Synthesis of α,β-Dicarbonylhydrazones by Aerobic Manganese-Catalysed Oxidation

Article abstract of DOI:10.1002/adsc.201800601

A practical, simple, and efficient manganese-catalysed oxidation of C(sp²)?H bond in readily available β-carbonylenehydrazine under aerobic conditions has been developed. This protocol exhibits a wide range of functional group tolerance in β-carbonylenehydrazines to afford α,β-dicarbonylhydrazones. Experimental and theoretical results suggest that the reaction very likely proceeds through a radical pathway via a hydrogen-atom-transfer process promoted by a Mn^III species. (Figure presented.).

Full text of DOI:10.1002/adsc.201800601

Title: Synthesis of α,β-dicarbonylhydrazones by aerobic manganese-
catalysed oxidation.
Authors: Carlos J. Carrasco, Francisco Montilla, Eleuterio Álvarez, and
Agustin Galindo
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Adv. Synth. Catal. 10.1002/adsc.201800601
Link to VoR: http://dx.doi.org/10.1002/adsc.201800601

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
FULL PAPER
DOI: 10.1002/adsc.201((will be filled in by the editorial staff))
Synthesis of ,β-dicarbonylhydrazones by aerobic manganese-
catalysed oxidation.
Carlos J. Carrasco,a Francisco Montilla, a* Eleuterio Álvarez,b and Agustín Galindo a *
a
Departamento de Química Inorgánica, Facultad de Química, Universidad de Sevilla, Aptdo 1203, 41071 Sevilla, Spain.
Instituto de Investigaciones Químicas, CSIC-Universidad de Sevilla, Avda. Américo Vespucio 49, 41092 Sevilla,
b
Spain.
E-mail: montilla@us.es, galindo@us.es
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.
Abstract. A practical, simple, and efficient manganese-catalysed oxidation of C(sp2)-H bond in readily available β-
carbonylenehydrazine under aerobic conditions has been developed. This protocol exhibits a wide range of functional
group tolerance in β-carbonylenehydrazines to afford ,β-dicarbonylhydrazones. Experimental and theoretical results
suggest that the reaction very likely proceeds through a radical pathway via a hydrogen-atom-transfer process promoted by
a MnIII species.
Keywords: C-H oxidation; manganese catalysis; molecular oxygen; ,β-dicarbonyl compounds
acid (IBX),[26] Dess–Martin reagent[27] or cerium(IV)
Introduction
salts,[28] often lead to further oxidation or side
reactions because of the strong reaction conditions
employed. Additionally, these processes usually
require stoichiometric or large excess of oxidants and,
consequently, generate substantial quantities of waste,
which is increasingly considered undesirable due to
environmental considerations. Therefore, searching
for a mild and green procedure is timely.[29–32]
We recently reported the synthesis of the β-
ketoenehydrazines 2a and 2g, and their use as
precursors of monoanionic bidentate ligands
coordinated to Ni(II) and Cu(II) complexes.[33]
During the attempts of synthesis of the corresponding
coordination compound of Mn(II), by the reaction of
2a with Mn(OAc)2 in aerobic conditions (Scheme 1),
we observed the presence of a unexpected new
product. This was identified by MS, NMR
spectroscopic analysis and single crystal X-ray
structure (see below Figure 2) as the ,β-
diketohydrazone 3a, which is the oxidation product
of 2a.
The activation of molecular oxygen for the selective
oxidation of organic substrates is an essential
transformation in organic chemistry at both a
laboratorial and industrial level.[1] However, this
transformation features important drawbacks such as
the high kinetic stability of O2 towards reactions at
room temperature and the thermodynamic tendency
of molecular oxygen to afford the total oxidation of
the organic substrates (i.e. combustion). Thus,
hydrocarbons usually react with O2 via a complex
free-radical pathway called autooxidation.[2] These
reactions are typically not selective and offer little
synthetic utility. Therefore, developing new selective
procedures to oxidize C-H bonds under an aerobic
atmosphere are particularly desirable.[3] Accordingly,
both metal-free systems[4–6] and transition metal
complexes[7–18] have been well-established to be
active catalysts in this process.
On the other hand, the oxidation of a methylene
group  to a carbonyl group to form vicinal
dicarbonyl compounds is an important transformation
which has many applications in organic synthesis as
building blocks for the synthesis of bioactive
In this paper, we describe a mild and practical
protocol for manganese-catalysed aerobic oxidation
of C(sp2)-H bonds in β-carbonylenehydrazine
compounds to afford novel ,β-dicarbonylhydrazones.
To the best of our knowledge, this is the first reported
synthesis of a α,β-dicarbonylhydrazone framework.
molecules,
especially
those
containing
heterocycles.[19–24] Conventional reagents for
accomplishing this transformation, including strong
oxidants such as selenium oxide,[25] 2-iodoxybenzoic
1
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
Scheme 1. Synthesis of compound 3a and related Ni and Cu complexes under aerobic conditions
reduced with a deviation of the N2 atom from the
plane defined for the substituents of 0.02 and 0.31 Å
for 2c and 2i, respectively.
Results and Discussion
Table 1. Synthesis of β-carbonylenehydrazines 2a-o.
Starting β-carbonylenehydrazines compounds, 2a-o,
were easily obtained, using literature procedures,[34,35]
by treating the readily available β-dicarbonyl
compounds, 1a-f, and the corresponding N,N-
disubstituted hydrazine, R3R4NNH2. The results are
summarised in Table 1. Compounds 2a-i were
isolated as brown crystalline solids, while the
methylphenylhydrazine derivatives 2j-l and the
dimethylhydrazine derivatives 2m-o were isolated as
brownish oils. Analytical and spectroscopic
characterization suggested for all of them a β-
carbonylenehydrazine structure that is preferential
respecting to the others possible tautomers.[33] For
R1
R2
R3
R4
Product
2ab)
2b
Yield (%)a)
Me
Me
Me
Me
Me
Me
Ph
OMe
OEt
NEt2
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Me
Me
Me
Ph
Ph
Ph
Ph
Ph
Ph
Me
Me
Me
Me
Me
Me
Me
Me
Me
57
51
73
72
40
14
68
73
30
96
22
53
69
99
99
2c
1
2dc)
2e
instance, the H NMR spectra shown a singlet at 4.6-
5.9 ppm that was attributed to the C-H proton in the 
position. Additionally, compounds 2a-e, 2g-k and
2m-n showed a low-field singlet at 9.6-12.7 ppm that
were attributed to the N-H hydrazinic proton, which
suggested the presence of a strong intramolecular
hydrogen bond with the carbonyl oxygen atom,[36]
and should be responsible for the stabilisation of the
β-carbonylenehydrazine isomer in the enehydrazine-
hydrazone tautomerism.[33] Conversely, the signal
corresponding to the NH hydrazinic proton for the
cyclohexane-1,3-dione derivatives 2f, 2l and 2o were
found to be shifted to high-field (7.0-9.0 ppm),
showing that intramolecular hydrogen bond was
-(CH2)3-
2f
Me
Me
Ph
OMe
OEt
NEt2
2gb)
2h
Me
Me
Me
Me
2i
2j
2k
2l
2md)
2n
-(CH2)3-
Me
Me
Me
Ph
-(CH2)3-
2o
impeded
in
these
compounds.
The
β-
a) Isolated yield. b) Reported in ref. [33]. c) Reported in ref.
carbonylenehydrazine structure was confirmed by X-
ray diffraction in compounds 2c and 2i (Figure 1).
Selected bond distances and angles are given in Table
S1 (Supporting Information). Both compounds were
characterised by a strong intramolecular hydrogen
bond between the hydrogen atom attached to the N1
atom and the O1 oxygen atom (N-H...O distances of
2.125 and 2.031 Å for 2c and 2i, respectively). This
interaction imposes a planar distribution of the O1-
C1-C2-C3-N1 atoms (maximum deviation from the
plane of 0.01 Å). The C1-C2 bond length is longer
than the C2-C3 one (ca. 1.43 versus ca. 1.36 Å,
respectively) and the C1-O1 distance is typical of a
carbonyl moiety (around 1.22 Å). These data are in
agreement with a localised β-carbonylenehydrazine
formulation. The pyramidalization at the N2 atom is
[35]. d) Reported in ref. [34].
The β-ketoenehydrazine 2g was selected as the
appropriate substrate to establish a general procedure
for the oxidation. Reactions were carried out on the
0.5 mmol scale using ethanol as solvent and one bar
of oxygen pressure at 60ºC The reactions were
1
monitored by H NMR analysis and the results are
summarised in Table 2. Several common first-row
transition-metal salts were initially tested as catalysts.
It is worth mentioning that spontaneous oxygenation
of the β-ketoenehydrazine does not occur in the
absence of metal complex catalyst (entry 1). No
oxidation reaction of substrate 2g was also observed
in the presence of zinc(II) or nickel(II) salts, such as
2
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
Table 3. Synthesis of vicinal ,β-dicarbonylhydrazones by
Zn(OAc)2 (entry 2) and Ni(OAc)2 (entry 3). Copper
or iron salts, such as Cu(OAc)2 (entry 4) and FeCl3
(entry 5), only afforded low yields of the oxidised
product after 18 h of reaction. As we expected,
manganese(II) salts afforded the best yield for the
vicinal dicarbonyl compound 3g. When MnBr2 was
used as the Mn(II) source, a 70% yield of 3g was
obtained after 18 h at 60 ºC (entry 6), while almost
complete formation of 3g was observed with
Mn(OAc)2 as catalyst under the same reaction
conditions (entry 7). At this point, the catalytic
oxidation was repeated, maintaining Mn(OAc)2 as
catalyst, but testing several reaction parameters in
order to optimize the reaction. Thus, the yield to
compound 3g decreased by reducing the reaction time
to 1h (24%, entry 8) or to 2h (72%, entry 9),
respectively. Finally, the reaction was also
incomplete both by using air at atmospheric pressure
(75%, entry 10) or by decreasing the temperature to
25 ºC (83%, entry 11).
aerobic Mn-catalysed oxidation.a)
Product
Yield %b)
R2 = Me, 3a
R2 = Ph, 3b
31
76
66
97
62
R2 = OMe, 3c
R2 = OEt, 3d
R2 = NEt2, 3e
R2 = Me, 3g
R2 = Ph, 3h
R2 = OMe, 3i
R2 = OEt, 3j
R2 = NEt2, 3k
91
71
59
73
46
R2 = Me, 3m
R2 = Ph, 3n
38 c)
50
2c
2i
43
3o
Figure 1. X-Ray structures of compounds 2c and 2i.
