Design and synthesis of donor-acceptor stenhouse adducts: A visible light photoswitch derived from furfural

Article abstract of DOI:10.1021/jo502206g

The development of an easily synthesized, modular, and tunable organic photoswitch that responds to visible light has been a long-standing pursuit. Herein we provide a detailed account of the design and synthesis of a new class of photochromes based on fu

Full text of DOI:10.1021/jo502206g

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Design and Synthesis of Donor−Acceptor Stenhouse Adducts:
A Visible Light Photoswitch Derived from Furfural
Sameh Helmy, Saemi Oh, Frank A. Leibfarth, Craig J. Hawker, and Javier Read de Alaniz*,†
†
†
†
†,‡
†
‡
Department of Chemistry and Biochemistry and Materials Department, Materials Research Laboratory, University of California,
Santa Barbara, California 93106, United States
*
S Supporting Information
ABSTRACT: The development of an easily synthesized,
modular, and tunable organic photoswitch that responds to
visible light has been a long-standing pursuit. Herein we provide a
detailed account of the design and synthesis of a new class of
photochromes based on furfural, termed donor−acceptor Sten-
house adducts (DASAs). A wide variety of these derivatives are
easily prepared from commercially available starting materials, and
their photophysical properties are shown to be dependent on the
substituents of the push−pull system. Analysis of the switching
behavior provides conditions to access the two structural isomers
of the DASAs, reversibly switch between them, and use their
unique solubility behavior to provide dynamic phase-transfer
materials. Overall, these negative photochromes respond to visible light and heat and display an unprecedented level of structural
modularity and tunabilty.
INTRODUCTION
furfural undergoes ring opening to give stable, intensely colored
salts whose structure, five-carbon cyanine dyes with an OH
■
In recent decades, significant effort has been devoted to the
chemistry of organic photochromic systems. Their ability to
undergo reversible spectral and physical property changes has
group at the second carbon atom, was established by Schiff in
8
1
887 (Figure 1A). Initial imine/iminium formation between
1
furfural and the aniline activates the furan nucleus to
nucleophilic attack, which then leads to ring opening of furan
and formation of the Stenhouse salt. Nearly a century later, in
led to applications ranging from energy production, chemical
2
3
4,5
sensing, and molecular actuators to biological systems. The
driving force for this focus is the abundant and versatile nature
of light as a stimulus which enables both temporal and spatial
resolution.
1
982, Honda disclosed the visible light mediated negative
9
photochromism of Stenhouse salts (Figure 1B). Although the
mechanism and product of the photochromic reaction was not
reported, the enolic OH group was determined to be critical for
the photobleaching−thermal recoloration process since the
parent cyanine dyes with no OH group (obtained by the Zincke
ring opening of pyridinium salts) do not display these
Recently, we reported a new class of T-type organic
photochromic molecules (Scheme 1) that operate using visible
6
7
light, termed donor−acceptor Stenhouse adducts (DASAs).
The synthesis of these organic photoswitches can be conducted
on large scale under simple reaction conditions starting from
furfural, a commodity chemical derived from nonedible
biomass. In our initial communication, we focused on the
properties and application of this new class of organic
photochromic molecules. Herein we provide a detailed report
on our synthetic efforts in this area and describe a range of
additional properties for these compounds.
10
properties. In Honda’s report, the photobleaching-thermal
recoloration process was strongly dependent on the concen-
tration of added acid, and in the presence of 100 equiv of HCl
photobleaching did not occur. This result is consistent with
related studies on Stenhouse salts by Lewis and Mulquiney,
even though they did not study the photochromic properties of
11
these systems. In the Lewis study, treatment of the Stenhouse
salts with base only gave the corresponding colorless
During the initial design stage, we established three criteria
for an ideal new class of organic photochromic material that
helped guide our discovery efforts: (1) intrinsic activation by
visible light, (2) significant change in spectral absorption,
solubility, and volume, and (3) facile synthetic access,
modularity and tunability (Scheme 1).
A number of important contributions helped us establish the
basis for the discovery of DASAs as a photoswitching platform.
In 1870, Stenhouse discovered that in the presence of 2 equiv
of a primary or secondary aniline and 1 equiv of protic acid
11a
cyclopentenone adducts (Figure 1C).
Further, in 2000,
Safar and co-workers reported a preliminary study on the
rearrangement of 5-(furan-2-ylmethylene-)-2,2-dimethyl-1,3-
dioxane-4,6-dione 6 with cyclic secondary aliphatic amines
12
(
Figure 1D). In contrast to Stenhouse’s work, this system
Received: September 29, 2014
©
XXXX American Chemical Society
A
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Scheme 1. Organic Photochromic Materials: Design, Synthesis, and Properties
Figure 1. (A) Stenhouse’s ring opening of furfural by aniline and protic acid, (B) photochromism of Stenhouse salts examined by Honda, (C) Lewis
and Mulquiney’s base-mediated cyclization of Stenhouse salts, (D) Safar’s secondary amine ring opening and rearrangement of activated furans, (E)
this work: photochromic donor−acceptor Stenhouse adducts.
B
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exploited the electron-withdrawing nature of the cyclic
dicarbonyl to impart the same result as imine/iminium
activation. Interestingly, reaction of furan 6 with morpholine
or piperidine in a 2:1 or 1:1 molar ratio resulted in a mixture of
two compounds, the Stenhouse-based adduct 8 and the
corresponding cyclopentenone 9. All attempts to separate this
mixture were unsuccessful; however, treatment of this mixture
with excess HBr gave exclusively the cyclopentenone hydro-
bromide 10, and presumably the equilibrium was driven to the
product by precipitation of the salt.
95% yield with filtration as the only purification necessary
(entry 7). In direct contrast, the use of other solvents required
heating to 50 °C and resulted in lower yields (entries 5 and 6)
or inseparable mixtures of Stenhouse adduct 8 and cyclo-
pentenone 9 (entries 1−4). While the addition of Lewis acids
or bases such as dysprosium triflate or DABCO increased
yields, these conditions also produced mixtures of 8 and 9
(entries 2 and 3).
