽  
John M. Young
Keyword(s):  
Magnetic Resonance ◽  
Michael Addition ◽  
Ring Opening ◽  
Proton Magnetic Resonance ◽  
Mechanisms Of Action ◽  
Reaction Pathways ◽  
Nucleophilic Attack ◽  
Primary Amines ◽  
Acid Lactone ◽  
The Michael Addition

As the first stage in the investigations of the mechanisms of action of carcinogenic lactones, the reactions of 4-hydroxypent-2-enoic acid lactone (II, R = CH3), which is a carcinogen, and of the non-carcinogenic 4-hydroxypent-3-enoic (III, R = CH3) and 4-hydroxypentanoic (IV, R = CH3) acid lactones with methylamine and benzylamine have been studied. As expected, the carcinogenic lactone reacts to give the Michael addition products, whereas both inactive lactones undergo ring opening by nucleophilic attack at the carbonyl group. From the relative rates of reaction of the amines with the lactones it is concluded that the induction of tumors by II (R = CH3) does not involve alkylation of biological primary alkylamino groups. The proton magnetic resonance spectra of the products enable the different reaction pathways to be distinguished readily, and may provide the basis for rapid physicochemical screening of alkylation agents that are potential carcinogens.

scholarly journals Dual-functional materials via CCTP and selective orthogonal thiol-Michael addition/epoxide ring opening reactions

2013 ◽  
Vol 4 (8) ◽  
pp. 2608 ◽  
Author(s):  
Kayleigh A. McEwan ◽  
Stacy Slavin ◽  
Edward Tunnah ◽  
David M. Haddleton
Keyword(s):  
Michael Addition ◽  
Ring Opening ◽  
Functional Materials ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
Dual Functional ◽  
Ring Opening Reactions

scholarly journals Post-polymerisation modification of bio-derived unsaturated polyester resins via Michael additions of 1,3-dicarbonyls

2016 ◽  
Vol 7 (8) ◽  
pp. 1650-1658 ◽  
Author(s):  
T. J. Farmer ◽  
J. H. Clark ◽  
D. J. Macquarrie ◽  
J. K. Ogunjobi ◽  
R. L. Castle
Keyword(s):  
Michael Addition ◽  
Unsaturated Polyester ◽  
Polyester Resins ◽  
Unsaturated Polyesters ◽  
Unsaturated Polyester Resins ◽  
Michael Additions ◽  
First Time ◽  
The Michael Addition

A rapid (5 min), solventless and heterogeneously catalysed methodology is demonstrated for the first time for the Michael addition of 1,3-dicarbonyls to biomass derived unsaturated polyesters.

Phosphato complexes of cobalt(III). II. Reversible chelation and ring-opening reactions

1968 ◽  
Vol 21 (1) ◽  
pp. 57 ◽  
Author(s):  
SF Lincoln ◽  
DR Stranks
Keyword(s):  
Rate Constants ◽  
Ring Opening ◽  
Base Catalysis ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Protonated Forms ◽  
Acid And Base ◽  
Chelation Reaction ◽  
Ph Range ◽  
Monodentate Complex

The bidentate phosphato complex Co en2PO40; has been shown to exist in rapid reversible equilibrium with the monodentate complex Co en2OH.HPO40 A detailed kinetic analysis of the opposed ring-opening and ring-closing (or chelation) reactions has evaluated rate constants for each of the protonated forms in acid and basic media. The ring-opening reaction is subject to both acid and base catalysis. However, within the pH range 6-9, the bidentate form containing a four-member phosphate ring is thermodynamically more stable than the monodentate form. This is ascribed to a rapid chelation reaction arising from a favourable cis hydrogen-bonded transition state.

Michael Addition of Indoles to Enones Catalyzed by a Cationic Iron Salt

Synthesis ◽  
2021 ◽  
Author(s):  
Takashi Nishikata ◽  
Tsukasa Inishi ◽  
Goki Hirata
Keyword(s):  
Lewis Acid ◽  
Michael Addition ◽  
Iron Catalyst ◽  
Unsaturated Ester ◽  
Iron Salt ◽  
Michael Additions ◽  
The Michael Addition

AbstractIndoles are one of the most valuable nucleophiles in Michael additions catalyzed by a proper Lewis acid. In this paper, we found that a cationic iron salt is effective to carry out the Michael addition of indoles. β-Mono- and disubstituted enones reacted smoothly with indoles under our conditions. The cationic iron catalyst is very active, and the maximum TON was up to 425. Moreover, cationic iron-catalyzed conditions enabled a chemoselective Michael addition of a substrate possessing both enone and α,β-unsaturated ester moieties.