Hydrogen atoms were omitted for clarity with the
exception of the N-H atom.
a)
Reaction conditions: catalyst: Mn(OAc)2·4H2O (0.0125
mmol), β-keto-enehydrazine (0.5 mmol), solvent: EtOH
b)
(10 mL), oxidant: O2 (1 atm), t = 18 h, T = 60 °C.
Table 2. Screening of reaction conditions for the oxidation
of β-ketoenehydrazines.a)
Isolated yield. c) Yield determined by NMR.
In order to generalise the developed procedure,
different β-carbonylenehydrazines with different
functional groups were tested, using Mn(OAc)2 as
manganese(II) source and the optimised reaction
conditions described in Table 2 (entry 7). The results
obtained in this study are shown in Table 4. In
general, the system yielded moderate to good yields
Entry
1
2
3
4
Catalyst
-
Zn(OAc)2
Ni(OAc)2
Cu(OAc)2
FeCl3
Yield, %b)
-
-
-
<10
<5
70
>95
24
72
75
83
of
the
corresponding
including
vicinal
,β-
dicarbonylhydrazones,
,β-diketones
(3a,b,g,m,h,n,o), ,β-ketoesters (3c,d,i,j), and ,β-
ketoamides (3e,k), while no reaction were found for
the cyclohexane-1,3-dione derivatives 2f and 2l.
Compounds 3a and 3c-l were isolated as crystalline
solids, while the diphenylhydrazone 3b and the
dimethylhydrazone derivatives 3m-o were isolated as
orange oils. Analytical and spectroscopic data
5
6
7
MnBr2
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
8c)
9d)
10e)
confirmed
the
formation
of
the
,β-
11f)
dicarbonylhydrazone derivatives 3a-e. 3g-k and 3m-o,
respectively. For instance, the two singlets,
corresponding to the C-H proton in the  position and
the N-H hydrazinic proton observed in compounds 2
a)
Reaction conditions: catalyst (0.0125 mmol), β-
ketoenehydrazine 2g (0.5 mmol), EtOH (10 mL), oxidant:
O2 (1 atm). T = 60 ºC, t = 18 h. b) Determined by 1H NMR
analysis. c) t = 1 h. d) t = 2 h. e) Air at atmospheric pressure.
f) T = 25 ºC.
1
disappeared in the H NMR spectra, while a new
signal at 187-205 ppm, corresponding to a new
carbonyl group appeared in the 13C{1H} NMR spectra.
3
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
The molecular structure of some of these derivatives
was confirmed by X-ray crystallography. Structures
of diphenylhydrazone derivatives 3a, 3c and 3d and
methylphenylhydrazone derivatives 3i and 3k are
shown in Figure 2, while selected bond distances and
angles are given in Table S1 (Supporting
Information). The C=O distances of 3 compounds are
again typical of carbonyl bonds, being that of the 
carbonyl group slightly shorter (around 1.20 Å) than
that of the  carbonyl group (around 1.22 Å). The
hydrazone N1-C3 bond is typical of a N=C double
bond (ca. 1.30 Å), while the value of ca. 1.33 Å for
the N1-N2 distance is indicative of a N-N single bond.
All these compounds showed as common structural
features: (i) a similar torsion angle between the two
carbonyl groups, which is close to 90º; and (ii) a
planar arrangement of the N2-N1-C3-C2-O3 atoms
(maximum deviation from the plane less of 0.03 Å).
allowing a fair comparison of activity. The addition
of
Table 4. Influence of additives in the aerobic Mn-catalysed
oxidation of β-ketoenehydrazines.a)
Entry
Catalyst
Additive
-
Bipy (1 eq)
Bipy (4 eq)
Tempo (1eq)
Tempo (4eq)
Tempo (1eq)
Yield%b)
72
92
1
2
3
4
5
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
Mn(OAc)2
88
20 c)
8 d)
6 e)
0 f)
a)
Reaction conditions: catalyst (0.0125 mmol), β-keto-
enehydrazine 2g (0.5 mmol), EtOH (10 mL), oxidant: O2
b)
1
(1 atm). T = 60 ºC, t = 2 h. Determined by H NMR
c)
analysis. TEMPO-substrate adduct 4 was obtained in
20% yield. d) TEMPO-substrate adduct 4 was obtained in
e)
25% yield. Reaction carried out under N2 atmosphere
and 18 h. f) TEMPO-substrate adduct 4 was not observed.
one equivalent of 2,2’-bipyridine (bipy) led to a slight
increase of the yield of the vicinal ,β-
dicarbonylhydrazone 3g (entry 2) respecting to the
reaction performed without additive (entry 1). A
similar result was observed when an excess of bipy (4
eq) was added (entry 3). These results could be
compatible with a reaction mechanism involving
species that contain either the β-ketoenehydrazine or
its monoanionic form as a bidentate ligand
coordinated to the manganese complex, in a similar
way that the previously observed with Ni(II) and
Cu(II) complexes.[33] Thus, the presence of bipy,
which is well-known to form 1:1 complexes with
manganese(II) acetate,[37,38] could share with this
ligand the metal coordination sphere, which give an
increase in the yield of the oxidation catalytic process.
However, the data are not conclusive proofs of
coordination of substrates 2 to manganese. By other
hand, the addition of one equivalent of the radical
3a
3c
3d
3i
scavenger
2,2,6,6-tetramethyl-1-piperidinyloxy
3k
(TEMPO) into the reaction system led to the partial
suppression of the oxidation process (entry 4). When
an excess of TEMPO (4 eq) was added (entry 5),
further decrease of the oxidation product 3g was
observed, although no complete suppression was
achieved. Interestingly, a new species was detected,
which could be identified by NMR and ESI-MS
analysis as the TEMPO-substrate adduct 4, obtained
by the -oxyamination of the β-ketoenehydrazine 2g
and the free radical TEMPO.-Oxyamination
between 1,3-dicarbonyl compounds and TEMPO has
been already reported.[39–42] The formation of this
adduct was almost undetectable when reacted
Figure 2. X-Ray structures of compounds 3a,c,d,i,k.
Hydrogen atoms were omitted for clarity
Additional studies were further conducted in order
to gain insights into the reaction mechanism. The
effect of different additives in the aerobic Mn-
catalysed oxidation of the β-ketoenehydrazine 2g,
under the optimal reaction conditions, is showed in
Table 4. The reaction time was set to 2 h in order to
be sure that the reactions did not run to completion,
4
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
compound 2g and TEMPO in the absence of oxygen
(entry 6). However, the adduct could be obtained in a
Scheme 2. Synthesis of the adduct 4.
Scheme 3. Studies on the reaction mechanism.
Scheme 4. Proposed mechanism for the O2 activation by Mn(II) and the subsequent C-H oxidation.
45 % yield by the reaction of compound 2g and
TEMPO using Mn(OAc)3 as stoichiometric oxidant
(Scheme 2). These results support a radical pathway
promoted by MnIII, which is obtained by the
oxidation of MnII with molecular oxygen.
The oxidation process is specific for -
carbonylenehydrazine substrates. Thus, as shown in
5
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
Scheme 3, oxidation of -C-H bonds were not
observed in β-dicarbonyl compounds, such as 2,4-
pentanedione (1a) or methyl 3-oxobutanoate (1c), in
the presence of Mn(OAc)2 as catalyst and the
optimised reaction conditions described in Table 2.
The same negative result was obtained with β-
ketoenamine compounds, such as 5 or 6, obtained by
the condensation of 2,4-pentanedione (1a) and the
corresponding aniline
Based on the control experiments, a plausible
mechanism for this reaction is proposed in Scheme 4.
Firstly, MnII complex is oxidised to a hidroxo MnIII
species under aerobic conditions.[43–45] Subsequently,
the β-carbonylenehydrazine compound 2 is converted
into the related radical species A via a hydrogen-atom
(H·)-transfer (HAT) process,[46,47] which is promoted
by the MnIII species, via formation a MnIII-
enolate.[44,45,48,49] The formation of radical species A
is demonstrated by the formation of the TEMPO-
substrate adduct. This fact suggests that A may react
with oxygen to get the peroxide radical species B.
Finally, two alternative routes can be proposed for the
last step of the mechanism to afford compound 3:
(Route I) protonation of peroxide species B to afford
the hydroperoxide species C, followed by elimination
of water and (Route II) elimination of OH radical
from the peroxido radical species B.
determined by X-ray diffraction (see optimised
structures in Table S4, Supporting Information). The
oxidation reactions from 2 to 3 are clearly exergonic
with Gibbs energy values within the range -64 – -70
kcal‧ mol-1 (see Table S4). Compounds 2g and 3g
were selected to analyse further details. In particular,
the last step of the mechanism to afford complex 3g
was investigated (Scheme 5). Intermediates Bg and
Cg were optimised and transition states for both
pathways, TS1 and TS2, respectively, were located
(see these structures in Figure 3). The G≠ barrier for
the water extrusion from Cg, 39.7 kcal‧ mol-1, is
higher than the OH radical elimination from Bg, 33.7
kcal‧ mol-1, suggesting that the latter process is
probably the last step in the oxidation mechanism
from 2g toward 3g (i.e. Route II in Scheme 4).
Bg
Cg
TS1
TS2
Figure 3. Optimised structures of the intermediates Bg and
Cg and transition states TS1 and TS2.
Conclusion
In summary, we have developed a mild and practical
approach
for
the
synthesis
of
,β-
dicarbonylhydrazones from β-carbonylenehydrazines
in the presence of Mn(OAc)2 under molecular oxygen.
Our study have shown that manganese-catalysed
aerobic oxidation of C(sp2)-H bonds in β-
carbonylenehydrazine compounds occur through a
mechanism that involve radical species via HAT
process. The study of further applications of this
research is underway.
Scheme 5. Pathways for the formation of 3g from peroxido
radical species B, Route II, and from the hydroperoxide
species C, Route I.
In order to gain further insights into the oxidation
mechanism, selected Density Functional Theory
(DFT) calculations were performed. Geometry
optimizations without symmetry restrictions were
carried out with compounds 2 and 3. The selected
combination of method and basis sets provides a
good structural description of these compounds based
on the comparison of the structural parameters of the
optimised structures with those experimentally
Experimental Section
General Information. Synthetic reactions were performed
under aerobic conditions. Solvents were purified
appropriately prior to use, using standard procedures.
Chemicals were obtained from commercial sources and
used as supplied. Infrared spectra were recorded on a
Perkin-Elmer FT-IR Spectrum Two (pressed KBr pellets).
6
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
NMR spectra were recorded using Bruker AMX-300 or
Avance III spectrometers at the Centro de Investigaciones,
Tecnología e Innovación (CITIUS) of the University of
Sevilla. 13C{1H} and 1H shifts were referenced to the
residual solvent signals and all data are reported in ppm
downfield from TMS. High-resolution mass spectra were
carried out by using a Q-Exactive Hybrid Quadrupole-
Orbitrap Mass Spectrometer from Thermo Scientific at
CITIUS of the University of Sevilla.