With optimized conditions for the selective formation and
isolation of the Stenhouse-based adduct 8, we next proceeded
to evaluate the generality of this process with a range of amines
(Figure 2). We found that a broad array of secondary aliphatic
Based on these reports and our interest in the cascade
13
rearrangements of furylcarbinols, we hypothesized that the
photochromic behavior observed by Honda was due to a
reversible interconversion between the open Stenhouse salt and
the closed 4,5-aminocyclopentenone. Combined, these studies
also suggest that the ability to tune and control the process by
which the open Stenhouse adduct and the closed cyclo-
pentenone adduct interconvert is dependent on the sub-
stituents of the push−pull system derived from the amine ring
opening of furfural or its derivatives. With these considerations
in mind, the Stenhouse-based adducts with a general structure
of 13 were selected for initial studies (Figure 1E).
RESULTS AND DISCUSSION
■
Synthesis. At the outset, we sought to develop optimal
conditions, compatible with a diverse range of secondary
aliphatic amines, for the selective formation of the colored
triene Stenhouse adduct 8 without concomitant generation of
the cyclopentenone 9. The optimal conditions were initially
identified using pyrrolidine (Table 1). Reacting an equimolar
ratio of furylidene−Meldrum’s acid 6 and pyrrolidine in
tetrahydrofuran provided the desired Stenhouse adduct 8 in
Table 1. Optimization of Reaction Conditions for the
Selective Formation of Stenhouse-Based Adducts (DASAs)
a
a
Figure 2. Synthesis of Meldrum’s acid derived DASAs. Isolated yields.
amines were competent reaction partners, including both cyclic
and acyclic amines, while secondary aniline derivatives also led
to ring opened triene products, albeit in diminished yield
(
22%). Unfortunately, reaction of 6 with primary anilines and
primary aliphatic amines resulted in decomposition.
With these results in hand, we then sought to determine if
other active methylene compounds could effectively activate
14
the furan ring toward ring opening. To this end, the
substrates outlined in Scheme 2 were prepared by Knoevenagel
condensation with furfural, followed by treatment with
diethylamine. To our gratification, the reactions provided the
anticipated highly colored crystalline trienes 34 and 36 in 85%
and 87% yield, respectively. Interestingly, the use of 1,1-
dicyanomethylene-3-indanone and 1,3-bis(dicyanomethylene)-
indan did not produce the desired triene, instead giving the
expanded ring dihydroindenopyridine carbonitrile derivatives
b
entry
1
solvent
temp (°C)
time (min)
product
yield (%)
c
MeCN
MeCN
MeCN
MeOH
50
50
50
50
23
50
23
60
60
60
30
60
30
10
8 + 9
8 + 9
8 + 9
8 + 9
8
60
d
c
2
70
e
c
3
80
c
4
5
6
7
80
CH Cl2
50
50
95
2
3
8 and 40, which upon standing oxidize to the pyridine
PhMe
8
15
adduct.
THF
8
Of these activating groups, we chose to further evaluate the
scope of the furan ring opening with 1,3-dimethylbarbituric acid
activated furan (33) and a range of secondary amines. We were
particularly attracted to 1,3-disubstituted barbituric acids, as
these moieties are readily prepared and the nitrogen
a
Activated furan 6 (1 equiv) and pyrrolidine 7 (1 equiv) were
sequentially added to the solvent and stirred at the temperature
b
c
d
indicated. Isolated yields. Inseparable mixture of 8 and 9. 10 mol %
of dysprosium triflate added. 10 mol % of DABCO added.
e
C
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Scheme 2. Investigation of Furan Activating Groups for the
Synthesis of DASAs
Figure 3. Synthesis of 1,3-dimethylbarbituric acid derived DASAs.
a
b
Isolated yields. NR: no reaction.
substituents provide a functional group handle to further tailor
the acceptor group to specific applications. We were pleased to
find that the desired Stenhouse adducts were formed in good
yield and had nearly equal scope as the Meldrum’s acid
derivatives with respect to the compatibility of the amine
nucleophile with few exceptions. In the case of morpholine
(
44) and phenylpiperazine (45) decomposition of 33 is
observed, whereas for isoindoline (55), dibenzylamine (56),
and N-methylaniline (57) the starting material is recovered
(
Figure 3).
To probe the potential diversity of substituents on the
barbituric acid group and to provide evidence that the N-group
could serve as a functional handle for the incorporation of these
molecules into materials, we prepared six 1,3-disubstituted
barbituric acids with various alkyl and aryl substituents. After
condensation with furfural, reaction with diethylamine resulted
in ring opening to give the anticipated colored trienes in high
yield (Figure 4).
Figure 4. Synthesis of 1,3-disubstituted barbituric acid derived DASAs.
Scheme 3. One-Pot “On Water” Synthesis of DASAs
In terms of synthetic ease, it is worth noting that the two-step
synthesis of the organic photochromic molecules can be
achieved in a one-pot fashion “on water” without affecting yield.
As shown in Scheme 3, on-water Knoevenagel condensation
between furfural and either Meldrum’s acid or 1,3-dimethyl-
16
barbituric acid is complete within 2 h. Direct addition of the
amine nucleophile results in formation of the Stenhouse
adduct, which then can be isolated by extraction with
dichloromethane (see the Supporting Information for full
experimental details). The facile nature of this process further
highlights the practicality and user-friendly protocol to access
these novel organic photochromic materials. Of greater
importance for the widespread use of these materials is the
observation that these highly colored Stenhouse adducts are
benchtop-stable, crystalline solids that can be stored without
D
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precaution over extended periods of time. Significantly, we have
observed no solid-state photochromism or decomposition of
products stored under ambient conditions for over 2 years.
With straightforward access to the stable, highly colored
triene adducts, we sought to develop conditions to isolate and
characterize the metastable cyclopentenone adduct. Although
the stability of the cyclopentenone adduct is highly dependent
on the nature of the secondary amine and the acceptor group,
we have found that photoisomerization in polar protic solvents
provides access to the closed form for a number of organic
photochromic molecules studied. For example, subjecting
methanolic suspensions of Stenhouse adducts such as 8 to
visible light irradiation results in the formation of the
corresponding zwitterionic cyclopentenone. As shown in Figure
5, adducts were converted to their colorless cyclopentenone
isomer in excellent yields. Importantly, this mild procedure
allows for isolation of these materials without the use of
12
concentrated HBr, previously developed by Safar. It is also
important to note that a subset of the triene adducts
synthesized do not undergo photoisomerization in methanol
or toluene. These include adducts derived from amines bearing
two benzylic carbons, isoindoline and dibenzylamine (30 and
3
1), or from amines bearing an electron-withdrawing group,
proline methyl ester (21 and 47). Further, the Stenhouse
adducts derived from acceptors other than Meldrum’s acid or
1,3-disubstituted barbituric acids (namely indan-1,3-dione 36)
also fail to exhibit photoisomerization. Future studies to better
understand these effects are ongoing in our laboratory.
