30 research outputs found
Tunable Synthesis of Functionalized Cyclohexa-1,3-dienes and 2‑Aminobenzophenones/Benzoate from the Cascade Reactions of Allenic Ketones/Allenoate with Amines and Enones
A TEMPO-dependent tunable synthesis
of functionalized cyclohexa-1,3-dienes
and 2-aminobenzophenones/benzoate from the one-pot cascade reactions
of allenic ketones/allenoate with amines and enones is presented.
Mechanistically, the construction of the entitled six-membered carbocycles
involves the in situ generation of an enaminone intermediate via the
conjugate addition of allenic ketone with amine followed by its catalyst-
and base-free [3+3] annulation with enone along with the simultaneous
introduction of the valuable amino and carbonyl groups
Tunable Synthesis of Functionalized Cyclohexa-1,3-dienes and 2‑Aminobenzophenones/Benzoate from the Cascade Reactions of Allenic Ketones/Allenoate with Amines and Enones
A TEMPO-dependent tunable synthesis
of functionalized cyclohexa-1,3-dienes
and 2-aminobenzophenones/benzoate from the one-pot cascade reactions
of allenic ketones/allenoate with amines and enones is presented.
Mechanistically, the construction of the entitled six-membered carbocycles
involves the in situ generation of an enaminone intermediate via the
conjugate addition of allenic ketone with amine followed by its catalyst-
and base-free [3+3] annulation with enone along with the simultaneous
introduction of the valuable amino and carbonyl groups
Rhodium(III)-Catalyzed Redox-Neutral Synthesis of Isoquinolinium Salts via C–H Activation of Imines
Redox-neutral
synthesis of isoquinolinium salts via C–H
activation of presynthesized or in situ formed imines and coupling
with α-diazo ketoesters has been realized, where a zinc salt
promotes cyclization as well as provides a counteranion. Under three-component
conditions, both ketone and aldehydes are viable arene sources. The
coupling of imines with diazo malonates under similar conditions afforded
isoquinolin-3-ones as the coupling product
Synthesis of Pyrazolo[5,1‑<i>a</i>]isoindoles and Pyrazolo[5,1‑<i>a</i>]isoindole-3-carboxamides through One-Pot Cascade Reactions of 1‑(2-Bromophenyl)buta-2,3-dien-1-ones with Isocyanide and Hydrazine or Acetohydrazide
A novel and efficient method for
the construction of the pyrazoloÂ[5,1-<i>a</i>]Âisoindole
scaffold via a one-pot three-component cascade
reaction of 1-(2-bromophenyl)Âbuta-2,3-dien-1-one with hydrazine and
isocyanide promoted by a Pd catalyst is described. This cascade process
proceeds through initial condensation of the allenic ketone with hydrazine
followed by Pd-catalyzed isocyanide insertion into the C–Br
bond and intramolecular C–N bond formation. Interestingly,
when acetohydrazide was used in place of hydrazine, a more sophisticated
procedure involving condensation, isocyanide insertion into C–H
and C–Br bonds, deacetylation, and formation of C–C,
C–O, and C–N bonds occurred to afford pyrazoloÂ[5,1-<i>a</i>]Âisoindole-3-carboxamides with good efficiency
Rhodium(III)-Catalyzed Redox-Neutral Synthesis of Isoquinolinium Salts via C–H Activation of Imines
Redox-neutral
synthesis of isoquinolinium salts via C–H
activation of presynthesized or in situ formed imines and coupling
with α-diazo ketoesters has been realized, where a zinc salt
promotes cyclization as well as provides a counteranion. Under three-component
conditions, both ketone and aldehydes are viable arene sources. The
coupling of imines with diazo malonates under similar conditions afforded
isoquinolin-3-ones as the coupling product
Rh(III)-Catalyzed C–C Coupling of Diverse Arenes and 4‑Acyl-1-sulfonyltriazoles via C–H Activation
4-Acyl-1-sulfonyltriazoles
act as versatile carbene reagents in Cp*RhÂ(III)-catalyzed ortho-selective
coupling with arenes via C–H activation. The coupling led to
olefination with possible cyclization, depending on the nature of
the arene
Synthesis of 4‑Acylpyrazoles from Saturated Ketones and Hydrazones Featured with Multiple C(sp<sup>3</sup>)–H Bond Functionalization and C–C Bond Cleavage and Reorganization
In
this paper, an efficient and convenient one-pot synthesis of