CO–CH–CNN), 7.06 (m, 4H, CH ortho, Ph), 7.16 (m, 2H,
CH para, Ph), 7.31 (m, 4H, CH meta, Ph), 10.17 (s, 1H,
NH). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 14.5 (s,
OCH2CH3), 18.5 (s, CH3–CNN), 58.9 (s, OCH2CH3), 84.9
(s, CO–CH–CNN), 119.1 (s, C ortho, Ph), 122.9 (s, C para,
Ph), 129.3 (s, C meta, Ph), 146.6 (s, C ipso, Ph),163.1 (s,
CNN), 170.1 (s, CO). Elemental analyses calculated for
C32H40MoN4O7: C, 55.81; H, 5.85; N, 8.14. Experimental:
C, 56.88; H, 5.60; N, 8.03%.
Synthesis of β-carbonylenehydrazines. The syntheses of
β-carbonylenehydrazines compounds 2a and 2g have been
reported previously by us.[33] Compounds 2d[35] and 2m[34]
have been previously described, but the experimental
procedures employed vary slightly and are here described.
(Z)-3-(2,2-diphenylhydrazinyl)-N,N-diethylbut-2-
enamide,
2e,
and
its
tautomer
3-(2,2-
diphenylhydrazineylidene)-N,N-diethylbutanamide,
2e’: This tautomer mixture was prepared following a
procedure analogous to that described for compound 2b,
but using N,N-diphenylhydrazine hydrochloride (0.834 g,
3.67 mmol), Et3N (0.52 mL, 3.67 mmol) and N,N-diethyl-
3-oxobutanamide (0.5 mL, 3.06 mmol). The resulting
residue was purified by chromatography (1:3 AcOEt /
Petroleum ether as eluent) obtaining a brown crystalline
solid identified as the tautomer 1:1 mixture 2e and 2e’,
according to NMR analysis (0.40 g, 40% yield). IR (KBr,
(Z)-3-(2,2-diphenylhydrazinyl)-1-phenyl-but-2-en-1-one,
2b: NEt3 (0.84 mL, 6 mmol) was added to a solution of
N,N-diphenylhydrazine hydrochloride (1.37 g, 6 mmol) in
toluene (15-25 mL). After 5–10 min of stirring, 1-phenyl-
butane-1,3-dione (1.0 g, 6 mmol) was also added and the
resulting mixture was stirred at 80 °C for 20 h. The
mixture was filtered and the resulting toluene solution was
concentrated to dryness. The residue was purified by
chromatography (1:20 AcOEt / Petroleum ether as eluyent)
obtaining a brown crystalline solid identified as 2b (1.0 g,
−
1
cm ): 3653, 3321, 3190, 3088, 3063, 3038, 3025, 2933,
2873, 2595, 2364, 2333, 2241, 1940, 1857, 1788, 1722,
1620, 1591, 1492, 1460, 1433, 1412, 1379, 1362, 1313,
1276, 1220, 1206, 1177, 1150, 1118, 1112, 1098, 1080,
1049, 1029, 997, 958, 932, 915, 905, 889, 830, 771, 750,
694, 654, 620, 587, 548, 506, 488, 467, 451, 444, 439, 432,
426, 420, 416, 413, 406, 403. 1H NMR (CDCl3, 300 Hz): δ
1.13-1.26 (m, 12H, NCH2CH3, 2e and 2e’), 1.67 (s, 1H,
CO–CH2–CNN, 2e’), 1.87 (s, 3H, CH3–CNN, 2e’), 1.95 (s,
3H, CH3–CNN, 2e), 3.39-3.48 (m, 8H, NCH2CH3, 2e and
2e’), 3,52 (s, 1H, CO–CH2–CNN, 2e’), 4.72, (s, 1H, CO–
CH–CNN, 2e), 7.00-7.09 (m, 8H, CH ortho, Ph, 2e and
2e’), 7.17-7.20 (m, 4H, CH para, Ph, 2e and 2e’), 7.26-7.33
(m, 8H, CH meta, Ph, 2e and 2e’), 11.14 (s, 1H, NH, 2e).
13C{1H} NMR (CDCl3, 75,47 Hz): δ 13.0 (s, CH3–CNN,
2e’), 14.3, 19.1 (s, NCH2CH3, 2e and 2e’), 19.9 (s, CH3–
CNN, 2e), 40.0 (s, CO–CH2–CNN, 2e’), 42.2, 44.4 (s,
NCH2CH3, 2e and 2e’), 84.5 (s, CO–CH–CNN, 2e), 119.1,
121.3 (s, C ortho, Ph, 2e and 2e’), 122.4-123.0 (s, C para,
Ph, 2e and 2e’), 129.0, 129.1 (s, C meta, Ph, 2e and 2e’),
147.0, 148.1 (s, C ipso, Ph, 2e and 2e’), 160.2 (s, CNN,
2e’), 166.5 (s, CNN, 2e), 167.9 (s, CO, 2e), 169.3 (s, CO,
2e’). ESI-MS: found m/z 324.206 for [2e +1]+, calculated
for C20H25N3O, 323.200.
−
1
51% yield). IR (KBr, cm ): 3055, 1587, 1577, 1542, 1492,
1421 ,1377, 1318, 1273, 1181, 1082, 1064, 1026, 999, 931,
908, 847, 806, 772, 752, 711, 693, 681, 619, 613, 567, 536,
503. 1H NMR (CDCl3, 300 Hz): δ 2.15 (s, 3H, CH3–CNN),
5.88 (s, 1H, CO–CH–CNN), 7.06-7.12 (t, 2H, J = 7.2 Hz,
CH para, Ph–N), 7.18-7.22 (m, 4H, CH ortho, Ph–N),
7.31-7.37 (m, 4H, CH meta, Ph–N), 7.42-7.50 (m, 3H, CH
meta and para, Ph–CO), 7.94-7.97 (d, 2H, J = 7.5 Hz, CH
ortho, Ph–CO), 12.66 (s, 1H, NH). 13C{1H} NMR (CDCl3,
75,47 Hz): δ 18.8 (s, CH3–CNN), 92.5 (s, CO–CH–CNN),
119.5 (s, C ortho, Ph–N), 123.4 (s, C para, Ph–N), 127.3 (s,
C meta, Ph–CO), 128.3 (s, C ortho, Ph–CO), 129.4 (s, C
meta, Ph–N), 131.1 (s, C para, Ph–CO), 139.6 (s, C ipso,
Ph–CO), 146.3 (s, C ipso, Ph–N), 166.3 (s, CNN), 189.2 (s,
CO). ESI-MS: found m/z 329.165 for [2b +1]+, calculated
for C22H20N2O, 328.158.
(Z)-methyl 3-(2,2-diphenylhydrazinyl)but-2-enoate, 2c:
This compound was prepared following a procedure
analogous to that described for compound 2b, but using
N,N-diphenylhydrazine hydrochloride (1.25 g, 5.50 mmol),
Et3N (0.77 mL, 5.50 mmol) and methyl 3-oxobutanoate
(0.50 mL, 4.59 mmol). Compound 2c was obtained as a
brown crystalline solid (0.952 g, 73% yield). IR (KBr, cm−
1): 3653, 3266, 3089, 3064, 3039, 3026, 3009, 2950, 2926,
2839, 2596, 2491, 2316, 2208, 2102, 2055, 1942, 1868,
1742, 1663, 1613, 1591, 1493, 1460, 1451, 1434, 1383,
1332, 1315, 1274, 1189, 1169, 1124, 1080, 1055, 1030,
1005, 934, 917, 904, 883, 789, 750, 694, 620, 540, 504,
(Z)-3-(2,2-diphenylhydrazinyl)-cyclohex-2-enone,
2f:
This compound was prepared following a procedure
analogous to that described for compound 2b, but using
N,N-diphenylhydrazine hydrochloride (1.277 g, 5.6 mmol),
Et3N (0.79 mL, 5.6 mmol) and cyclohexane-1,3-dione
(0.648 g, 5.6 mmol). Compound 2f was obtained as a
brown crystalline solid (0.559 g, 36% yield). IR (KBr, cm−
1): 3191, 2943, 1587, 1573, 1526, 1489, 1457, 1427, 1360,
1333, 1313, 1295, 1241, 1183, 1139, 1075, 1029, 995, 966,
912, 886, 860, 826, 746, 690, 625, 557, 508, 489, 461, 442,
1
432, 422, 407, 404. H NMR (CDCl3, 300 Hz): δ 1.98 (s,
3H, CH3–CNN), 3.71 (s, 3H, OCH3), 4.70, (s, 1H, CO–
CH–CNN), 7.04-7.12 (m, 2H, CH para, Ph), 7.16-7.20 (m,
4H, CH ortho, Ph), 7.30-7.36 (m, 4H, CH meta, Ph), 10.19
(s, 1H, NH). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 18.5 (s,
CH3–CNN), 50.4 (s, OCH3), 84.5 (s, CO–CH–CNN),
119.1 (s, C ortho, Ph), 123.0 (s, C para, Ph), 129.3 (s, C
meta, Ph), 146.6 (s, C ipso, Ph), 163.2 (s, CNN), 170.4 (s,
CO). ESI-MS: found m/z 283.144 for [2c +1]+, calculated
for C17H18N2O2, 282.137.
1
407. H NMR (CDCl3, 300 Hz): δ 1.80 (t, 2H, J = 6 Hz,
CH2-CH2-CH2), 2.09 (t, 2H, J = 6.3 Hz, CH2-CH2-CNN),
2.32 (t, 2H, J = 6 Hz, CO–CH2-CH2), 5.51 (s, 1H, CO–
CH–CNN), 6.93-7.03 (m, 6H, CH ortho and para, Ph), 7.17
(t, 4H, J = 8.1 Hz, CH meta, Ph), 8.95 (s, 1H, NH).
13C{1H} NMR (CDCl3, 75,47 Hz):
δ
21.8 (s,
CH2-CH2-CH2), 26.1 (s, CH2-CH2-CNN), 36.6 (s, CO–
CH2-CH2), 97.2 (s, CO–CH–CNN), 119.3 (s, C ortho, Ph),
123.0 (s, C para, Ph), 129.2 (s, C meta, Ph), 145.4 (s, C
ipso, Ph), 165.6 (s, CNN), 198.6 (s, CO). ESI-MS: found
m/z 279.150 for [2f + H]+, calculated for C18H18N2O,
278.142.