Negative Photochromism and Related Properties.
With efficient access to a range of Stenhouse-based triene
derivatives, the properties of these materials were examined
with the diethyl amine adducts 22, 34, and 36 as model
6
systems. During our initial investigations, we were encouraged
by the ability to tune the absorption of the triene by modifying
the acceptor group. Of note, the choice of amine donor does
not affect the λmax of the Stenhouse-based complexes studied to
date. In toluene, all DASAs derived from Meldrum’s acid have a
λmax centered at 545 nm, from 1,3-disubstituted barbituric acids
at 570 nm and from 1,3-indanedione at 600 nm (Figure 6). We
have found that these trienes display appreciable solvatochrom-
ism similar to other merocyanine-type materials (see the
17
Supporting Information).
The unidirectional conversion of the colored triene 22 to its
colorless zwitterionic cyclopentenone isomer 73 can be
monitored using NMR spectroscopy (Figure 7A). Irradiating
a solution of 22 in deuterated methanol with a standard
incandescent bulb or hand-held fluorescent lamp leads to a
decrease in the NMR resonances attributable to 22 and an
increase in those for 73 over the course of 4 h. This process was
further examined by UV−vis spectroscopy for 34 in methanol
a
b
Figure 5. Photoisomerization of select DASAs. Isolated yields. NR:
no reaction.
(
Figure 7B). Similarly, visible light irradiation produces a
obenzene), but photoisomerization to the cyclopentenone does
not occur. For reversible photocyclization of the triene to
cyclopentenone with thermal reversion of the cyclopentenone
back to the triene, aromatic solvents (toluene, benzene, or
xylenes) are ideal. While the difference in the rate of
photocyclization for 22 vs 34 is negligible, it should be noted
that adducts derived from 1,3-dimethylbarbituric acid undergo
thermal reversion nearly twice as fast as those derived from
decrease in the absorption of 34 as it cyclizes to 78 over 50
1
8
min.
The reversible conversion between the colored triene and the
colorless cyclopentenone adduct is most dramatically effected
19
by solvent (Figure 8A). This is similar to spiropyran and
2
0
diarylethene systems, which have also been shown to be
highly solvent dependent. In protic solvents (methanol or
water), the colored triene can be triggered by visible light and
converted into the colorless zwitterionic cyclopentenone form;
however, thermal reversion to the triene does not occur. In
contrast, thermal reversion to the colored triene form is facile in
halogenated solvents (dichloromethane, chloroform, or chlor-
21
Meldrum’s acid (Figure 8B).
Intrigued by the solution-state behavior of our DASA
materials, we reasoned that these compounds could engage in
dynamic phase transfer. If true, this enables applications of
22
these compounds as visible light activated phase-transfer tags.
E
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Figure 6. Absorption spectra of 22, 34, and 36 in toluene.
1
Figure 7. (A) The conversion of 22 to 73 by H NMR in CD OD over 4 h. (B) Absorption spectra of 34 to 78 on irradiation with visible light (λ =
3
570 nm) in methanol. (C) Expanded view of absorption spectra between 250−280 nm.
To probe the potential of this avenue, we layered toluene
solutions of Meldrum’s acid derived adducts 22, 24, and 26
over water (Figure 9). Upon irradiation of these biphasic
systems with visible light, the DASAs were observed to cyclize
with transfer of the DASA to the aqueous layer being quantified
by UV−vis and NMR spectroscopy. We found that the amine
donor plays a dramatic role in the efficacy of transfer to the
aqueous phase. Employing short alkyl chain amine donors
(derivatives 22 and 24) results in near quantitative transfer of
the DASA to the aqueous phase. Conversely, a long alkyl chain
donor (derivative 26) results in DASA cyclization; however,
this derivative fails to transfer to the aqueous phase. Efforts to
F
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Figure 8. (A) Solution-state switching behavior of DASAs. (B) In situ kinetic plot of the switching cycle of 22 and 34 in PhMe, monitored at λmax of
45 and 570 nm, respectively.
5
Figure 9. Schematic representation of DASA dynamic phase transfer
and results.
thermally revert the cyclopentenone to the triene and transfer
the adduct from the aqueous layer back to the aromatic organic
layer were unsuccessful. However, separation of the resultant
aqueous solution and extraction with DCM enabled recovery of
the triene forms of derivatives 22 and 26 in 10% and
quantitative yield, respectively, again highlighting the critical
role of the amine donor in this process. Application of this
procedure toward catalyst separation and recycling are
underway in our laboratory and will be reported in due course.
Finally, further structural characterization of the two isomeric
DASA states was provided by single-crystal X-ray diffraction,
which revealed the triene form to be a conjugated, linear,
hydrophobic material with an amine “donor” and a 1,3-
dicarbonyl “acceptor”. Our assignment of the cyclopentenone
form as a zwitterion comes from the observation that these
materials are water-soluble and further from bond length
measurements in their crystal structures. We have found that
one of the ester (or amide) functionalities in the 1,3-dicarbonyl
moiety displays bond lengths more appropriate for a β-enolic
ester (or amide) than a β-dicarbonyl (see the Supporting
Information for further details). The large volume change these
materials exhibit upon switching is clearly evident in their
crystal structures (Figure 10). Atomic distance measurements
identify a 52% molecular contraction of the DASA upon
switching as measured from the nitrogen donor to the carbon at
the 5 position of the acceptor (7.34/7.40 Å for the open
derivative, 3.55/3.53 Å for the closed). This distance is
significantly greater than that observed for other privileged
photoswitches whose molecular contraction has been exploited
Figure 10. ORTEP renderings of 22 and 73 (top) and 34 and 78
bottom) (distances in angstroms, 50% probability ellipsoids,
hydrogen atoms omitted for clarity).
(
CONCLUSION
■
In summary, we have developed general conditions for the ring
opening of furfural derivatives activated with cyclic β-
dicarbonyls by a wide variety of secondary amines to provide
1
-dicarbonylmethylene-2-hydroxy-5-(dialkylamino)pentadienes.
