Hydrolyse des sels de phospholium monomères: Préparation et propriétés des oxydes de 1,3-diénylphosphines

1978 ◽  
Vol 56 (18) ◽  
pp. 2486-2490 ◽  
Author(s):  
François Mathey ◽  
Georges Muller
Keyword(s):  
Ring Opening ◽  
Major Product ◽  
Double Bonds ◽  
High Yields ◽  
Hydrolysis Of

The hydrolysis of 3,4-dimethylphospholium salts by thallium ethylate in alcohol yields exclusively the corresponding dienylphosphine oxides by ring opening in the general case. However when one of the phosphorus substituents is benzyl, the dienylphosphine oxide becomes the minor product of the hydrolysis, the major product being the 3-methyl-4-methylene-2-phospholene oxide which results from the cleavage of the P—CH2Ph bond with isomerization of one of the double bonds of the phosphole ring. Deuterolysis of benzylphospholium salts shows that the isomerization does not take place before the hydrolysis. Attempted reduction of the P=O bond of dienylphosphine oxides by phenylsilane yields hydrogenated products. On the contrary, the P=O → P=S conversion by P4S10 occurs without destruction of the dienic system. High yields of diene–Fe(CO)3 complexes are obtained by reaction with Fe3(CO)12. When the two phosphorus substituents are different, two diastereoisomeric complexes are obtained.

REACTION OF 2-METHYL-2-NITRO-1,3-PROPANEDIOL WITH ALKALI

1964 ◽  
Vol 42 (7) ◽  
pp. 1741-1745 ◽  
Author(s):  
A. M. Unrau
Keyword(s):  
Vapor Phase ◽  
Major Product ◽  
Nitrite Ion ◽  
High Yields ◽  
Hydrolysis Of

Hydrolysis of 2-methyl-2-nitro-1,3-propanediol with strong alkali (20% NaOH) resulted primarily, as expected, in a reverse aldol decomposition, although a small but significant quantity of free nitrite ion was detected. Hydrolysis with alkaline borate (pH 10) gave high yields of nitrite ion. Possible mechanisms to explain these results are presented. The major product formed in the borate hydrolysis was identified as 2-C-methyl glycerol (2-methyl-1,2,3-propanetriol). A number of minor products were also detected by vapor-phase chromatography.

scholarly journals Synthesis and Antiproliferative Activity of Phosphorus Substituted 4-Cyanooxazolines, 2-Aminocyanooxazolines, 2-Iminocyanooxazolidines and 2-Aminocyanothiazolines by Rearrangement of Cyanoaziridines

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4265
Author(s):  
Victor Carramiñana ◽  
Ana M. Ochoa de Ochoa de Retana ◽  
Francisco Palacios ◽  
Jesús M. de los de los Santos
Keyword(s):  
Ring Opening ◽  
Human Lung ◽  
Ring Expansion ◽  
Moderate Activity ◽  
A549 Cell Line ◽  
One Pot ◽  
Acidic Conditions ◽  
Lung Adenocarcinoma A549 ◽  
High Yields

Several phosphorus-substituted N-acylated cyanoaziridines 2 and N-carbamoylated cyanoziridines 5 were prepared in good to high yields. N-Acylated cyanoaziridines 2 were used, after ring expansion, in an efficient synthesis of oxazoline derivative 3a and in a completely regio-controlled reaction in the presence of NaI. Conversely, N-carbamoyl cyanoaziridines 5 reacted with NaI to obtain a regioisomeric mixture of 2-aminocyanooxazolines 7. Mild acidic conditions can be used for the isomerization of N-thiocarbamoyl cyanoaziridine 6a into a 2-aminocyanothiazoline derivative 8a by using BF3·OEt2 as a Lewis acid. Likewise, a one pot reaction of NH-cyanoaziridines 1 with isocyanates obtained 2-iminocyanooxazolidines 9 regioselectively. This synthetic methodology involves the addition of isocyanates to starting cyanoaziridines to obtain N-carbamoyl cyanoaziridines 5, which after the ring opening, reacts with a second equivalent of isocyanate to give the final 2-imino cyanooxazolidines 9. In addition, the cytotoxic effect on the cell lines derived from human lung adenocarcinoma (A549) was also screened. 2-Iminooxazolidines 9 exhibited moderate activity against the A549 cell line in vitro. Furthermore, a selectivity towards cancer cells (A549) over non-malignant cells (MCR-5) was detected.