(Z)-ethyl 3-(2,2-diphenylhydrazinyl)but-2-enoate, 2d:
This compound was prepared following a procedure
analogous to that described for compound 2b, but using
N,N-diphenylhydrazine hydrochloride (1.063 g, 4.67
mmol), Et3N (0.66 mL, 4.67 mmol) and ethyl 3-
oxobutanoate (0.50 mL, 3.89 mmol). Compound 2d was
obtained as a brown crystalline solid (0.803 g, 72% yield).
IR (KBr, cm-1): 3418, 3279, 3053, 3028, 2979, 2939, 2897,
1669, 1609, 1592, 1524, 1492, 1457, 1383, 1334, 1296,
1241, 1163, 1147, 1065, 1028, 992, 93, 888, 864, 824, 790,
757, 694, 602, 539, 512, 483. 1H NMR (CDCl3, 300 Hz): δ
1.31 (t, 3H, J = 6.9 Hz, OCH2CH3), 1.96 (s, 3H, CH3–
CNN), 4.16 (c, 2H, J = 7.2 Hz, OCH2CH3), 4.67 (s, 1H,
(Z)-3-(2-methyl-2-phenylhydrazinyl)-1-phenyl-but-2-
en-1-one, 2h: This compound was prepared following a
procedure analogous to that described for compound 2b,
but using N,N-methylphenylhydrazine (0.2 mL, 2.55
mmol) and 1-phenyl-butane-1,3-dione (0.425 g, 2.55
mmol) at 55 ºC for 20 h. The resulting residue was purified
by chromatography (1:20 AcOEt / Petroleum ether as
eluent) obtaining a yellow crystalline solid identified as 2h
−
1
(0.50 g, 73% yield). IR (KBr, cm ): 2989, 1597, 1574,
7
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
1545, 1497, 1444, 1428, 1379, 1276, 1189, 1117, 1094,
1081, 988, 932, 876, 852, 821, 802, 753, 712, 674, 551,
505. 1H NMR (CDCl3, 300 Hz): δ 2.16 (s, 3H, CH3–CNN),
3.23 (s, 3H, CH3–NN), 5.84 (s, 1H, CO–CH–CNN), 6.09-
6.95 (m, 3H, CH ortho and para, Ph–N), 7.29-7.34 (m, 2H,
CH meta, Ph–N), 7.45-7.48 (m, 3H, CH meta and para,
Ph–CO), 7.94-7.97 (m, 2H, CH ortho, Ph–CO), 12.15 (s,
1H, NH). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 18.4 (s,
CH3–CNN), 42.5 (s, CH3–NN), 91.6 (s, CO–CH–CNN),
113.6 (s, C ortho, Ph–N), 120.5 (s, C para, Ph–N), 127.3 (s,
C meta, Ph–N), 128.3 (s, C meta, Ph–CO), 129.3 (s, C
ortho, Ph–CO), 131.0 (s, C para, Ph–CO), 139.7 (s, C ipso,
1312, 1279, 1244, 1221, 1186, 1149, 1114, 1096, 1031,
1014, 994, 956, 931, 879, 830, 784, 770, 753, 695, 644,
624, 615, 590, 425. 1H NMR (CDCl3, 300 Hz): δ 1.11-1.23
(m, 12H, NCH2CH3, 2k and 2k’), 1.93 (s, 3H, CH3–CNN,
2k’), 2.07 (s, 3H, CH3–CNN, 2k), 2.25, 3,01 (s, 1H, CO–
CH2–CNN, 2k’), 3.06 (s, 3H, CH3–NN, 2k’), 3.13 (s, 3H,
CH3–NN, 2k), 3.33-3.51 (m, 8H, NCH2CH3, 2k and 2k’),
4.72, (s, 1H, CO–CH–CNN, 2k), 6.83-6.92 (m, 6H, CH
ortho and para, Ph, 2k and 2k’), 7.21-7.27 (m, 2H, CH
meta, Ph, 2k and 2k’), 10.55 (s, 1H, NH, 2k). 13C{1H}
NMR (CDCl3, 75,47 Hz): δ 12.9 (s, CH3–CNN, 2k’), 14.1,
14.2, 18.6, 18.8 (s, NCH2CH3, 2k and 2k’), 23.3 (s, CH3–
Ph–CO), 150.2 (s, C ipso, Ph–N), 166.5 (s, CNN), 189.0 (s, CNN, 2k), 37.5 (s, CO–CH2–CNN, 2k’), 40.1 (s, s, CH3–
CO). ESI-MS: found m/z 267.150 for [2h +1]+, calculated
for C17H18N2O, 266.142.
NN, 2k’), 42.0-42.3 (s, NCH2CH3, 2k and 2k’), 43.9 (s,
CH3–NN, 2k), 83.2 (s, CO–CH–CNN, 2k), 113.0-115.2 (s,
C ortho, Ph, 2k and 2k’), 119.3, 119.8 (s, C para, Ph, 2k
and 2k’), 128.7-129.0 (s, C meta, Ph, 2k and 2k’), 150.8,
151.1 (s, C ipso, Ph, 2k and 2k’),160.4 (s, CNN, 2k), 167.7
(s, CNN, 2k’), 168.0 (s, CO, 2k), 169.4 (s, CO, 2k’). ESI-
MS: found m/z 262.192 for [2k +1]+, calculated for
C15H23N3O, 261.184.
(Z)-methyl-3-(2-methyl-2-phenylhydrazinyl)but-2-
enoate, 2i: This compound was prepared following a
procedure analogous to that described for compound 2b,
but using N,N-methylphenylhydrazine (0.56 mL, 4.59
mmol) and methyl 3-oxobutanoate (0.5 mL, 4.59 mmol) at
55 ºC for 20 h. The resulting residue was purified by
chromatography (1:5 AcOEt / Petroleum ether as eluent)
obtaining a brown crystalline solid identified as 2i (0.30 g,
(Z)-3-(2-methyl-2-phenylhydrazinyl)-cyclohex-2-enone,
2l: This compound was prepared following a procedure
analogous to that described for compound 2b, but using
N,N-methylphenylhydrazine (0.20 mL, 2.55 mmol) and
cyclohexane-1,3-dione (0.295 g, 2.55 mmol) at 55 ºC for
20 h. Compound 2l was obtained as an orange oil (0.290 g,
−
1
30% yield). IR (KBr, cm ): 3436, 3249, 3093, 3061, 3036,
2990, 2956, 2909, 2880, 2842, 2811, 2650, 2608, 2531,
2466, 2310, 2204, 2094, 2055, 1987, 1943, 1927, 1851,
1838, 1785, 1656, 1599, 1490, 1458, 1450, 1435, 1410,
1378, 1346, 1312, 1274, 1208, 1188, 1168, 1119, 1082,
1058, 1029, 1013, 998, 975, 933, 882, 869, 822, 787, 751,
−
1
53% yield). IR (KBr, cm ):3200, 2943, 1570, 1519, 1494,
1453, 1426, 1362, 1339, 1286, 1238, 1180, 1137, 1110,
1
1
732, 693, 647, 623, 568, 545, 515, 486, 407. H NMR
1030, 997, 967, 860, 830, 750, 690, 586, 493, 467. H
(CDCl3, 300 Hz): δ 1.98 (s, 3H, CH3–CNN), 3.16 (s, 3H,
CH3–NN), 3.70 (s, 3H, OCH3), 4.66, (s, 1H, CO–CH–
CNN), 6.90 (m, 3H, CH ortho and para, Ph), 7.30 (dt, J =
7.8 Hz, J = 1.5 Hz, 2H, CH meta, Ph), 9.65 (s, 1H, NH).
13C{1H} NMR (CDCl3, 75,47 Hz): δ 18.2 (s, CH3–CNN),
42.1 (s, CH3–NN), 50.3 (s, 1C, OCH3), 83.1 (s, CO–CH–
CNN), 113.1 (s, C ortho, Ph), 120.0 (s, C para, Ph), 129.3
(s, C meta, Ph), 150.6 (s, C ipso, Ph), 163.3 (s, CNN),
170.5 (s, CO). ESI-MS: found m/z 221.128 for [2i +1]+,
calculated for C12H16N2O2, 220.121.
NMR (CDCl3, 300 Hz): δ 1.93 (t, 2H, J = 6.3 Hz,
CH2-CH2-CH2), 2.23 (t, 2H, J = 6.6 Hz, CH2-CH2-CNN),
2.36 (sa, 2H, CO–CH2-CH2), 3.01 (s, 3H, CH3), 5.36 (s, 1H,
CO–CH–CNN), 6.73 (d, 2H, CH ortho, Ph), 6.84 (t, 1H, J
= 7.2 Hz, CH para, Ph), 7.21 (t, 4H, J = 7.8 Hz, CH meta,
Ph), 7.44 (s, 1H, NH). 13C{1H} NMR (CDCl3, 75,47 Hz): δ
21.8 (s, CH2-CH2-CH2), 26.4 (s, CH2-CH2-CNN), 36.6 (s,
CO–CH2-CH2), 39.5 (s, CH3), 97.0 (s, CO–CH–CNN),
113.1 (s, C ortho, Ph), 119.9 (s, C para, Ph), 129.1 (s, C
meta, Ph), 148.7 (s, C ipso, Ph), 164.4 (s, CNN), 198.3 (s,
CO). ESI-MS: found m/z 217.133 for [2l + H]+, calculated
for C13H16N2O, 216.126.