This strategy provides unprecedented synthetic modularity and
tunability in the preparation of visible light activated photo-
switches. We have further demonstrated that this process can
be performed in a one-pot fashion in water from commercially
available starting materials, leading to materials that undergo
reversible photochromism to give stable, colorless 4-amino-
cyclopentenone zwitterions. We believe this work is a powerful
addition to the field of organic photochromes, providing a
versatile platform with unique properties that are synthetically
accessible to a wide range of researchers.
23
for a number of applications, including the spiropyran or
2
4
azobenzene systems, (∼20% and 30% molecular contraction
based on distance (Å) in published crystal structures,
respectively).
EXPERIMENTAL SECTION
General Methods. Unless stated otherwise, reactions were
conducted in flame-dried glassware under an atmosphere of air using
■
G
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reagent-grade solvents. All commercially obtained reagents were used
as received. Reaction temperatures were controlled using automated
temperature modulator, and unless stated otherwise, reactions were
performed at room temperature (rt, approximately 23 °C). Thin-layer
chromatography (TLC) was conducted with E. Merck silica gel 60
F254 precoated plates (0.25 mm) and visualized by exposure to UV
light (254 nm) or stained with anisaldehyde or potassium
permanganate. Flash column chromatography was performed using
1H), 6.06 (t, J = 12.3 Hz, 1H), 3.65 (s, 4H), 3.24 (t, J = 5.2 Hz, 4H),
1.61 (s, 6H); 13C NMR (150 MHz, CD Cl ) δ 164.4, 156.0, 150.2,
2
2
150.0, 140.1, 134.2, 129.3, 129.0, 121.0, 119.6, 116.8, 116.0, 103.3,
101.1, 93.9, 69.0, 49.4, 49.2, 46.3, 44.8, 28.0, 26.8, 26.5; IR (KBr) 3055,
2995, 2930, 2829, 1689, 1634, 1601, 1568, 1523, 1503, 1443, 1389,
1374, 1362, 1283, 1258, 1249, 1230, 1208, 1163, 1095, 1051, 1015
−
1
cm ; HRMS (ESI+) m/z 407.1581 (407.1583 calcd for
+
+
C H N O Na [M + Na] ).
21
24
2
5
1
normal-phase silica gel (60 Å, 230−240 mesh, Merck KGA). H NMR
5-((2Z,4E)-2-Hydroxy-5-((R)-2-methylpyrrolidin-1-yl)penta-
2,4-dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (20).
spectra were recorded at 500 or 600 MHz and are reported relative to
1
deuterated solvent signals. Data for H NMR spectra are reported as
Following general procedure A, the title compound was obtained as
1
follows: chemical shift (δ ppm), multiplicity, coupling constant (Hz),
a red solid (1.21g, 87%): H NMR (600 MHz, CD
2
Cl
2
) δ 11.28 (s,
13
and integration; C NMR spectra were recorded at 125 or 150 MHz.
Data for 13C NMR spectra are reported as follows: shift (δ ppm).
High-resolution mass spectra (HRMS) were obtained using a TOF
mass spectrometer, whereas infrared (IR) spectra were obtained using
25
1H), 7.42 (d, J = 12.0 Hz, 1H), 6.85 (s, 1H), 6.72 (d, J = 12.6 Hz, 1H),
5.90 (t, J = 12.3 Hz, 1H), 3.83 (d, J = 6.5 Hz, 1H), 3.56−3.47 (m, 2H),
1
3
2.17−1.87 (m, 4H), 1.59 (s, 6H), 1.28 (d, J = 6.5 Hz, 3H); C NMR
(150 MHz, CD Cl ) δ 167.0, 164.7, 153.9, 150.9, 144.6, 137.3, 103.9,
2 2
1
6
7
a Fourier transform infrared spectrometer. Compounds 6, 22, 33,
102.9, 89.6, 60.4, 49.2, 32.7, 26.4, 26.4, 22.8, 20.1; IR (KBr) 3065,
2996, 2877, 1676, 1599, 1509, 1466, 1441, 1369, 1345, 1311, 1259,
7
26
7
7
7
3
4, 35, 60, 73, and 78 were prepared by literature procedures.
−1
General Procedure A: Preparation of Stenhouse Adducts.
1232, 1191, 1135, 1004 cm ; HRMS (ESI+) m/z 330.1320 (330.1317
+
+
The activated furan (1.0 equiv) was added to tetrahydrofuran (0.4 M).
To this solution at 23 °C was added 1.0 equiv of secondary amine. The
reaction mixture was stirred at 23 °C for 10 min followed by cooling at
calcd for C16H21NO Na [M + Na] ).
5
(S)-Methyl-1-((1E,3Z)-5-(2,2-dimethyl-4,6-dioxo-1,3-dioxan-
5-ylidene)-4-hydroxypenta-1,3-dien-1-yl) pyrrolidine-2-car-
boxylate (21). Following general procedure A, the title compound
0
°C for 20 min. The reaction mixture was then filtered to collect the
1
was obtained as a green solid (1.33g, 84%): H NMR (600 MHz,
precipitated solid; the solid iswas washed with cold diethyl ether and
dried in vacuo to afford the title compounds.
CD Cl ) δ 11.14 (s, 1H), 7.29 (d, J = 12.5 Hz, 1H), 7.05 (s, 1H), 6.63
2
2
(
d, J = 12.3 Hz, 1H), 5.89 (t, J = 12.3 Hz, 1H), 4.37−4.32 (m, 1H),
3.70 (s, 3H), 2.24−2.17 (m, 2H), 2.07−1.98 (m, 2H), 1.74 (d, J = 3.6
Hz, 2H), 1.61 (d, J = 2.0 Hz, 6H); 13C NMR (150 MHz, CD
Cl ) δ
5
-((2Z,4E)-2-Hydroxy-5-(pyrrolidin-1-yl)penta-2,4-dien-1-yli-
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (8). Following general
procedure A, the title compound was obtained as a red solid (1.25g,
2
2
1
9
5%): H NMR (600 MHz, CD Cl ) δ 11.36 (s, 1H), 7.53 (d, J = 12.0
166.8, 164.2, 161.6, 153.6, 149.0, 141.8, 134.5, 110.0, 103.4, 103.1,
65.0, 62.9, 51.8, 48.8, 46.5, 29.7, 29.5, 26.5, 26.5, 23.9, 23.7, 23.5; IR
(KBr) 3068, 2990, 2953, 2880, 1742, 1688, 1627, 1485, 1450, 1407,
1391, 1362, 1340, 1274, 1244, 1234, 1200, 1141, 1118, 1043, 1006
2
2
Hz, 1H), 6.95 (s, 1H), 6.77 (d, J = 12.6 Hz, 1H), 5.97 (t, J = 12.3 Hz,
1
2
H), 3.71 (t, J = 6.5 Hz, 2H), 3.54 (t, J = 6.6 Hz, 2H), 2.14−2.08 (m,
13
H), 2.05−1.98 (m, 2H), 1.68 (s, 6H); C NMR (150 MHz, CD Cl )
2
2
−
1
δ 167.0, 164.6, 155.0, 150.7, 144.7, 137.7, 103.6, 103.0, 89.8, 54.1, 48.7,
cm ; HRMS (ESI+) m/z 374.1212 (374.1216 calcd for
+
+
2
1
6.4, 24.9, 24.9; IR (KBr) 2986, 2874, 1689, 1643, 1640, 1574, 1521,
453, 1391, 1371, 1344, 1308, 1263, 1228, 1200, 1152, 1104, 1004
C H21NO Na [M + Na] ). Crystal structure data for (S)-methyl
17 7
1-((1E,3Z)-5-(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)-4-hy-
droxypenta-1,3-dien-1-yl)pyrrolidine-2-carboxylate (21) can be
obtained free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif CCDC 844843.