Recent Advances in Transition Metal Catalyzed C-H Functionalization Reactions Involving Aza/Oxabicyclic Alkenes

Synthesis ◽  
2021 ◽  
Author(s):  
Masilamani Jeganmohan ◽  
Pinki Sihag
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Ring Opening ◽  
Bond Activation ◽  
Considerable Progress ◽  
Double Bonds ◽  
Facial Selectivity ◽  
Ring Opening Reactions ◽  
Metal Catalyzed

Bicyclic alkenes, including Oxa- and azabicyclic alkenes can be readily activated by using transition-metal complexes with facial selectivity, because of the intrinsic angle strain on carbon-carbon double bonds of these unsymmetrical bicyclic systems. During last decades considerable progress has been done in the area of ring-opening of bicyclic strained ring by employing the concept of C-H activation. This Review comprehensively compiles the various C-H bond activation assisted reactions of oxa- and azabicyclic alkenes, viz., ring-opening reactions, hydroarylation as well as annulation reactions.

scholarly journals Novel activity of angiotensin-converting enzyme. Hydrolysis of cholecystokinin and gastrin analogues with release of the amidated C-terminal dipeptide

1989 ◽  
Vol 262 (1) ◽  
pp. 125-130 ◽  
Author(s):  
P Dubreuil ◽  
P Fulcrand ◽  
M Rodriguez ◽  
H Fulcrand ◽  
J Laur ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Chloride Ion ◽  
Peptide Bond ◽  
Major Product ◽  
Enzyme Hydrolysis ◽  
Ion Concentration ◽  
Converting Enzyme ◽  
Rabbit Lung ◽  
Hydrolysis Of

ACE (angiotensin-converting enzyme; peptidyl dipeptidase A; EC 3.4.15.1), cleaves C-terminal dipeptides from active peptides containing a free C-terminus. We investigated the hydrolysis of cholecystokinin-8 [CCK-8; Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2] and of various gastrin analogues by purified rabbit lung ACE. Although these peptides are amidated at their C-terminal end, they were metabolized by ACE to several peptide fragments. These fragments were analysed by h.p.l.c., isolated and identified by comparison with synthetic fragments, and by amino acid analysis. The initial and major site of hydrolysis was the penultimate peptide bond, which generated a major product, the C-terminal amidated dipeptide Asp-Phe-NH2. As a secondary cleavage, ACE subsequently released di- or tri-peptides from the C-terminal end of the remaining N-terminal fragments. The cleavage of CCK-8 and gastrin analogues was inhibited by ACE inhibitors (Captopril and EDTA), but not by other enzyme inhibitors (phosphoramidon, thiorphan, bestatin etc.). Hydrolysis of [Leu15]gastrin-(14-17)-peptide [Boc (t-butoxycarbonyl)-Trp-Leu-Asp-Phe-NH2] in the presence of ACE was found to be dependent on the chloride-ion concentration. Km values for the hydrolysis of CCK-8, [Leu15]gastrin-(11-17)-peptide and Boc-[Leu15]gastrin-(14-17)-peptide at an NaCl concentration of 300 mM were respectively 115, 420 and 3280 microM, and the catalytic constants were about 33, 115 and 885 min-1. The kcat/Km for the reactions at 37 degrees C was approx. 0.28 microM-1.min-1, which is approx. 35 times less than that reported for the cleavage of angiotensin I. These results suggest that ACE might be involved in the metabolism in vivo of CCK and gastrin short fragments.

scholarly journals Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions

2018 ◽  
Vol 14 ◽  
pp. 2897-2906 ◽  
Author(s):  
Stanislav V Lozovskiy ◽  
Alexander Yu Ivanov ◽  
Olesya V Khoroshilova ◽  
Aleksander V Vasilyev
Keyword(s):  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Dft Study ◽  
Bronsted Acids ◽  
Allyl Alcohols ◽  
High Yields ◽  
Hydrolysis Of

In strong Brønsted acids (CF3SO3H, FSO3H, D2SO4), (arysulfonyl)allenes (ArSO2–CR1=C=CR2R3) and (arylsulfinyl)allenes (ArSO–CR1=C=CR2R3) undergo cyclization into the corresponding stable 1,2-oxathiolium ions, which were studied by means of NMR and DFT calculations. Quenching of solutions of these cations with low nucleophilic media, aqueous HCl, leads to their deprotonation with a stereoselective formation of (arysulfonyl)butadienes (for instance, ArSO2–CR1=C–C(Me)=CH2, for R2 = R3 = Me, yields of 87–98%). Reactions of (arysulfonyl)allenes in the system TfOH (0.1 equiv)–HFIP (hexafluoropropan-2-ol) followed by hydrolysis give rise to allyl alcohols (ArSO2–CR1=CH–C(OH)R2R3, yields of 78–99%). Reflux of solutions of (arysulfonyl)allenes in the presence of TfOH (1 equiv) in 1,2-dichlorobenzene leads to the cyclization into thiochromene 1,1-dioxides in high yields. Under the action of TfOH or AlX3 (X = Cl, Br) followed by hydrolysis of reaction mixtures, (arylsulfinyl)allenes give allyl alcohols (ArSO2–CR1=CH–C(OH)R2R3). Plausible reaction mechanisms have been proposed for all studied reactions.

