Abnormal Beckmann rearrangement of steroidal α-chlorocyclobutanone oximes: the fragmentation–substitution reaction

Błaszczyk, Krzysztof; Koenig, Hanna; Mel, Katarzyna; Paryzek, Z.

doi:10.1016/j.tet.2005.11.005

Cited by 17 publications

(9 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…76 The results are interpreted in terms of structural and stereoelectronic effects and are supported by AM1 calculations. The rearrangement of α-chlorocyclobutanone oximes, derivatives of steroids, has been described as characterized by a Beckmann fragmentation-substitution.…”

Section: Dementioning

confidence: 54%

Molecular Rearrangements: Part 2. Other Reactions

Brandi

Gensini

2010

Organic Reaction Mechanisms · 2006

View full text Add to dashboard Cite

The formation of α-phenyl-β-halovinyl cation, β-phenyl-α-halovinyl cation, and also the halogen-bridged and the spirocyclic phenyl-bridged cations, as intermediates of protonation of phenylethynyl halides, or of halogen addition to phenylethynes, has been evaluated by DFT at the B3LYP/6-31+G(d) level and, for comparison in representative cases, by B3LYP/6-311++G(d,p). 1 Structural and mechanistic studies of the lithium diisopropylamide (LDA)-mediated anionic Fries rearrangements of aryl carbamates have been described. 2 Substituents at the meta position of the arene (H, OMe, F) and the dialkylamino moiety of the carbamate (Me 2 N, Et 2 N, and i-Pr 2 N) markedly influence the relative rates of ortholithiation and subsequent Fries rearrangement. The mechanism of the Fries rearrangement of aryl formates promoted by boron trichloride has been studied by means of 1 H, 2 H, and 11 B NMR spectroscopy and DFT calculations. 3 After the formation of a 1:1 substrate -Lewis acid adduct, the rearrangement proceeds in two steps, beginning with the cleavage of the ester bond and the release of formyl chloride in situ, which, in turn, acts as a formylating agent, introducing 451

show abstract

Section: Dementioning

confidence: 54%

Molecular Rearrangements: Part 2. Other Reactions

Brandi

Gensini

2010

Organic Reaction Mechanisms · 2006

View full text Add to dashboard Cite

show abstract

“…Alternatively, controlled dehalogenation of the dichlorocyclobutanone cycloadduct with stoichometric Zn or Zn(Cu) in acetic acid furnished a mixture of regioisomeric monochlorocyclobutanones ( 22 ) contaminated by small amounts of dichloroketone (starting material) and cyclobutanone 3 (overreduction). [11] Hydrogenolysis of the monochlorocyclo butanone as before furnished analog 9 .…”

Section: Resultsmentioning

confidence: 99%

Development of Cyclobutene‐ and Cyclobutane‐Functionalized Fatty Acids with Inhibitory Activity against Mycobacterium tuberculosis

et al. 2014

View full text Add to dashboard Cite

Eleven fatty acid analogs incorporating four-membered carbocycles (cyclobutenes, cyclobutanes, cyclobutanones, and cyclobutanols) were investigated for the ability to inhibit growth of Mycobacterium smegmatis (Msm) and Mycobacterium tuberculosis (Mtb). A number of the analogs displayed inhibitory activity against both mycobacterial species in minimal media. Several of the molecules displayed potent levels of inhibition against Mtb with MIC values equal to or below those obtained with the anti-tuberculosis drugs D-cycloserine and isoniazid. In contrast, two of the analogs displaying the greatest activity against Mtb failed to inhibit E. coli growth under either set of conditions. Thus, the active molecules identified here (1, 2, 6, and 8) may provide the basis for development of anti-mycobacterial agents against Mtb.

show abstract

“…The related cyclobutanone 7 and cyclobutanol 8 were prepared from the dichlorocyclobutanone in a similar manner as described earlier for the C 10 series. Alternatively, controlled dehalogenation of the dichlorocyclobutanone cycloadduct with stoichiometric Zn or Zn(Cu) in acetic acid furnished a mixture of regioisomeric monochlorocyclobutanones 22 contaminated by small amounts of dichloroketone (starting material) and cyclobutanone 3 (over‐reduction) 11. Hydrogenolysis of the monochlorocyclobutanone as before, furnished analogue 9 .…”

Section: Resultsmentioning

confidence: 99%

One‐Dimensional Carbon Nanotube/SnO₂/Noble Metal Nanoparticle Hybrid Nanostructure: Synthesis, Characterization, and Electrochemical Sensing

Fang

Guo

Zhu

et al. 2010

Chemistry An Asian Journal

View full text Add to dashboard Cite

Herein we report a facile and efficient method for self-assembling noble-metal nanoparticles (NPs) to the surface of SnO(2)-coated carbon nanotubes (CNT@SnO(2)) to construct CNT@SnO(2)/noble metal NP hybrids. By using SnCl(4) as the precursor of the SnO(2) shell on the surface of CNTs, the hydrolysis speed of SnCl(4) was slowed down in ethanol containing a trace amount of urea and water. The coaxial nanostructure of CNT@SnO(2) was confirmed by using X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). It was found that the coating layer of SnO(2) was homogeneous with the mean thickness of 8 nm. The CNT@SnO(2)/noble-metal NP hybrids were obtained by mixing noble-metal NPs with as-prepared CNT@SnO(2) coaxial nanocables by means of a self-assembly strategy. With the amino group terminated, the CNT@SnO(2) coaxial nanocable can readily adsorb the as-prepared noble-metal NPs (Au, Ag, Au-Pt, and Au-Pd NPs). The presence of an amino group at the surface of SnO(2) was proved by use of X-ray photoelectron spectroscopy (XPS). In addition, H(2)O(2) sensing by amperometric methods could serve as detection models for investigating the electrocatalytic ability of as-prepared hybrid materials. It was found that wide linear ranges and low detection limits were obtained by using the enzyme-free CNT@SnO(2)@Au-Pt modified electrode, which indicated the potential utilizations of the hybrid based on CNT@SnO(2) for electrochemical sensing.

show abstract

Abnormal Beckmann rearrangement of steroidal α-chlorocyclobutanone oximes: the fragmentation–substitution reaction

Cited by 17 publications

References 60 publications

Molecular Rearrangements: Part 2. Other Reactions

Molecular Rearrangements: Part 2. Other Reactions

Development of Cyclobutene‐ and Cyclobutane‐Functionalized Fatty Acids with Inhibitory Activity against Mycobacterium tuberculosis

One‐Dimensional Carbon Nanotube/SnO₂/Noble Metal Nanoparticle Hybrid Nanostructure: Synthesis, Characterization, and Electrochemical Sensing

Contact Info

Product

Resources

About

Abnormal Beckmann rearrangement of steroidal α-chlorocyclobutanone oximes: the fragmentation–substitution reaction

Cited by 17 publications

References 60 publications

Molecular Rearrangements: Part 2. Other Reactions

Molecular Rearrangements: Part 2. Other Reactions

Development of Cyclobutene‐ and Cyclobutane‐Functionalized Fatty Acids with Inhibitory Activity against Mycobacterium tuberculosis

One‐Dimensional Carbon Nanotube/SnO2/Noble Metal Nanoparticle Hybrid Nanostructure: Synthesis, Characterization, and Electrochemical Sensing

Contact Info

Product

Resources

About

One‐Dimensional Carbon Nanotube/SnO₂/Noble Metal Nanoparticle Hybrid Nanostructure: Synthesis, Characterization, and Electrochemical Sensing