−
1
cm ; HRMS (ESI+) m/z 316.1154 (316.1161 calcd for
C H NO Na [M + Na] ).
+
+
15
19
5
5
-((2Z,4E)-2-Hydroxy-5-(piperidin-1-yl)penta-2,4-dien-1-yli-
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (17). Following gen-
5-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-1-yli-
7
eral procedure A, the title compound was obtained as a red solid
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (22). Following gen-
1
(
1.10g, 80%): H NMR (600 MHz, CD Cl ) δ 11.38 (s, 1H), 7.32 (d,
eral procedure A, the title compound was obtained as a red solid
2
2
1
J = 12.2 Hz, 1H), 6.93 (s, 1H), 6.85−6.79 (m, 1H), 6.14 (t, J = 12.3
Hz, 1H), 3.58 (d, J = 23.3 Hz, 4H), 1.75 (s, 6H), 1.68 (s, 6H); 13
NMR (150 MHz, CD Cl ) δ 167.0, 164.7, 157.5, 151.6, 144.5, 137.0,
(1.13g, 85%): H NMR (600 MHz, CD
2
Cl
2
) δ 11.37−11.34 (m, 1H),
C
7.33 (d, J = 12.2 Hz, 1H), 6.96 (s, 1H), 6.80 (dd, J = 12.5, 1.3 Hz, 1H),
6.08 (t, J = 12.4 Hz, 1H), 3.54−3.45 (m, 4H), 1.68 (s, 6H), 1.31 (dt, J
2
2
= 18.1, 7.3 Hz, 6H); 13C NMR (150 MHz, CD
Cl ) δ 167.0, 164.6,
2 2
1
3
1
02.9, 101.7, 57.0, 47.9, 26.7, 26.4, 25.4, 23.5; IR (KBr) 3855, 3841,
678, 3446, 3075, 2987, 2941, 1720, 1681, 1639, 1599, 1571, 1524,
157.6, 151.4, 144.5, 137.8, 103.0, 102.2, 89.8, 52.0, 44.2, 26.4, 14.2,
12.1; IR (KBr) 3071, 2996, 2938, 1681, 1634, 1603, 1573, 1510, 1463,
1414, 1369, 1340, 1264, 1235, 1196, 1172, 1139, 1128, 1096, 1083,
−1
469, 1452, 1412, 1372, 1263, 1244, 1201, 1149, 1024 cm ; HRMS
+
(
ESI+) m/z 330.1318 (330.1317 calcd for C H NO Na [M +
16 21 5
+
−1
Na] ).
1059, 1015 cm ; HRMS (ESI+) m/z 318.1313 (318.1317 calcd for
+
+
5
-((2Z,4E)-2-Hydroxy-5-morpholinopenta-2,4-dien-1-yli-
C H21NO Na [M + Na] ). Crystal structure data for 5-((2Z,4E)-5-
15 5
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (18). Following gen-
(diethylamino)-2-hydroxypenta-2,4-dien-1-ylidene)-2,2-dimethyl-
7
eral procedure A, the title compound was obtained as a red solid
1,3-dioxane-4,6-dione (22) has been previously reported and can be
1
(
1.19g, 85%): H NMR (600 MHz, CD Cl ) δ 11.27 (s, 1H), 7.22 (d,
obtained free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif CCDC 865315.
5-((2Z,4E)-5-(Dipropylamino)-2-hydroxypenta-2,4-dien-1-
ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (23). Following
2
2
J = 12.4 Hz, 1H), 7.10 (s, 1H), 6.76 (d, J = 12.2 Hz, 1H), 6.09 (t, J =
1
3
1
2.3 Hz, 1H), 3.80−3.78 (m, 4H), 3.58 (s, 4H), 1.69 (s, 6H);
C
NMR (150 MHz, CD Cl ) δ 161.7, 156.1, 156.1, 149.8, 140.5, 140.5,
2
2
1
40.5, 134.3, 100.9, 69.3, 67.0, 49.6, 46.1, 44.7, 28.0, 26.8, 26.5; IR
general procedure A, the title compound was obtained as a red solid
1
(
KBr) 2988, 2934, 2857, 1688, 1633, 1604, 1569, 1520, 1442, 1392,
(252 mg, 78%): H NMR (500 MHz, CD
2
Cl
2
) δ 11.35 (s, 1H), 7.31
1
1
371, 1354, 1301, 1278, 1258, 1244, 1204, 1162, 1139, 1114, 1067,
(d, J = 12.2 Hz, 1H), 6.96 (s, 1H), 6.78 (d, J = 12.4 Hz, 1H), 6.06 (t, J
= 12.3 Hz, 1H), 3.38 (q, J = 7.4 Hz, 4H), 1.72 (dq, J = 9.6, 7.5 Hz,
4H), 1.67 (s, 6H), 0.96 (dt, J = 25.4, 7.4 Hz, 6H); C NMR (125
−
1
025, 1009 cm ; HRMS (ESI+) m/z 332.1105 (332.1110 calcd for
+
+
13
C H NO Na [M + Na] ). Crystal structure data for 5-((2Z,4E)-2-
15
19
6
hydroxy-5-morpholinopenta-2,4-dien-1-ylidene)-2,2-dimethyl-1,3-
dioxane-4,6-dione (18) can be obtained free of charge from the
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif CCDC 844844.