(Z)-ethyl 3-(2-methyl-2-phenylhydrazinyl)but-2-enoate,
2j: An excess of N,N-methylphenylhydrazine (1.13 mL,
9.37 mmol) was added to ethyl 3-oxobutanoate (0.80 mL,
6.25 mmol) and the mixture was stirred at 0 °C for 4 h and,
additionally, for 72 h at room temperature. A reddish oil
was collected and washed with diethylether (10 mL) and
(Z)-4-(2,2-dimethylhydrazinyl)pent-3-en-2-one,
2m:
This compound was prepared following a procedure
analogous to that described for compound 2b, but using
but using N,N-dimethylhydrazine (2.2 mL, 22 mmol) and
pentane-2,4-dione (1.7 mL, 22 mmol). The resulting
reddish oil was purified by cold trap distillation obtaining a
brownish oil identified as 2m (2.15 g, 69% yield). IR (KBr,
purified by column chromatography (1:5 AcOEt
/
Petroleum ether as eluent) obtaining a brownish oil
identified as 2j (1.40 g, 96% yield). IR (KBr, cm−1): 3426,
2977, 2940, 2804, 2740, 2679, 2603, 2530, 2493, 2347,
1477, 1435, 1399, 1385, 1365, 1172, 1079, 1037, 850, 806,
−
1
cm ): 3433, 3233, 3158, 2989, 2956, 2928, 2901, 2861,
2823, 2781, 2492, 2121, 1858, 1612, 1572, 1515, 1468,
1431, 1377, 1358, 1287, 1228, 1195, 1161, 1094, 1061,
1018, 980, 907, 876, 836, 731, 657, 629, 459, 431, 420,
1
458. H NMR (CDCl3, 300 Hz): δ 1.34 (t, J = 7.2 Hz, 3H,
OCH2CH3), 1.97 (s, 3H, CH3–CNN), 3.16 (s, 3H, CH3–
NN), 4.17 (c, J = 7.2 Hz, 2H, OCH2CH3), 4.66, (s, 1H,
CO–CH–CNN), 6.94 (m, 3H, CH ortho and para, Ph), 7.30
(dt, J = 7.7 Hz y J = 2.4 Hz, 2H, CH meta, Ph), 9.67 (s, 1H,
NH). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 14.2 (s,
OCH2CH3), 18.5 (s, CH3–CNN), 42.2 (s, CH3–NPh), 58.7
(s, 1C, OCH2CH3), 83.5 (s, CO–CH–CNN), 115.5 (s, C
ortho, Ph), 120.1 (s, C para, Ph), 128.9 (s, C meta, Ph),
150.7 (s, C ipso, Ph), 165.4 (s, CNN), 170.1 (s, CO). ESI-
MS: found m/z 235.144 for [2i +1]+, calculated for
C13H18N2O2, 234.137.
1
414, 411, 408, 401. H NMR (CDCl3, 300 Hz): δ 1.92 (s,
3H, CH3–CNN), 2.01 (s, 3H, CH3–CO), 2.54 (s, 6H,
(CH3)2NN), 4.85 (s, 1H, CO–CH–CN), 11.12 (s, 1H, NH).
13C{1H} NMR (CDCl3, 75,47 Hz): δ 17.8 (s, CH3–CNN),
28.4 (s, CH3–CO), 47.0 (s, (CH3)2NN), 93.2 (s, CO–CH–
CNN), 162.7 (s, CNN), 194.7 (s, CO). ESI-MS: found m/z
143.118 for [2m + H]+, calculated for C7H14N2O, 142.111.
(Z)-3-(2,2-dimethylhydrazinyl)-1-phenyl-but-2-en-1-one,
2n: This compound was prepared following a procedure
analogous to that described for compound 2b, but using
but using N,N-dimethylhydrazine (0.26 mL, 3.38 mmol)
and 3-hydroxy-1-phenyl-but-2-en-1-one (0.563 g, 3.38
mmol). The resulting brownish oil was evaporated to
dryness and was identified as a pure 2n (0.685 g, 99%
(Z)-N,N-diethyl-3-(2-methyl-2-phenylhydrazinyl)but-2-
enamide, 2k and its tautomer N,N-diethyl-3-(2-methyl-
2-phenylhydrazineylidene)butanamide,
2k’
This
tautomer mixture was prepared following a procedure
analogous to that described for compound 2j, but using
N,N-methylphenylhydrazine (0.50 mL, 3.05 mmol) and
N,N-diethyl-3-oxobutanamide (0.37 mL, 3.05 mmol) at 80
ºC for 20 h. Compound 2k and 2k’ were obtained as a
brownish oil (0.163 g, 22% yield). NMR analysis indicated
that compound 2k and 2k’ were isolated as 1:1 tautomer
−
1
yield). IR (KBr, cm ): 3059, 2990, 2956, 2860, 2823,
2781, 1595, 1573, 1543, 1486, 1464, 1444, 1425, 1374,
1319, 1288, 1221, 1177, 1160, 1090, 1068, 1051, 1027,
1014, 999, 921, 853, 804, 730, 687, 678, 618, 594, 566,
1
480, 441. H NMR (CDCl3, 300 Hz): δ 2.17 (s, 3H, CH3–
CNN), 2.60 (s, 6H, (CH3)2NN), 5.58 (s, 1H, CO–CH–CN),
7.40 (m, 3H, CH meta and para, Ph), 7.87 (m, 2H, CH
ortho, Ph), 11.75 (s, 1H, NH). 13C{1H} NMR (CDCl3,
75,47 Hz): δ 18.6 (s, CH3–CNN), 48.4 (s, (CH3)2NN), 90.1
−
1
mixture. IR (KBr, cm ): 3477, 3174, 3092, 3062, 3025,
2974, 2933, 2874, 2806, 2600, 2446, 2072, 1929, 1839,
1640, 1616, 1600, 1493, 1452, 1433, 1412, 1379, 1362,
8
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
(s, CO–CH–CNN), 127.0 (s, C ortho, Ph), 128.1 (s, C meta, MS: found m/z 365.126 for [3b +Na]+, C22H18N2O2,
Ph), 130.5 (s, C para, Ph), 140.1 (s, C ipso, Ph), 164.8 (s,
CNN), 187.7 (s, CO). ESI-MS: found m/z 205.133 for [2n
+ H]+, calculated for C12H16N2O, 204.126.
calculated for 342.137.
(E)-methyl 3-(2,2-diphenylhydrazono)-2-oxobutanoate,
3c: Starting with 0,41 mmol of compound 2c and 0,01
mmol of Mn(AcO)2. Yellow crystalline solid (0.080 g,
(Z)-3-(2,2-dimethylhydrazinyl)-cyclohex-2-enone, 2o:
This compound was prepared following a procedure
analogous to that described for compound 2b, but using
but using N,N-dimethylhydrazine (0.34 mL, 4.34 mmol)
and 3-hydroxy-cyclohex-2-enone (0.501 g, 4.34 mmol).
The resulting orange oil was evaporated to dryness and
was identified as a pure 2o (0.655 g, 99% yield). IR (KBr,
−
1
66% yield). IR (KBr, cm ): 3419, 2952, 1741, 1673, 1640,
1590, 1556, 1487, 1430, 1385, 1370, 1341, 1315, 1292,
1245, 1197, 1172, 1136, 1044, 968, 949, 902, 818, 763,
724, 699, 626, 527, 498, 411. 1H NMR (CDCl3, 300 Hz): δ
1.38 (s, 3H, CH3–CNN), 3.93 (s, 3H, OCH3), 7.15-7.18 (m,
4H, CH ortho, Ph), 7.25-7.30 (m, 2H, CH para, Ph), 7.35-
7.40 (m, 4H, , CH meta, Ph). 13C{1H} NMR (CDCl3, 75,47
Hz): δ 11.9 (s, CH3–CNN), 52.1 (s, OCH3), 123.1 (s, C
ortho, Ph), 126.5 (s, C para, Ph), 129.3 (s, C meta, Ph),
139.1 (s, CNN), 144.5 (s, C ipso, Ph), 167.8 (s, MeO–CO),
187.8 (s, CO–CO–CNN). ESI-MS: found m/z 319.105 for
−
1
cm ): 3191, 3041, 2989, 2931, 1600, 1563, 1525, 1462,
1435, 1363, 1341, 1316, 1293, 1234, 1190, 1160, 1140,
1061, 1023, 1009, 969, 914, 860, 839, 768, 686, 607, 575,
1
519, 495, 445, 432. H NMR (CDCl3, 300 Hz): δ 1.88 (q,
2H, J = 6.3 Hz, CH2-CH2-CH2), 2.24 (t, 4H, J = 6.3 Hz,
CO–CH2-CH2-CH2-CNN), 2.47 (s, 6H, (CH3)2NN), 5.52 (s, [3c +Na]+, calculated for C17H16N2O3, 296.116.
1H, CO–CH–CN), 7.00 (s, 1H, NH). 13C{1H} NMR
(CDCl3, 75,47 Hz): δ 21.9 (s, CH2-CH2-CH2), 26.9 (s,
(E)-ethyl 3-(2,2-diphenylhydrazono)-2-oxobutanoate,
CH2-CH2-CNN), 36.8 (s, (CH3)2NN), 46.4 (s, CO–
3d: Yellow crystalline solid (0.151 g, 97% yield). IR (KBr,
cm-1): 3459, 3337, 3094, 3061, 3004, 2982, 2969, 2947,
2905, 2878, 2578, 2533, 2346, 2063, 1963, 1949, 1926,
1883, 1852, 1809, 1792, 1739, 1675, 1587, 1559, 1485,
1458, 1450, 1428, 1394, 1372, 1336, 1314, 1289, 1275,
1248, 1199, 1174, 1072, 1154, 1135, 1045, 1026, 973, 956,
CH2-CH2), 95.9 (s, CO–CH–CNN), 163.9 (s, CNN), 197.4
(s, CO). ESI-MS: found m/z 155.118 for [2o + H]+,
calculated for C8H14N2O, 154.111.
General procedure for the synthesis of α,β-
dicarbonylhydrazones. The reactor (a 100 mL Fisher
1
935, 901, 872, 841, 754, 725, 697, 626, 522, 498, 414. H
Porter vessel equipped with
a
lipped heavy-wall
NMR (CDCl3, 300 Hz): δ 1.42 (t, 6H, J = 6.8 Hz,
OCH2CH3), 2.07 (s, 3H, CH3–CNN), 4.43 (c, 4H, J = 7.2
Hz, OCH2CH3), 7.18-7.21 (m, 4H, CH ortho, Ph), 7.28-
7.31 (m, 2H, CH para, Ph), 7.37-7.44 (m, 4H, CH meta,
Ph). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 12.0 (s, CH3–
CNN), 14.3 (s, OCH2CH3), 61.6 (s, OCH2CH3), 123.2 (s, C
ortho, Ph), 126.4 (s, C para, Ph), 129.3 (s, C meta, Ph),
139.2 (s, CNN), 144.5 (s, C ipso, Ph), 167.5 (s, EtO–CO),
188.1 (s, CO–CO–CNN). ESI-MS: found m/z 333.120 for
[3d +Na]+, calculated for C18H18N2O3, 310.132.
borosilicate glass tube, a stirrer flea, a stainless steel lid
sealed with a toric joint and held in place with a coupling)
was charged with Mn(AcO)2 (3.1 mg, 0.0125 mmol),
ethanol (10 mL), and the corresponding β-
carbonylenehydrazine substrate (0.5 mmol), in the
aforementioned order. The reactor was sealed with an
oxygen atmosphere (1 bar) and heated to the corresponding
temperature (60 ºC) maintaining constant stirring (600
rpm) in a thermostated oil bath for 18 h. Upon completion
the reactor was immediately cooled to -4 ºC, evaporating to
dryness by using a rotavap and the residue was then
extracted with diethyl ether (10 mL). The resulting solution
was filtered with 0.45 m nylon syringe filter, dried
(MgSO4) and cooled at -20 ºC.