Indium(I) iodide promoted cleavage of dialkyl disulfides — Application of the Michael addition of thiolate anions to conjugated carbonyl compounds and regioselective ring opening of epoxides

2006 ◽  
Vol 84 (5) ◽  
pp. 762-770 ◽  
Author(s):  
Brindaban C Ranu ◽  
Tanmay Mandal
Keyword(s):  
Michael Addition ◽  
Ring Opening ◽  
Unsaturated Ketones ◽  
Ring Opening Of Epoxides ◽  
Dialkyl Disulfides ◽  
Carboxylic Esters ◽  
Thiolate Anions ◽  
Neutral Conditions ◽  
Nucleophilic Ring Opening ◽  
The Michael Addition

Indium(I) iodide promotes cleavage of dialkyl disulfides generating thiolate anions that then undergo facile addition to α,β-unsaturated ketones, aldehydes, carboxylic esters, and nitriles under neutral conditions producing corresponding β-ketosulfides or β-cyanosulfides. This strategy has also been used for the regioselective nucleophilic ring opening of epoxides by thiolate anions in presence of indium(III) chloride producing corresponding β-hydroxyphenyl sulfides. The reactions are in general, very clean, high yielding, and reasonably fast. Thus, simple and convenient procedures for the synthesis of β-ketosulfides or β-cyanosulfides and β-hydroxyalkyl sulfides have been developed using this cleavage reaction.Key words: indium(I) iodide, Michael addition, β-ketosulfide, β-cyanosulfide, epoxide, β-hydroxy sulfide.

scholarly journals Importance of the N-terminal proline for the promiscuous activity of 4-oxalocrotonate tautomerase (4-OT)

2016 ◽  
Vol 81 (8) ◽  
pp. 871-881 ◽  
Author(s):  
Jelena Lazic ◽  
Jelena Spasic ◽  
Djordje Francuski ◽  
Zorana Tokic-Vujosevic ◽  
Jasmina Nikodinovic-Runic ◽  
...  
Keyword(s):  
Michael Addition ◽  
Structural Changes ◽  
In Silico Analysis ◽  
Cell System ◽  
Michael Additions ◽  
Lysine Residues ◽  
Negative Effect ◽  
Michael Acceptors ◽  
Organocatalytic Reactions ◽  
The Michael Addition

Michael addition of aldehydes to nitroolefins is an effective method to obtain useful chiral ?-nitroaldehydes. ?-Nitroaldehydes are precursors for chiral ?-aminobytiric acid analogues which have numerous pharmacological activities and are used for treatment of neurological disorders. A whole-cell system based on recombinantly expressed 4-oxalocrotonate tautomerase (4-OT) has been developed and shown to be an effective biocatalyst for Michael addition of branched aldehydes to ?-nitrostyrenes. The aim of this study was to investigate the influence of the substitution of the N-terminal proline with lysine and arginine both containing the reactive ?-amino group, on the Michael addition catalyzed by 4-OT. Firstly, the effect of these mutations was examined by in silico analysis, followed by generation of three terminal ly-sine mutants. The generated mutants, 4-OT_K, 4-OT_PK and 4-OT_KK were tested for the ability to utilise ?-nitrostyrene (1), (E)-2-(thiophene-2-yl)nitroethen (2) and p-chloro-trans-?-nitrostyrene (3) as Michael acceptors with isobutanal as the donor. For comparison, the lithium salt of lysine was used in the same organocatalytic reactions. In general, the introduction of lysine had a negative effect on Michael additions based on overall product yields. However, additional lysine residues at the N-terminus of the protein resulted in structural changes that enhanced the activity towards 2 and 3. Therefore, the N-terminal proline is important for the 4-OT catalysed Michael-additons, but it is not essential.

Ring-opening polymerization of 6-hydroxynon-8-enoic acid lactone: Novel biodegradable copolymers containing allyl pendent groups

2000 ◽  
Vol 38 (5) ◽  
pp. 870-875 ◽  
Author(s):  
D. Mecerreyes ◽  
R. D. Miller ◽  
J. L. Hedrick ◽  
C. Detrembleur ◽  
R. J�r�me
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Enoic Acid ◽  
Biodegradable Copolymers ◽  
Pendent Groups ◽  
Acid Lactone
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