MHz, CD Cl ) δ 167.6, 165.3, 159.0, 152.0, 145.2, 138.5, 103.6, 102.9,
2
2
59.9, 51.8, 27.0, 22.8, 21.1, 11.6, 11.2; IR (KBr) 3150, 2993, 2917,
2696, 1644, 1589, 1548, 1501, 1447, 1403, 1359, 1315, 1278, 1232,
−1
1196, 1145, 1122 cm ; HRMS (ESI+) m/z 346.1620 (346.1630 calcd
+
+
5
-((2Z,4E)-2-Hydroxy-5-(4-phenylpiperazin-1-yl)penta-2,4-
for C H NO Na [M + Na] ).
17 25 5
dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (19). Fol-
5-((2Z,4E)-5-(Dibutylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (24). Following gen-
eral procedure A, the title compound was obtained as a red solid (288
lowing general procedure A, the title compound was obtained as a red
1
solid (273 mg, 71%): H NMR (600 MHz, CD Cl ) δ 11.22 (s, 1H),
2
2
1
7.24−7.14 (m, 4H), 7.00 (s, 1H), 6.89−6.83 (m, 4H), 6.73−6.66 (m,
mg, 82%): H NMR (500 MHz, CD Cl ) δ 11.34 (s, 1H), 7.31 (d, J =
2
2
H
dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
+
1
1
2
2.3 Hz, 1H), 6.95 (s, 1H), 6.78 (dd, J = 12.5, 1.5 Hz, 1H), 6.06 (t, J =
2.3 Hz, 1H), 3.41 (q, J = 7.0 Hz, 4H), 1.67 (s, 10H), 1.37 (dh, J =
9.9, 7.4 Hz, 4H), 0.97 (q, J = 7.5 Hz, 6H); 13C NMR (125 MHz,
HRMS (ESI+) m/z 378.1314 (378.1317 calcd for C H NO Na [M
+Na] ).
20
21
5
+
5-((2Z,4E)-2-Hydroxy-5-(isoindolin-2-yl)penta-2,4-dien-1-yli-
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (30). Following gen-
eral procedure A, the title compound was obtained as a red solid (870
mg, 91%): H NMR (600 MHz, CD Cl ) δ 11.21 (s, 1H), 7.48 (d, J =
CD Cl ) δ 167.6, 165.2, 159.0, 152.0, 145.2, 138.2, 103.6, 103.0, 58.1,
2
2
5
1
1
0.1, 31.4, 29.7, 27.0, 20.7, 20.2, 14.0, 140; IR (KBr) 3157, 2991, 2923,
691, 1645, 1592, 1544, 1498, 1446, 1404, 1357, 1311, 1274, 1228,
191, 1136, 1116 cm ; HRMS (ESI+) m/z 374.1947 (374.1943 calcd
1
2
2
−1
12.2 Hz, 1H), 7.27 (d, J = 26.5 Hz, 4H), 7.05 (s, 1H), 6.69 (d, J = 12.2
Hz, 1H), 5.96 (t, J = 12.3 Hz, 1H), 4.97 (s, 2H), 4.78 (s, 2H), 1.61 (s,
+
+
for C H NO Na [M + Na] ).
19
29
5
6
H); 13C NMR (150 MHz, CD Cl ) δ 153.6, 149.0, 141.1, 128.4,
5
-((2Z,4E)-5-(Dihexylamino)-2-hydroxypenta-2,4-dien-1-yli-
2 2
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (25). Following gen-
eral procedure A, the title compound was obtained as a red solid (371
mg, 91%): H NMR (500 MHz, CD Cl ) δ 11.34 (s, 1H), 7.31 (d, J =
128.2, 122.8, 122.5, 103.3, 103.0, 58.3, 54.5, 26.5; IR (KBr) 3063,
985, 2958, 1688, 1637, 1611, 1565, 1505, 1468, 1451, 1368, 1349,
2
1
−1
1
284, 1268, 1235, 1223, 1198, 1180, 1151, 1114, 1025, 1006 cm ;
2
2
+
HRMS (ESI+) m/z 364.1163 (364.1161 calcd for C H NO Na [M
12.2 Hz, 1H), 6.94 (s, 1H), 6.78 (dd, J = 12.5, 1.5 Hz, 1H), 6.06 (t, J =
12.3 Hz, 1H), 3.41 (q, J = 6.7 Hz, 5H), 1.67 (s, 10H), 1.38−1.25 (m,
16H), 0.90 (ddt, J = 10.8, 7.6, 4.4 Hz, 6H); C NMR (125 MHz,
19 19
5
+
+
Na] ). Crystal structure data for 5-((2Z,4E)-2-hydroxy-5-(isoindo-
13
lin-2-yl)penta-2,4-dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-
dione (30) can be obtained free of charge from the Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif CCDC 846378.
5-((2Z,4E)-5-(Dibenzylamino)-2-hydroxypenta-2,4-dien-1-
ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (31). Following
general procedure A, the title compound was obtained as a green
solid (1.42g, 75%): H NMR (600 MHz, CD Cl ) δ 11.25 (s, 1H),
.59 (d, J = 12.4 Hz, 1H), 7.40 (tt, J = 14.8, 6.6 Hz, 6H), 7.22 (dd, J =
12.8, 7.3 Hz, 4H), 7.13 (s, 1H), 6.83 (d, J = 12.2 Hz, 1H), 6.23 (t, J =
2.3 Hz, 1H), 4.56 (d, J = 5.5 Hz, 4H), 1.68 (s, 6H); C NMR (150
MHz, CD Cl ) δ 166.9, 164.4, 157.7, 150.2, 145.2, 140.8, 134.1, 133.8,
129.2, 129.1, 128.8, 128.8, 128.4, 128.3, 128.1, 127.5, 127.3, 103.4,
02.0, 92.2, 60.0, 54.5, 51.7, 26.6, 26.5; IR (KBr) 3469, 3058, 3027,
992, 2932, 1696, 1626, 1553, 1489, 1476, 1449, 1391, 1365, 1346,
291, 1261, 1231, 1197, 1139, 1111, 1030, 1016, 1003 cm ; HRMS
(ESI+) m/z 442.1637 (442.1630 calcd for C25H25NO Na [M +
Na] ). Crystal structure data for 5-((2Z,4E)-5-(dibenzylamino)-2-
hydroxypenta-2,4-dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-
dione (31) can be obtained free of charge from the Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif CCDC 844842.
