ChemInform Abstract: THE REVERSIBILITY OF THE RING-OPENING STEP IN THE HYDROLYSIS OF TROPONE ETHYLENE KETAL AND TROPONE TRIMETHYLENE KETAL

1979 ◽  
Vol 10 (21) ◽  
Author(s):  
R. A. MCCLELLAND ◽  
M. AHMAD ◽  
G. MANDRAPILIAS
Keyword(s):  
Ring Opening ◽  
Hydrolysis Of

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°).

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.

Arene chromium complexes with functionalized anellated rings. Selective formation of highly substituted polycycles

2002 ◽  
Vol 74 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Holger Butenschön
Keyword(s):  
Good Yield ◽  
Ring Opening ◽  
Ring Expansion ◽  
Chromium Complexes ◽  
Ketone Group ◽  
Aldol Additions ◽  
Cope Rearrangements ◽  
Hydrolysis Of ◽  
Selective Formation ◽  
Tricarbonylchromium Complexes

Tricarbonylchromium complexes of benzocyclobutenone, benzocyclobutenedione, and 1,3-indandione are readily prepared by hydrolysis of the complexes of the corresponding acetals. Reduction of the benzocyclobutenone complex gives rise to an oxy-anion-driven ring opening to the corresponding ortho-quinodimethane intermediate, which can be trapped with dienophiles. Addition of 1-ethoxy-1-lithioethene allows a stereoselective ring expansion followed by an anionic ketol rearrangement with complete diastereoselectivity. Addition of 1-lithio-1-methoxyallene gives rise to a rare anionic 1-vinylcyclobutenol-cyclohexadienol rearrangement. Diaddition of alkenylmetal reagents at both keto groups in benzoyclobutenedione complexes causes dianionic oxy-Cope rearrangements to occur at ­78 °C, which are followed by diastereoselective intramolecular aldol additions. In some cases, a completely regioselective mono hydrolysis of di(enolates) was observed. Dianionic oxy-Cope rearrangements can also be realized with unstrained benzil derivatives giving 1,6-hexanediones and the corresponding aldol adducts. The 1,2,3-indantrione complex is obtained by oxidation of the 1,3-indandione complex with dimethyldioxirane in good yield and reacts with its central ketone group in hetero Diels­Alder cycloadditions.

ChemInform Abstract: Reversibility of the Ring-Opening Step in the Acid Hydrolysis of Cyclic Acetophenone Acetals (I).

ChemInform ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. no-no
Author(s):  
R. A. MCCLELLAND ◽  
B. WATADA ◽  
C. S. Q. LEW
Keyword(s):  
Acid Hydrolysis ◽  
Ring Opening ◽  
Hydrolysis Of

scholarly journals Synthesis of poly(γ-tert-butyl L-glutamate): influence of polymerization conditions

2019 ◽  
Vol 16 (3) ◽  
pp. 25
Author(s):  
Phung Thi Thuy Dung ◽  
Nguyen Thi Le Thu
Keyword(s):  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Attenuated Total Reflection ◽  
Resonance Spectroscopy ◽  
Reaction Conditions ◽  
Tert Butyl ◽  
Ft Ir ◽  
Hydrolysis Of ◽  
Polymerization Conditions

This work presents the synthesis and characterization of poly(γ-tert-butyl L-glutamate) (PtBuLG) via a living ring-opening polymerization procedure of γ-tert-butyl L-glutamate N-carboxyanhydride (tBuLG-NCA). The reaction conditions were investigated to optimize the polymerization yield and molecular weight polydispersity. The synthesized PtBuLG was characterized using nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and attenuated total reflection-Fourier transform infrared (ATR FT-IR. Finally, hydrolysis of PtBuLG resulted in poly(L-glutamic acid) (PLGA).

Ring opening of cyclobutene-1,2-dione and 3-trimethylsilylcyclobutene-1,2-dione. Dimerization/decarbonylation of a bisketene to a ketenylbutenolide

1999 ◽  
Vol 77 (5-6) ◽  
pp. 802-805 ◽  
Author(s):  
Annette D Allen ◽  
Thomas T Tidwell
Keyword(s):  
Ring Opening ◽  
H Nmr ◽  
First Time ◽  
Hydrolysis Of ◽  
Ketene Dimerization

Hydrolysis of 3-trimethylsilyl-4,4-dichlorocyclobut-2-ene-1-one (4) in H2SO4 gave small amounts of cyclobutene-1,2-dione (2a) and 3-trimethylsilylcyclobutene-1,2-dione (2d). Photolysis of 2a gave evidence for the formation of the bisketene (CH=C=O2) (1a) in solution for the first time, as identified by the IR band at 2120 cm-1 and the 1H NMR signal at δ 3.20. Thermolysis of 2d gave evidence for the intermediacy of O=C=CHC(SiMe3)=C=O (1d), with an 1H NMR signal at δ 3.43, and the isolation of the unusual ketenyl lactone 6, which could arise by formation of an unsymmetrical [2+2] ketene dimer from 1d, followed by rearrangement and decarbonylation.Key words: bisketenes, cyclobutenediones, ketene dimerization.

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.

SYNTHESIS OF 4-AMINOBUTYRIC ACID AND 2,4-DIAMINOBUTYRIC ACID FROM BUTYROLACTONE

1958 ◽  
Vol 36 (4) ◽  
pp. 593-596 ◽  
Author(s):  
Guy Talbot ◽  
Roger Gaudry ◽  
Louis Berlinguet
Keyword(s):  
Intermediate Product ◽  
Ring Opening ◽  
Aminobutyric Acid ◽  
Diaminobutyric Acid ◽  
Excellent Yield ◽  
Hydrolysis Of

The ring opening of γ-butyrolactone with 1 mole of potassium phthalimide and the hydrolysis of the intermediate product gave 4-aminobutyric acid with an excellent yield. The condensation of 1 mole of potassium phthalimide with 2-bromo-4-butyrolactone gave a 2-phthalimidolactone which can also be opened by treatment with a second molecule of potassium phthalimide. This diphthalimido acid when hydrolyzed gave, with an excellent yield, 2,4-diaminobutyric acid dihydrochloride.

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