diversely substituted 4-acylpyrazole derivatives via copper-catalyzed
one-pot cascade reactions of saturated ketones with hydrazones is
reported. Mechanistically, the formation of the title compounds involves
the in situ formation of an enone intermediate through the dehydrogenation
of a saturated ketone and the [2 + 3] cyclization of the enone with
hydrazone followed by an aromatization-driven C–C bond cleavage
and reorganization. To our knowledge, this is the first example in
which the biologically and pharmaceutically important yet otherwise
difficult-to-obtain 4-acylpyrazole derivatives are directly prepared
from saturated ketones and hydrazones featured with multiple aliphatic
C–H bond functionalization and C–C bond cleavage and
reorganization. Compared with literature methods, this novel process
has advantages such as simple and economical starting materials, a
sustainable oxidant, excellent regioselectivity, and good efficiency
Rhodium(III)-Catalyzed Redox-Neutral Synthesis of Isoquinolinium Salts via C–H Activation of Imines
Redox-neutral
synthesis of isoquinolinium salts via C–H
activation of presynthesized or in situ formed imines and coupling
with α-diazo ketoesters has been realized, where a zinc salt
promotes cyclization as well as provides a counteranion. Under three-component
conditions, both ketone and aldehydes are viable arene sources. The
coupling of imines with diazo malonates under similar conditions afforded
isoquinolin-3-ones as the coupling product
Decomposition Algorithm for the Scheduling of Typical Polyvinyl Chloride Production by Calcium Carbide Method
In our previous work (Tian et al. <i>Ind. Eng. Chem. Res.</i> <b>2016</b>, 55(21), 6161–6174),
a plantwide scheduling
model was presented, which was difficult to solve for industrial scale
instances in acceptable time. Because the vinyl chloride monomer (VCM)
buffer links the continuous process with the batch process, the whole
scheduling problem can be decomposed into the upstream VCM production
processes and the downstream polymerization processes. Thus, a decomposition
algorithm is presented in this paper to accelerate the computation
progress. Using the decomposition algorithm, the polymerization scheduling
optimization problem is first conducted and thus the detailed VCM
demand schedule is obtained. Then, with an off-line model formulated
in advance, the operating states (i.e., start/stop operations) of
arc furnaces are optimized in the second step, which would be the
hard-to-solve binary variables in the plantwide scheduling model.
In the off-line work, the furnaces operating range (i.e., the production
rate) is discretized into multiple operational levels and the corresponding
optimal furnaces selection scheme is then obtained based on the energy
consumption model of the arc furnaces. Finally, the determined binary
variables are embedded into the plantwide scheduling model and thus
a reduced scale scheduling optimization is executed. Computational
results show that the proposed algorithm can accelerate the computation
greatly and the scheduling results are close to or even better than
those given in our previous work
Synthesis of α‑Formylated <i>N</i>‑Heterocycles and Their 1,1-Diacetates from Inactivated Cyclic Amines Involving an Oxidative Ring Contraction
A novel synthesis
of pyrrolidine-2-carbaldehydes or tetrahydropyridine-2-carbaldehydes
from the cascade reactions of <i>N</i>-arylpiperidines or <i>N</i>-arylazepanes is presented. Mechanistically, the formation
of the title compounds involves an unprecedented oxidative ring contraction
of inactivated cyclic amines via CuÂ(OAc)<sub>2</sub>/KI/O<sub>2</sub>-promoted oxidative cleavage and reformation of the C–N bond.
Interestingly, when PhIÂ(OAc)<sub>2</sub> was used in place of KI,
1,1-diacetates of the corresponding aldehydes were directly obtained
with good efficiency. To the best of our knowledge, this is the first
example of regioselective CÂ(sp<sup>3</sup>)–H bond functionalization
and CÂ(sp<sup>3</sup>)–N bond activation of saturated cyclic
amines using copper salt and oxygen