-((2Z,4E)-2-Hydroxy-5-(methyl(phenyl)amino)penta-2,4-
dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (32). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (74 mg, 22%): H NMR (600 MHz, CD Cl ) δ 7.67 (d, J
5.5 Hz, 1H), 7.24 (t, J = 7.8 Hz, 2H), 6.84 (d, J = 8.1 Hz, 2H), 6.78
t, J = 7.3 Hz, 1H), 6.43 (d, J = 4.6 Hz, 1H), 5.52 (s, 1H), 4.00 (s,
H), 3.50−3.43 (d, J = 3.4 Hz, 1H), 2.79 (s, 3H), 1.70 (s, 6H);
NMR (125 MHz, CD Cl ) δ 163.8, 149.9, 134.7, 130.4, 130.0, 118.9,
114.1, 106.2, 63.6, 48.4, 45.0, 32.8, 28.4, 27.2, 27.2. IR (ATR) 3060,
999, 2921, 1780, 1742, 1710, 1596, 1503, 1470, 1382, 1324, 1269,
197, 1147, 1104, 1015, 990, 927, 871, 791, 749, 694 cm ; HRMS
ESI+) m/z 352.1147 (352.1161 calcd for C H NO Na [M +
CD Cl ) δ 167.6, 165.3, 159.0, 152.0, 145.2, 138.2, 103.6, 103.0, 58.3,
2
2
50.3, 31.9, 31.9, 31.9, 29.4, 27.6, 27.1, 27.0, 26.6, 23.1, 23.1, 23.0, 14.3;
IR (KBr) 3163, 2996, 2921, 1694, 1639, 1585, 1537, 1487, 1435, 1395,
−1
1344, 1297, 1260, 1223, 1183, 1125, 1109 cm ; HRMS (ESI+) m/z
+
+
430.2573 (430.2569 calcd for C H NO Na [M + Na] ).
23
37
5
5
-((2Z,4E)-5-(Dioctylamino)-2-hydroxypenta-2,4-dien-1-yli-
1
2
2
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (26). Following gen-
eral procedure A, the title compound was obtained as a red solid
7
1
(
1.75g, 83%): H NMR (600 MHz, CD Cl ) δ 11.36 (s, 1H), 7.30 (d,
2
2
13
1
J = 12.2 Hz, 1H), 6.96 (s, 1H), 6.78 (d, J = 12.4 Hz, 1H), 6.07 (t, J =
2
2
1
2
1
3
2.3 Hz, 1H), 3.41 (q, J = 7.2 Hz, 4H), 1.68 (s, 6H), 1.41−1.18 (m,
4H), 0.90 (t, J = 6.8 Hz, 6H); 13C NMR (150 MHz, CD Cl ) δ
2
2
1
2
1
67.0, 164.6, 158.3, 151.3, 144.6, 137.7, 103.0, 102.3, 89.8, 57.7, 49.7,
1.7, 31.7, 29.1, 29.1, 29.0, 28.8, 27.3, 27.0, 26.9, 26.4, 26.4, 22.6, 13.8;
−1
IR (KBr) 2924, 2855, 1719, 1676, 1575, 1503, 1462, 1416, 1391, 1346,
1
m/z 486.3181 (486.3195 calcd for C H NO Na [M + Na] ).
+
−1
5
287, 1262, 1231, 1199, 1142, 1117, 1047, 1029 cm ; HRMS (ESI+)
+
+
+
27
45
5
5
-((2Z,4E)-5-(Diallylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-2,2-dimethyl-1,3-dioxane-4,6-dione (27). Following gen-
eral procedure A, the title compound was obtained as a purple solid
1
(
968 mg, 68%): H NMR (600 MHz, CD Cl ) δ 11.17 (s, 1H), 7.23
2
2
5
(
=
3
d, J = 12.4 Hz, 1H), 7.00 (s, 1H), 6.65 (d, J = 12.3 Hz, 1H), 5.96 (t, J
12.3 Hz, 1H), 5.75 (dt, J = 13.8, 7.6 Hz, 2H), 5.32−5.15 (m, 4H),
.94 (dd, J = 16.9, 5.0 Hz, 4H), 1.60 (s, 6H); 13C NMR (150 MHz,
CD Cl ) δ 166.9, 164.4, 157.1, 150.1, 145.1, 140.5, 131.2, 129.4, 120.5,
1
2
2
2
2
=
1
2
1
19.1, 119.0, 103.3, 102.0, 91.9, 59.1, 51.3, 26.5; IR (KBr) 3071, 3003,
943, 1698, 1646, 1612, 1561, 1499, 1446, 1368, 1299, 1283, 1242,
207, 1164 cm ; HRMS (ESI+) m/z 342.1324 (342.1317 calcd for
(
1
13
C
−
1
2
2
+
+
C H NO Na [M +Na] ).
17
21
5
5
-((2Z,4E)-5-(Benzyl(methyl)amino)-2-hydroxypenta-2,4-
2
1
(
dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (28). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (1.31g, 85%): H NMR (600 MHz, CD Cl ) δ 11.32 (d, J
=
−1
+
1
18 19
5
+
2
2
Na] ).
1.6 Hz, 1H), 7.53 (d, J = 12.2 Hz, 1H), 7.42 (qd, J = 7.8, 7.2, 3.7 Hz,
5
-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (34).
Following general procedure A, the title compound was obtained as
a purple solid (260 mg, 85%): H NMR (500 MHz, CD Cl ) δ 12.50
(s, 1H), 7.30 (d, J = 12.2 Hz, 1H), 7.06 (s, 1H), 6.82 (dd, J = 12.3, 1.5
Hz, 1H), 6.10 (t, J = 12.3 Hz, 1H), 3.50 (dq, J = 25.4, 7.2 Hz, 4H),
3.29 (s, 3H), 3.27 (s, 3H), 1.31 (dt, J = 13.0, 7.2 Hz, 6H); C NMR
(151 MHz, CD Cl ) δ 165.7, 163.6, 157.8, 151.8, 146.7, 138.2, 103.3,
98.1, 52.6, 44.8, 28.6, 28.5, 14.8, 12.7; IR (KBr) 3365, 2944, 2486,
1685, 1618, 1592, 1566, 1509, 1460, 1418, 1373, 1328, 1309, 1286,
1270 cm ; HRMS (ESI+) m/z 330.1433 (330.1430 calcd for
C H N O Na [M +Na] ). Crystal structure data for 5-((2Z,4E)-
-(diethylamino)-2-hydroxypenta-2,4-dien-1-ylidene)-1,3-dimethyl-
pyrimidine-2,4,6(1H,3H,5H)-trione (34) can be obtained free of
charge from the Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif CCDC 1026490.