(E)-3-(2,2-diphenylhydrazono)-N,N-diethyl-2-
oxobutanamide, 3e: Yellow crystalline solid (0.105 g,
−
1
62% yield). IR (KBr, cm ): 3325, 3065, 3042, 2978, 2937,
2877, 2538, 2332, 2245, 1952, 1877, 1736, 1672, 1641,
1591, 1564, 1490, 1457, 1382, 1368, 1332, 1314, 1280,
1209, 1178, 1154, 1130, 1103, 1074, 1051, 1026, 1003,
946, 912, 855, 821, 783, 752, 728, 700, 693, 646, 625, 587,
(E)-4-(2,2-diphenylhydrazono)pentane-2,3-dione,
3a:
Yellow crystalline solid (0.043 g, 31% yield). IR (KBr, cm
−
1): 3411, 3062, 3011, 2931, 2856, 2564, 1958, 1887, 1711,
499, 447, 436, 429, 424, 406, 402. H NMR (CDCl3, 300
1
1671, 1588, 1560, 1489, 1456, 1436, 1364, 1351, 1332,
1232, 1173, 1133, 1076, 1043, 1028, 1006, 969, 951, 916,
904, 888, 847, 831, 782, 765, 745, 698, 652, 594, 556, 522,
Hz): δ 1.18 (t, J = 5.9 Hz, 3H, NCH2CH3), 1.29 (t, J = 6.1
Hz, 3H, NCH2CH3) 1.41 (s, 3H, CH3–CNN), 3.25 (c, 2H,
NCH2CH3), 3.52 (c, J = 6.6 Hz, 2H, NCH2CH3), 7.18 (d, J
= 4.5 Hz, 4H, CH ortho, Ph), 7.25 (t, J = 3.6 Hz, 2H, CH
para, Ph), 7.36 (t, J = 8.1 Hz, 4H, CH meta, Ph). 13C{1H}
NMR (CDCl3, 75,47 Hz): δ 12.2, 12.9 (s, NCH2CH3), 13.8
(s, CH3–CNN), 38.3, 42.1 (s, NCH2CH3), 123.1 (s, C ortho,
Ph), 126.2 (s, C para, Ph), 129.2 (s, C meta, Ph), 140.0 (s,
CNN), 144.9 (s, C ipso, Ph), 169.1 (s, Et2N–CO), 192.2 (s,
CO–CO–CNN). ESI-MS: found m/z 338.186 for [3e +H]+,
calculated for C20H23N3O2, 337.179.
1
506, 495, 436, 419. H NMR (CDCl3, 300 Hz): δ 1.39 (s,
3H, CH3–CNN), 2.47 (s, 3H, CH3–CO), 7.12-7.15 (m, 4H,
CH ortho, Ph), 7.27 (t, J = 5.4 Hz, 2H, CH para, Ph), 7.39
(t, J = 8.1 Hz, 4H, CH meta, Ph). 13C{1H} NMR (CDCl3,
75,47 Hz): δ 12.3 (s, CH3–CNN), 27.8 (s, CH3–CO), 123.1
(s, C ortho, Ph), 126.4 (s, C para, Ph), 129.4 (s, C meta,
Ph), 139.8 (s, CH3–CNN), 144.8 (s, C ipso, Ph), 194.8 (s,
CO–CO–CNN), 205.6 (s, CH3–CO). ESI-MS: found m/z
303.110 for [3a + Na]+, calculated for C17H16N2O2,
280.121.
(E)-4-(2-methyl-2-phenylhydrazono)pentane-2,3-dione,
3g: Colorless crystalline solid (0.096 g, 91%yield). IR
−
1
(E)-3-(2,2-diphenylhydrazono)-1-phenyl-butane-1,2-
dione, 3b: The resulting residue was purified by
chromatography (1:20 AcOEt / Petroleum ether as eluent)
obtaining a brownish oil identified as 3b (0.130 g, 76%
(KBr, cm ): 3413, 3066, 2981, 2925, 2616, 2250, 1940,
1860, 1715, 1665, 1598, 1552, 1493, 1458, 1433, 1371,
1347, 1334, 1315, 1238, 1179, 1115, 1044, 1032, 997, 984,
1
956, 877, 788, 757, 694, 644, 575, 443, 428, 422, 402. H
−
1
yield). IR (KBr, cm ): 3333, 3062, 2968, 2925, 1716,
1679, 1589, 1554, 1487, 1450, 1368, 1331, 1314, 1275,
1243, 1200, 1174, 1130, 1080, 1026, 1001, 969, 946, 914,
896, 873, 818, 781, 752, 740, 730, 706, 688, 660, 624, 616,
586, 553, 521, 499, 455. 1H NMR (CDCl3, 300 Hz): δ 1.53
NMR (CDCl3, 300 Hz): δ 2.14 (s, 3H, CH3–CNN), 2.37 (s,
3H, CH3–CO), 3.69 (s, 3H, CH3–NN), 7.10 (t, J = 6.6 Hz,
1H, CH para, Ph), 7.18 (d, J = 7.8 Hz, 2H, CH ortho, Ph),
7.33 (t, J = 7.2 Hz, 2H, CH meta, Ph). 13C{1H} NMR
(CDCl3, 75,47 Hz): δ 13.1 (s, CH3–CNN), 27.8 (s, CH3–
(s, 3H, CH3–CNN), 6.96-6.99 (d, 4H, J = 7.2 Hz, CH ortho, CO), 41.9 (s, CH3–NN), 118.1 (s, C ortho, Ph), 124.2 (s, C
Ph–N), 7.18-7.31 (m, 6H, CH meta and para, Ph–N), 7.53
(t, 2H, J = 7.5 Hz, CH meta, Ph–CO), 7.63 (t, 1H, J = 7.5
Hz, CH para, Ph–CO), 7.98 (d, 2H, J = 7.2 Hz, CH ortho,
Ph–CO),. 13C{1H} NMR (CDCl3, 75,47 Hz): δ 12.3 (s,
CH3–CNN), 123.0 (s, C ortho, Ph–N), 126.4 (s, C para,
Ph–N), 128.8 (s, C meta, Ph–CO), 129.1 (s, C ortho, Ph–
CO), 129.3 (s, C meta, Ph–N), 134.0 (s, C para, Ph–CO),
141.3 (s, C ipso, Ph–CO), 144.7 (s, C ipso, Ph–N), 166.7 (s,
CNN), 195.2 (s, Ph-CO), 198.3 (s, CO–CO–CNN). ESI-
para, Ph), 129.2 (s, C meta, Ph), 137.1 (s, CNN), 147.9 (s,
C ipso, Ph), 194.7 (s, CO–CO–CNN), 205.9 (s, CH3–CO).
ESI-MS: found m/z 241.095 for [3g +Na]+, calculated for
C12H14N2O2, 218.106.
(E)-3-(2-methyl-2-phenylhydrazono)-1-phenyl-butane-
1,2-dione, 3h: yellow crystalline solid (0.100 g, 71%yield).
IR (KBr, cm−1): 1681, 1663, 1595, 1582, 1545, 1487, 1461,
9
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
1447, 1370, 1332, 1314, 1277, 1243, 1216, 1176, 1160,
1114, 1103, 1074, 1033, 1010, 1001, 944, 898, 865, 827,
794, 781, 755, 731, 705, 689, 656, 616, 596, 513, 478, 461.
1H NMR (CDCl3, 300 Hz): δ 2.33 (s, 3H, CH3–CNN), 3.69
(s, 3H, CH3–NN), 6.94 (d, 2H, J = 7.8 Hz, CH ortho, Ph–
N), 7.02 (t, 1H, J = 7.2 Hz, CH para, Ph–N), 7.19 (t, 2H, J
= 8.4 Hz, CH meta, Ph–N), 7.49 (t, 2H, J = 7.2 Hz, CH
meta, Ph–CO), 7.60 (t, 1H, J = 7.5 Hz, CH para, Ph–CO),
7.90 (d, 2H, J = 6.9Hz, CH ortho, Ph–CO). 13C{1H} NMR
(CDCl3, 75,47 Hz): δ 13.3 (s, CH3–CNN), 41.4 (s, CH3–
NN), 117.7 (s, C ortho, Ph–N), 123.9 (s, C para, Ph–N),
128.7 (s, C meta, Ph–CO), 128.9 (s, C meta, Ph–N), 129.1
(s, C ortho, Ph–CO), 133.8 (s, C para, Ph–CO), 134.2 (s, C
ipso, Ph–CO), 138.4 (s, C ipso, Ph–N), 147.6 (s, CNN),
194.9 (s, Ph–CO), 198.3 (s, CO–CO-CNN). ESI-MS:
found m/z 303.110 for [3h +Na]+, calculated for
C17H16N2O2, 280.121.
1658, 1610, 1556, 1468, 1433, 1371, 1303, 1228, 1164,
1138, 1098, 1044, 1019, 953, 917, 820, 772, 733, 452, 444,
1
431, 422, 415, 409. H NMR (CDCl3, 300 Hz): δ 2.06 (s,
3H, CH3–CNN), 2.23 (s, 3H, CH3–CO), 3.19 (s, 6H,
(CH3)2NN). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 11.6 (s,
CH3–CNN), 27.7 (s, CH3–CO), 48.3 (s, (CH3)2NN), 133.7
(s, CNN), 201.6 (s, CO–CO–CNN), 206.2 (s, CH3–CO).
ESI-MS: found m/z 157.097 for [3m + H]+, calculated for
C7H12N2O2, 156.090.
(E)-3-(2,2-dimethylhydrazinyl)-1-Phenyl-butane-1,2-
dione, 3n: The resulting residue was purified by
chromatography (1:1 AcOEt / Petroleum ether as eluent)
obtaining an orange oil identified as 3n (0.054 g, 50%). IR
−
1
(KBr, cm ): 2957, 2864, 1713, 1681, 1655, 1596, 1580,
1534, 1490, 1449, 1426, 1370, 1319, 1293, 1221, 1176,
1101, 1070, 1026, 1001, 965, 921, 883, 854, 737, 711, 688,
661, 616, 566, 536, 441. 1H NMR (CDCl3, 300 Hz): δ 2.22
(s, 3H, CH3–CNN), 3.10 (s, 6H, (CH3)2NN), 7.43 (m, 3H,
CH ortho and para, Ph), 7.80 (m, 2H, CH meta, Ph).
13C{1H} NMR (CDCl3, 75,47 Hz): δ 11.6 (s, CH3–CNN),
46.3 (s, (CH3)2NN), 128.5 (s, C ortho, Ph), 128.9 (s, C
meta, Ph), 133.4 (s, C para, Ph), 134.5 (s, C ipso, Ph),
165.0 (s, CNN), 194.4 (s, Ph–CO), 198.5 (s, CO-CO-CNN).