Superhydrophobic functionalization of cutinase activated poly(lactic acid) surfaces

2017 ◽  
Vol 19 (3) ◽  
pp. 816-822 ◽  
Author(s):  
A. Ortner ◽  
A. Pellis ◽  
C. Gamerith ◽  
A. Orcal Yebra ◽  
D. Scaini ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Enzymatic Hydrolysis ◽  
Ring Opening ◽  
Superhydrophobic Surfaces ◽  
Poly Lactic Acid ◽  
Hydrolysis Of

Controlled enzymatic hydrolysis of PLA surfaces, followed by ring opening of AKD, leads to superhydrophobic surfaces (WCA >150°).

Synthesen und Strukturen von 2,5-Bis(2-arylvinyl)-1,4-benzochinonen und deren photochemisches Verhalten im Kristall / Syntheses and Crystal Structures of 2,5-Bis(2-arylvinyl)-1,4-benzoquinones and their Photochemical Reactivity in the Crystalline State

1993 ◽  
Vol 48 (10) ◽  
pp. 1411-1418 ◽  
Author(s):  
Hermann Irngartinger ◽  
Jochen Lichtenthäler ◽  
Dieter Fenske ◽  
Gerhard Baum
Keyword(s):  
Crystal Structures ◽  
Anodic Oxidation ◽  
Crystalline State ◽  
Double Bonds ◽  
Resonance Structures ◽  
Photochemical Reactivity ◽  
X Ray ◽  
Bond Lengths ◽  
Intermolecular Distances ◽  
Hydrolysis Of

The 2,5-bis(2-arylvinyl)-1,4-benzoquinones 1a-1e are formed from hydrolysis of their corresponding ketals 5 which are generated by anodic oxidation of the corresponding 1,4-dimethoxybenzene derivatives 4. The crystal structures of the quinone compounds 1a, 1d and 1e have been determined by X-ray analyses. The bond lengths of the quinone system are influenced by polar resonance structures. An α-type packing mode is observed for the three crystal structures of compounds 1. The vinylic double bonds have short intermolecular distances (1a: 4.417(5), 1d: 3.653(2), 1e: 4.224(5) Å). Only the crystals of 1d with the shortest contacts are photoreactive

Ligand-Free Nickel-Catalyzed Reductive Allylic Defluorinative Cross-Coupling of α-Trifluoromethyl Alkenes with Epoxides

Synlett ◽  
2020 ◽  
Author(s):  
Chuan Wang ◽  
Zhiyang Lin ◽  
Yun Lan
Keyword(s):  
Ring Opening ◽  
Cross Coupling ◽  
Proton Donor ◽  
Mild Conditions ◽  
Ligand Free ◽  
High Yields ◽  
Radical Type

We report a reductive allylic defluorinative reaction of α-trifluoromethyl alkenes with terminal epoxides, which consists of an iodide-mediated regioselective ring opening and a nickel-catalyzed radical-type cross-coupling, providing diverse tertiary gem-difluorobishomoallylic alcohols in moderate to high yields. Notably, this reaction is conducted under mild conditions and requires no external ligand or proton donor.

scholarly journals The acidic hydrolysis of N-acetylneuraminic 4,5-oxazoline allows a direct functionalization of the C5 position of Neu5Ac2en (DANA)

RSC Advances ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 162-165 ◽  
Author(s):  
Paola Rota ◽  
Paolo La Rocca ◽  
Federica Cirillo ◽  
Marco Piccoli ◽  
Pietro Allevi ◽  
...  
Keyword(s):  
Ring Opening ◽  
Antiviral Drugs ◽  
Amino Group ◽  
Group Key ◽  
Acidic Hydrolysis ◽  
Direct Functionalization ◽  
Direct Generation ◽  
Hydrolysis Of

The Neu5Ac 4,5-oxazoline ring-opening allows the direct generation of a free C5-amino group key to synthesize antiviral drugs.

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