Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2-a]pyridin-5-ones Through Pummerer-Type Reactions

2019 ◽  
Author(s):  
Jingjia Huang ◽  
Gang Hu ◽  
Shaoyu An ◽  
Dongding Chen ◽  
Minglei Li ◽  
...  
Keyword(s):  
Pyridinium Salt ◽  
The Other ◽  
One Pot ◽  
Other Hand

N-alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.

Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2-A]pyridin-5-ones Through Pummerer-Type Reactions

2019 ◽  
Author(s):  
Jingjia Huang ◽  
Gang Hu ◽  
Minglei Li ◽  
Pingfan Li
Keyword(s):  
Pyridinium Salt ◽  
The Other ◽  
One Pot ◽  
Other Hand

N-alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with olefins to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.

scholarly journals Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2-a]pyridin-5-ones Through Pummerer-Type Reactions

2019 ◽  
Author(s):  
Jingjia Huang ◽  
Gang Hu ◽  
Shaoyu An ◽  
Dongding Chen ◽  
Minglei Li ◽  
...  
Keyword(s):  
Pyridinium Salt ◽  
The Other ◽  
One Pot ◽  
Other Hand

N-alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.

Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2-A]pyridin-5-ones Through Pummerer-Type Reactions

2019 ◽  
Author(s):  
Jingjia Huang ◽  
Gang Hu ◽  
Minglei Li ◽  
Pingfan Li
Keyword(s):  
Pyridinium Salt ◽  
The Other ◽  
One Pot ◽  
Other Hand

N-alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhy-dride activated sulfoxides and 4-fluoropyridine deriva-tives, followed by hydrolysis. On the other hand, triflic anhydride activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with olefins to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.

scholarly journals Reaktive E=C(p – p)π-Systeme, XX [1] / Reactive E=C(p–p)π-Systems, XX [1]

1990 ◽  
Vol 45 (2) ◽  
pp. 148-160 ◽  
Author(s):  
Joseph Grobe ◽  
Marianne Hegemann ◽  
Duc Le Van
Keyword(s):  
Chemical Properties ◽  
Vapour Phase ◽  
Diels Alder ◽  
The Other ◽  
Molar Ratio ◽  
One Pot ◽  
Nmr Data ◽  
Other Hand ◽  
And Chemical Properties

The vapour phase pyrolysis of the stannylphosphane Me3SnP(CF3)C2F5 (5) at 330 °C leads to 1,2-elimination of Me3SnF yielding a mixture of the two isomeric perfluorophosphaalkenes F3CP=C(F)CF3 (3) and F5C2P=CF2 (4) in a 3:1 molar ratio. 3 is more labile than 4 and proves to be similar to the perfluoro-3-phosphapent-2-ene F5C2P=C(F)CF3 (2) with respect to NMR data and chemical properties. On the other hand 4 resembles the perfluoro-2-phosphapropene F3CP=CF2 (1). These results have been deduced from the following reactivity studies: (i) The rate of dimerization being higher for 3 than for 4. (ii) Reaction of the mixture with diethylamine yielding the aminophosphane derivative F3CP(NEt2)CF(H)CF3 (13) as a product of 3 and the C-aminophosphaalkene F5C2P=C(F)NEt2 (14) as the derivative of 4. (iii) Reaction of the mixture with methanol giving the methoxyphosphane F3CP(OMe)CF(H)CF3 (15) from 3 and the secondary phosphane F5C2P(H)CF2OMe (16) from 4 as precursors. 3 and 4 prove to be effective dienophiles in reactions with 2,3-dimethyl-1,3-butadiene and 1,3-cyclohexadiene, respectively, producing the corresponding Diels-Alder adducts 9 to 12. For these preparations 5 can be used as an equivalent of 3 in a one-pot procedure at 70 °C. On the other hand the phosphane HP(CF3)C2F5 (8) is suited as precursor for 3 in preparing HX addition products.

scholarly journals Ultrasonic-assisted ruthenium-catalyzed one-pot synthesis of biscoumarins

2016 ◽  
Vol 11 (2) ◽  
pp. 3532-3539 ◽  
Author(s):  
Khalil Tabatabaeian ◽  
Mohammad Ali Zanjanchi ◽  
Manouchehr Mamaghani ◽  
Ali Dadashi
Keyword(s):  
Heterogeneous Catalyst ◽  
Ultrasonic Irradiation ◽  
Zeolite Beta ◽  
The Other ◽  
One Pot ◽  
One Pot Synthesis ◽  
Other Hand ◽  
Ultrasonic Assisted

The Ru-grafted zeolite beta was found to be an excellent heterogeneous catalyst for one-pot synthesis of biscoumarins. This reaction was carried out under reflux condition and ultrasonic irradiation. On the other hand, the catalyst could be recovered for the subsequent reactions and reused without appreciable loss of activity.

scholarly journals Ketones as Electrophile in Nitroaldol Reaction: Synthesis of β,β-Disubstituted- 1,3‑dinitroalkanes and Allylic Nitro Compounds

2021 ◽  
Author(s):  
Alex Gomes ◽  
Douglas de Souza ◽  
Jeronimo Costa ◽  
Vera Lúcia Pereira
Keyword(s):  
Nitro Compounds ◽  
The Other ◽  
Reaction Synthesis ◽  
Basic Catalyst ◽  
Reaction Sequence ◽  
One Pot ◽  
Aliphatic Ketones ◽  
Other Hand ◽  
Nitroaldol Reaction

β,β-Disubstituted-1,3-dinitro compounds were obtained exclusively with an overall yield of 83% through a domino nitroaldol/elimination/1,4-addition process, when excess nitromethane was added to cyclohexanone or butanone using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), as a basic catalyst. On the other hand, β-nitroalcohols could be obtained in 30-84% yield, when nitromethane reacts with different aliphatic ketones in stoichiometric amounts, in the presence of catalytic amounts of K2CO3(s), Amberlyst®-A21 or TBAF.3H2O (tetra-n-butylammonium fluoride trihydrate)/THF (tetrahydrofuran). In addition, a new and versatile route to obtainment of allylic nitro compounds, by treatment of acetylated nitroalcohols and aldehydes in catalytic amounts of DBU or TBAF.3H2O, via a one-pot elimination/nitroaldol reaction sequence, was developed.

Stereocontrolled construction of A.B.C.[6.6.6] tricycle via transannular Diels–Alder reaction of 14-membered macrocycle with acetylene as dienophile

1990 ◽  
Vol 68 (12) ◽  
pp. 2137-2143 ◽  
Author(s):  
Yao-Chang Xu ◽  
Michel Cantin ◽  
Pierre Deslongchamps
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
The Other ◽  
One Pot ◽  
Diels Alder Reaction ◽  
Other Hand ◽  
Tricyclic Compound ◽  
Stereocontrolled Synthesis ◽  
Allylic Chloride

The syntheses of the acyclic dienynes 14a (cis-trans-acetylene) and 14b (trans-trans-acetylene) are described. The tandem macrocyclization and transannular Diels–Alder reaction of the allylic chloride 14b was conducted in the presence of Cs2CO3 at 85 °C in one-pot to provide tricyclic product 16, with the two hydrogens in ring B being cis. On the other hand, treatment of the allylic chloride 14a under the same conditions afforded 14-membered macrocycle 17, which could be transformed at 250 °C into a similar tricyclic product 18 with the two hydrogens in ring B being trans, along with an interesting by-product 19. The mechanism for the formation of 19 is also discussed. Keywords: stereocontrolled synthesis, macrocycle, tricyclic compound, transannular Diels–Alder reaction.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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