ESI-MS: found m/z 219.113 for [3n + H]+, calculated for
C12H14N2O2, 218.106.
(E)-methyl
3-(2-methyl-2-phenylhydrazono)-2-
oxobutanoate, 3i: Colorless crystalline solid (0.069 g.,
−
1
59% yield). IR (KBr, cm ): 3457, 3067, 3014, 2957, 2849,
1947, 1737, 1674, 1641, 1556, 1490, 1455, 1439, 1424,
1371, 1353, 1334, 1296, 1244, 1211, 1181, 1156, 1117,
1050, 1033, 1008, 957, 894, 818, 787, 747, 760, 729, 692,
1
516, 478, 410. H NMR (CDCl3, 300 Hz): δ 2.17 (s, 3H,
CH3–CNN), 3.73 (s, 3H, CH3–NN), 3.87 (s, 3H, OCH3),
7.14 (t, 3H, J = 7.8 Hz, CH para, Ph), 7.24 (m, 2H, CH
ortho, Ph), 7.34 (dt, J = 7.2 Hz y J = 1.5 Hz, 2H, CH meta,
Ph). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 12.8 (s, CH3–
CNN), 42.5 (s, CH3–NN), 51.9 (s, OCH3), 118.1 (s, C
ortho, Ph), 124.3 (s, C para, Ph), 129.1 (s, C meta, Ph),
136.2 (s, CNN), 147.9 (s, C ipso, Ph),167.9 (s, MeO–CO),
187.6 (s, CO–CO–CNN). ESI-MS: found m/z 257.090 for
[3i +Na]+, calculated for C12H14N2O3, 234.100.
(E)-3-(2,2-dimethylhydrazinyl)-cyclohexane-1,2-dione,
3o: dark brown oil (0.036 g, 43% yield). IR (KBr, cm−1):
3420, 3198, 3045, 2989, 2929, 2361, 2341, 1604, 1565,
1528, 1460, 1384, 1366, 1262, 1235, 1192, 1161, 1141,
1024, 915, 840, 801, 688, 668, 608, 575, 527, 496, 446,
1
432. H NMR (CDCl3, 300 Hz): δ 1.91 (q, 2H, J = 6 Hz,
CH2-CH2-CH2), 2.17 (m, 2H, CH2-CH2-CNN), 2.26 (t, 2H,
J = 6 Hz, CO–CH2-CH2), 2.44 (s, 6H, (CH3)2NN), 5.08,
5.54 (s, 2H, CO–C(OH)2–CNN). 13C{1H} NMR (CDCl3,
(E)-ethyl
3-(2-methyl-2-phenylhydrazono)-2-
oxobutanoate, 3j: Starting with 0,62 mmol of compound
2j and 0,016 mmol of Mn(AcO)2.The resulting residue was
purified by chromatography (1:5 AcOEt / Petroleum ether
as eluent) obtaining a colorless crystalline solid identified
75,47 Hz):
δ
20.9 (s, CH2-CH2-CH2), 26.2 (s,
CH2-CH2-CNN), 35.8 (s, (CH3)2NN), 46.0 (s, CO–
CH2-CH2), 96.7 (s, CO–C(OH)2–CNN), 161.1 (s, CNN),
196.7 (s, CO). ESI-MS: found m/z 169.097 for [3o + H]+,
calculated for C8H12N2O2, 168.090.
−
1
as 3j (0.112 g, 73% yield). IR (KBr, cm ): 3399, 1572,
1419, 1344, 1212, 1154, 1006, 1028, 956, 769, 666, 555,
1
502. H NMR (CDCl3, 300 Hz): δ 1.39 (t, J = 7.2 Hz, 3H,
Synthesis
of
the
adduct
(E)-4-(2-methyl-2-
OCH2CH3), 2.17 (s, 3H, CH3–CNN), 3.69 (s, 3H, CH3–
NN), 4.37 (c, J = 7.2 Hz, 2H, OCH2CH3), 7.13-7.38 (m, 5H,
CH, Ph). 13C{1H} NMR (CDCl3, 75,47 Hz): δ 12.8 (s,
CH3–CNN), 14.2 (s, OCH2CH3), 41.5 (s, CH3–NN), 61.4 (s,
OCH2CH3), 118.1 (s, C ortho, Ph), 124.21 (s, C para, Ph),
129.0 (s, C meta, Ph), 136.3 (s, CNN), 147.9 (s, C ipso,
Ph), 167.5 (s, EtO–CO), 187.8 (s, CO–CO–CNN). ESI-
MS: found m/z 271.106 for [2j +Na]+, calculated for
C13H16N2O3, 248.116.
phenylhydrazineylidene)-3-((2,2,6,6-
tetramethylpiperidin-1-yl)oxy)pentan-2-one, 4: To a
solution of Mn(AcO)3 (138.2 mg, 0.5 mmol) in dried
MeOH (10 mL) were added compound 2g (0.102 g, 0.5
mmol) and TEMPO (0.078 g, 0.5 mmol) under N2
atmosphere. The mixture was stirred at 60 ºC for 24 h.
After cooling to room temperature, the mixture was
concentrated to dryness and extracted with diethylether.
The organic solution was filtered and concentrated under
reduced pressure. The product was purified by
chromatography (40:3 petroleum ether/EtOAc). Compound
4 was obtained as a yellow orange solid (0.81 g, 45%
(E)-N,N-diethyl-3-(2-methyl-2-phenylhydrazono)-2-
oxobutanamide, 3k: Colorless crystalline solid (0.063 g,
−
−
1
1
46% yield). IR (KBr, cm ): 3421, 3061, 2988, 2941, 2455,
1950, 1864, 1796, 1670, 1636, 1598, 1587, 1557, 1492,
1478, 1463, 1448, 1440, 1383, 1369, 1337, 1316, 1287,
1232, 1186, 1154, 1118, 1079, 1050, 1033, 1012, 987, 966,
yield). IR (KBr, cm ): 2926, 2854, 1719, 1671, 1598,
1555, 1493, 1462, 1375, 1361, 1278, 1261, 1239, 1178,
1133, 1065, 1044, 1026, 994, 957, 877, 787, 752, 734, 692,
1
645, 596, 573, 520. H NMR (CDCl3, 500 Hz, at 10 ºC): δ
1
947, 897, 846, 787, 758, 732, 691, 640, 596, 516, 429. H
0.92-1.64 (m, 18H, TEMPO), 2.04 (s, 3H, CH3–CNN),
2.38 (s, 3H, CH3–CO), 3.11 (s, 3H, CH3–NN), 5.27, (s, 1H,
CO–CH–CNN), 7.00 (d, 3H, J = 6.9 Hz, CH ortho and
para, Ph), 7.35 (t, J = 7.8 Hz, 2H, CH meta, Ph). 13C{1H}
NMR (CDCl3, 75,47 Hz): δ 13.8 (s, CH3–CNN), 16.0 (s,
CH2, TEMPO), 26.7 (s, CH3–CO), 31.7, 33.0 (s, CH3,
TEMPO), 39.1 (s, CH2, TEMPO), 40.8 (s, 1C, CH3-NN),
58.5, 59.3 (s, C, TEMPO), 95.4 (s, CO–CH–CNN), 114.7
NMR (CDCl3, 300 Hz): δ 1.11 (t, 3H, J = 7.2 Hz,
NCH2CH3), 1.25 (t, 3H, J = 7.2 Hz, NCH2CH3), 2.22 (s,
3H, CH3–CNN), 3.18 (c, 2H, J = 6.9 Hz, NCH2CH3), 3.51
(c, 2H, J = 6.9 Hz, NCH2CH3), 3.71 (s, 3H, CH3–NN), 7.07
(t, 1H, J = 1.5 Hz, CH para, Ph), 7.24-7.33 (m, 4H, CH
ortho and meta, Ph). 13C{1H} NMR (CDCl3, 75,47 Hz): δ
12.8, 13.1 (s, NCH2CH3), 13.7 (s, CH3–CNN), 38.2 (s,
CH3–NN), 41.3, 42.0 (s, NCH2CH3), 117.6 (s, C ortho, Ph), (s, C ortho, Ph), 119.5 (s, C para, Ph), 127.8 (s, C meta,
123.6 (s, C para, Ph), 128.9 (s, C meta, Ph), 137.5 (s,
CNN), 148.1 (s, C ipso, Ph), 169.2 (s, Et2N–CO), 192.0 (s,
CO–CO–CNN). ESI-MS: found m/z 298.152 for [3k
+Na]+, calculated for C15H21N3O2, 275.163.
Ph), 150.1 (s, C ipso, Ph), 164.7 (s, CH3–CNN), 204.8 (s,
Me–CO). ESI-MS: found m/z 382.25 for [4 +Na]+,
calculated for C21H33N3O2, 359.24).
X-ray crystallography. Crystals of suitable size for X-ray
diffraction analysis of 2c, 2i, 3a, 3c, 3d, 3i and 3k were
coated with dry perfluoropolyether and mounted on glass
fibres and fixed in a cold nitrogen stream (T = 213 K) to
the goniometer head. Data collection were performed on a
Bruker-Nonius X8Apex-II CCD diffractometer, using
monochromatic radiation λ(Mo Kα) = 0.71073 Å, by means
(E)-4-(2,2-dimethylhydrazono)pentane-2,3-dione, 3m:
The resulting dark orange oil contains the started material
2m. Attempts of purification by chromatography failed due
to the decomposition of product in the silica column. Yield
was calculated by NMR integration (38% yield). IR (KBr,
−
1
cm ): 3417, 2988, 2958, 2928, 2862, 2784, 2244, 1711,
10
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
of ω and φ scans with a width of 0.50 degree. The data
were reduced (SAINT)[50] and corrected for absorption
effects by the multi-scan method (SADABS).[51,52] The
[10] X. Fan, Y. He, X. Zhang, S. Guo, Y. Wang,
Tetrahedron 2011, 67, 6369–6374.
structures were solved by direct methods (SIR-2002[53]
)
[11] Y. Yang, Y. Liu, Y. Jiang, Y. Zhang, D. A. Vicic, J.
Org. Chem. 2015, 80, 6639–6648.
and refined against all F2 data by full-matrix least-squares
2
techniques (SHELXL-2016/6)[54,55] minimizing w[Fo -Fc2]2.
All non-hydrogen atoms were refined anisotropically. The
hydrogen atoms were included from calculated positions
and refined riding on their respective carbon atoms with
isotropic displacement parameters. A summary of cell
parameters, data collection, structure solution, and
refinement for these seven crystal structures are given in
the Supplementary Information (ESI). CCDC 1836191-
1836197 contain the supplementary crystallographic data
for this paper. The corresponding crystallographic data
were deposited with the Cambridge Crystallographic Data
Centre as supplementary publications. The data can be
[12] A. Gonzalez-de-Castro, C. M. Robertson, J. Xiao, J.
Am. Chem. Soc. 2014, 136, 8350–8360.
[13] Y.-F. Liang, N. Jiao, Acc. Chem. Res. 2017, 50,
1640–1653.
[14] S. S. Stahl, Science. 2005, 309, 1824–1826.
[15] M. Costas, ChemCatChem 2012, 4, 175–176.
obtained
free
of
charge
via
[16] K. Schröder, B. Join, A. J. Amali, K. Junge, X. Ribas,
M. Costas, M. Beller, Angew. Chem. Int. Ed. 2011, 50,
1425–1429.
www.ccdc.ac.uk/data.request/cif.
Computational Details. The electronic structure and
geometries of compounds 2 and 3 and intermediates Bg
and Cg were computed using density functional theory at
the B3LYP level,[56,57] using the 6-311+G** basis set for
all the atoms. Molecular geometries of the compounds 2c,i
and 3a,c,d,i,k were optimised starting from the
crystallographic coordinates. Frequency calculations were
carried out at the same level of theory to identify all of the
stationary points as transition states (one imaginary
frequency, TS1 and TS2) or as minima (zero imaginary
frequencies) and to provide the thermal correction to free
energies at 298.15 K and 1 atm. The DFT calculations
were performed using the Gaussian 09 suite of
programs.[58] Coordinates of all optimised compounds are
reported in the Supporting Information.
[17] A. E. King, L. M. Huffman, A. Casitas, M. Costas, X.
Ribas, S. S. Stahl, J. Am. Chem. Soc. 2010, 132,
12068–12073.
[18] D. Wang, A. B. Weinstein, P. B. White, S. S. Stahl,
Chem. Rev. 2018, 118, 2636–2679.
[19] G. E. Benitez-Medina, M. Amézquita-Valencia, A.
Cabrera, P. Sharma, ChemCatChem 2017, 9, 1450–
1460.
[20] S. Samai, G. C. Nandi, P. Singh, M. Singh,
Tetrahedron 2009, 65, 10155–10161.
[21] P. Hoyos, J.-V. Sinisterra, F. Molinari, A. R.
Alcꢁntara, P. Domꢂnguez de Marꢂa, Acc. Chem. Res.
2010, 43, 288–299.
Acknowledgements
Financial support from the Junta de Andalucía (Proyecto de
Excelencia FQM-7079) and Universidad de Sevilla (VI Plan
Propio) is gratefully acknowledged. We thank the Centro de
Servicios de Informática y Redes de Comunicaciones (CSIRC),
Universidad de Granada, for providing the computing time.
[22] I. V. Pimkov, B. Serli-Mitasev, A. A. Peterson, S. C.
Ratvasky, B. Hammann, P. Basu, Chem. Eur. J. 2015,
21, 17057–17072.
[23] C. G. Goodman, M. M. Walker, J. S. Johnson, J. Am.
Chem. Soc. 2015, 137, 122–125.
References
[24] Z. Wu, F. Li, J. Wang, Angew. Chem. Int. Ed. 2015,
54, 1629–1633.
[1]J.-E. Bꢀckvall, Modern Oxidation Methods, 2nd
Edition, Wiley-VCH, 2010.
[25] F. Dayer, H. L. Dao, H. Gold, H. Rodé-Gowal, H.
Dahn, Helv. Chim. Acta 1974, 57, 2201–2209.
[2] X. Liu, Y. Ryabenkova, M. Conte, Phys. Chem. Chem.
Phys. 2015, 17, 715–731.
[26] A. Duschek, S. F. Kirsch, Chem. Eur. J. 2009, 15,
10713–10717.
[3] I. Hermans, E. S. Spier, U. Neuenschwander, N. Turrà,
A. Baiker, Top. Catal. 2009, 52, 1162–1174.
[27] M. J. Batchelor, R. J. Gillespie, J. M. C. Golec, C. J.
R. Hedgecock, Tetrahedron Lett. 1993, 34, 167–170.
[4] K. Park, L. Tsou, A. Hamilton, Synthesis 2006, 3617–
3620.
[28] A. Sivan, A. Deepthi, Tetrahedron Lett. 2014, 55,
1890–1893.
[5] C. Qi, H. Jiang, L. Huang, Z. Chen, H. Chen, Synthesis
2011, 387–396.
[29] X. Han, T. Lei, X.-L. Yang, L.-M. Zhao, B. Chen, C.-
H. Tung, L.-Z. Wu, Tetrahedron Lett. 2017, 58, 1770–
1774.
[6] L. Ren, L. Wang, Y. Lv, G. Li, S. Gao, Org. Lett. 2015,
17, 2078–2081.
[30] P.-J. Zhou, C.-K. Li, S.-F. Zhou, A. Shoberu, J.-P.
[7] C. Deville, S. K. Padamati, J. Sundberg, V. McKee, W.
R. Browne, C. J. McKenzie, Angew. Chem. Int. Ed.
2016, 55, 545–549.
Zou, Org. Biomol. Chem. 2017, 15, 2629–2637.
[31] C. Zhang, X. Wang, N. Jiao, Synlett 2014, 25, 1458–
1460.
[8] S. E. Allen, R. R. Walvoord, R. Padilla-Salinas, M. C.
Kozlowski, Chem. Rev. 2013, 113, 6234–6458.
[32] L. Huang, K. Cheng, B. Yao, Y. Xie, Y. Zhang, J.
Org. Chem. 2011, 76, 5732–5737.
[9] J. De Houwer, K. Abbaspour Tehrani, B. U. W. Maes,
Angew. Chem. Int. Ed. 2012, 51, 2745–2748.
11
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
[33] M. Á. Gaona, F. Montilla, E. Álvarez, A. Galindo,
[58] Gaussian 09, Revision B.01, M. J. Frisch, G. W.
Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J.
R. Cheeseman, G. Scalmani, V. Barone, G. A.
Petersson, H. Nakatsuji, X. Li, M. Caricato, A.
Marenich, J. Bloino, B. G. Janesko, R. Gomperts, B.
Mennucci, H. P. Hratchian, J. V. Ortiz, A. F. Izmaylov,
J. L. Sonnenberg, D. Williams-Young, F. Ding, F.
Lipparini, F. Egidi, J. Goings, B. Peng, A. Petrone, T.
Henderson, D. Ranasinghe, V. G. Zakrzewski, J. Gao,
N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara, K.
Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, K.
Throssell, J. A. Montgomery, Jr., J. E. Peralta, F.
Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N.
Kudin, V. N. Staroverov, T. Keith, R. Kobayashi, J.
Normand, K. Raghavachari, A. Rendell, J. C. Burant, S.
S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam, M.
Klene, C. Adamo, R. Cammi, J. W. Ochterski, R. L.
Martin, K. Morokuma, O. Farkas, J. B. Foresman, and
D. J. Fox, Gaussian, Inc., Wallingford CT, 2010.
Dalton Trans. 2015, 44, 6516–6525.
[34] N. A. Domnin, S. I. Yakimovich, Zhurnal Org.
Khimii 1965, 1, 658–666.
[35] V. A. Yakimovich, S. I.; Khrustalev, Zhurnal Org.
Khimii 1975, 11, 1386–92.
[36] G. O. Dudek, G. P. Volpp, J. Am. Chem. Soc. 1963,
85, 2697–2702.
[37] I. S. Ahuja, R. Singh, G. L. Yadava, J. Mol. Struct.
1981, 74, 143–151.
[38] N. Saravanan, P. Selvam, Acta Crystallogr. Sect. E
Struct. Reports Online 2014, 70, m326–m327.
[39] M. Schämann, H. J. Schäfer, Synlett 2004, 1601–
1603.
[40] H. Liu, W. Feng, C. W. Kee, Y. Zhao, D. Leow, Y.
Pan, C.-H. Tan, Green Chem. 2010, 12, 953.
[41] Z.-L. Wang, X.-L. An, L.-S. Ge, J.-H. Jin, X. Luo,
W.-P. Deng, Tetrahedron 2014, 70, 3788–3792.
[42] X. Luo, Z.-L. Wang, J.-H. Jin, X.-L. An, Z. Shen, W.-
P. Deng, Tetrahedron 2014, 70, 8226–8230.
[43] J. F. Larrow, E. N. Jacobsen, Y. Gao, Y. Hong, X.
Nie, C. M. Zepp, J. Org. Chem. 1994, 59, 1939–1942.
[44] M. K. Coggins, L. M. Brines, J. A. Kovacs, Inorg.
Chem. 2013, 52, 12383–12393.
[45] D. B. Rice, A. A. Massie, T. A. Jackson, Acc. Chem.
Res. 2017, 50, 2706-2717.
[46] M. H. V. Huynh, T. J. Meyer, Chem. Rev. 2007, 107,
5004–5064.
[47] D. B. Rice, A. A. Massie, T. A. Jackson, Acc. Chem.
Res. 2017, 50, 2706–2717.
[48] B. B. Snider, Chem. Rev. 1996, 96, 339–364.
[49] B. B. Snider, Tetrahedron 2009, 65, 10738–10744.
[50] Bruker, SAINT. APEX2 2007, Bruker AXS Inc.,
Madison, Wisconsin, USA.
[51] G. M. Sheldrick, SADABS, Programs Scaling Absorpt.
Correct. Area Detect. Data 1997, University of
Göttingen: Göttingen, Germany.
[52] Bruker, SADABS. APEX2 2007, Bruker AXS Inc.,
Madison, Wisconsin, USA.
[53] M. C. Burla, M. Camalli, B. Carrozzini, G. L.
Cascarano, C. Giacovazzo, G. Polidori, R. Spagna, J.
Appl. Crystallogr. 2003, 36, 1103–1103.
[54] G. M. Sheldrick, Acta Crystallogr. Sect. A Found.
Crystallogr. 2008, 64, 112–122.
[55] G. M. Sheldrick, Acta Crystallogr. Sect. C Struct.
Chem. 2015, 71, 3–8.
[56] A. D. Becke, J. Chem. Phys. 1993, 98, 5648–5652.
[57] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B 1988, 37,
785–789.
12
This article is protected by copyright. All rights reserved.

10.1002/adsc.201800601
Advanced Synthesis & Catalysis
FULL PAPER
Synthesis of ,β-dicarbonylhydrazones by aerobic
manganese-catalysed oxidation.
Adv. Synth. Catal. Year, Volume, Page – Page
Carlos J. Carrasco, Francisco Montilla,* Eleuterio
Álvarez, and Agustín Galindo*
13
This article is protected by copyright. All rights reserved.