7
3H), 7.31−7.18 (m, 2H), 7.08 (s, 1H), 6.82 (dd, J = 12.5, 1.6 Hz, 1H),
6.14 (dt, J = 93.0, 12.3 Hz, 1H), 4.61 (d, J = 18.0 Hz, 2H), 3.13 (d, J =
1
22.7 Hz, 3H), 1.68 (d, J = 5.1 Hz, 6H); 13C NMR (150 MHz,
1
2
2
CD Cl ) δ 166.9, 164.5, 158.8, 158.0, 150.7, 150.4, 145.1, 139.9, 139.5,
2
2
1
1
3
1
34.0, 129.2, 129.1, 128.8, 128.7, 128.5, 128.4, 127.8, 127.4, 103.2,
02.1, 102.0, 62.9, 53.8, 53.6, 53.4, 53.3, 53.1, 36.3, 26.5; IR (KBr)
082, 3028, 2990, 2940, 1695, 1610, 1565, 1502, 1447, 1401, 1386,
1
3
2
2
−1
356, 1276, 1260, 1239, 1200, 1150, 1065, 1032, 1003 cm ; HRMS
+
+
(
ESI+) m/z 366.1320 (366.1317 calcd for C H NO Na [M +Na] ).
19 21 5
−1
5
-((2Z,4E)-5-(3,4-Dihydroisoquinolin-2(1H)-yl)-2-hydroxy-
penta-2,4-dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione
29). Following general procedure A, the title compound was obtained
+
+
15
21
3
4
(
5
1
as a red solid (1.32 g, 82%): H NMR (600 MHz, CD Cl ) δ 11.24 (s,
2
2
1
H), 7.36 (d, J = 12.4 Hz, 1H), 7.25−6.90 (m, 7H), 6.71 (d, J = 12.3
Hz, 1H), 6.06 (d, J = 12.5 Hz, 1H), 4.64 (s, 2), 3.75−3.64 (m, 2H),
13
2.96 (d, J = 18.9 Hz, 2H), 1.60 (s, 6H); C NMR (150 MHz,
2
-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1H-indene-1,3(2H)-dione (36). Following general procedure
CD Cl ) δ 166.9, 164.4, 156.7, 156.6, 150.1, 150.0, 140.1, 128.7, 128.6,
2
2
1
2
1
27.3, 127.1, 127.1, 127.0, 126.5, 126.4, 125.6, 101.5, 101.4, 52.4, 48.3,
9.3, 26.5; IR (KBr) 3469, 3062, 2992, 2937, 1690, 1632, 1609, 1561,
500, 1458, 1440, 1364, 1283, 1267, 1234, 1203, 1153, 1051 cm ;
A, the title compound was obtained as a dark blue solid (259 mg,
1
87%): H NMR (600 MHz, CD Cl ) δ 11.51 (s, 1H), 7.60 (dt, J =
2
2
−1
19.4, 2.6 Hz, 2H), 7.57−7.52 (m, 2H), 7.24 (d, J = 12.2 Hz, 1H), 6.71
I
dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
−
1
(
d, J = 12.3 Hz, 1H), 6.64 (s, 1H), 6.04 (t, J = 12.3 Hz, 1H), 3.46 (dq,
836, 757 cm ; HRMS (ESI+) m/z 358.1740 (358.1743 calcd for
17 25 3 4
13
+
+
J = 28.1, 7.2 Hz, 4H), 1.27 (dt, J = 7.9, 4.5 Hz, 6H); C NMR (125
MHz, CD Cl ) δ 193.2, 190.8, 156.4, 147.8, 147.3, 141.2, 140.9, 133.5,
1
C H N O Na [M + Na] ).
5-((2Z,4E)-5-(Dibutylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (49). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (276 mg, 76%): H NMR (500 MHz, CD Cl ) δ: 12.49
s, 1H), 7.29 (d, J = 12.2 Hz, 1H), 7.04 (s, 1H), 6.81 (d, J = 12.4 Hz,
H), 6.08 (t, J = 12.3 Hz, 1H), 3.42 (dt, J = 12.2, 7.7 Hz, 4H), 3.29 (s,
3H), 3.26 (s, 3H), 1.71−1.62 (m, 4H), 1.37 (dh, J = 30.1, 7.4 Hz, 4H),
0.97 (dt, J = 11.4, 7.4 Hz, 6H); 13C NMR (125 MHz, CD
Cl ) δ
165.1, 163.0, 158.0, 151.2, 146.2, 137.4, 102.9, 57.4, 49.5, 30.9, 29.1,
28.0, 27.9, 20.2, 19.6, 13.4, 13.3; IR (KBr) 2971, 2919, 2813, 1695,
613, 1586, 1558, 1484, 1451, 1423, 1370, 1339, 1257, 1221, 1176,
122, 1063, 1007, 977, 936, 836, 759 cm ; HRMS (ESI+) m/z
86.2049 (386.2056 calcd for C H N O Na [M + Na] ).
2
2
33.2, 132.0, 121.3, 121.1, 114.5, 102.6, 52.3, 44.5, 14.8, 12.6. IR
(
ATR): 3007, 2971, 2924, 2869, 1674, 1613, 1583, 1483, 1439, 1373,
1
−1
1
+
353, 1331, 1262, 1163, 1146, 1110, 974, 905, 765 cm ; HRMS (ESI
2
2
+
+
(
1
) m/z 320.1262 (320.1263 calcd for C H NO Na [M + Na] ).
18
19
3
5-((2Z,4E)-2-Hydroxy-5-(pyrrolidin-1-yl)penta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (42). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (275 mg, 90%): H NMR (600 MHz, CDCl ) δ 12.53 (s,
1
5
3
2
1
2
2
1
3
H), 7.43 (d, J = 12.2 Hz, 1H), 7.14 (s, 1H), 6.72 (d, J = 12.4 Hz, 1H),
.98 (t, J = 12.3 Hz, 1H), 3.70 (t, J = 6.8 Hz, 3H), 3.52 (t, J = 7.0 Hz,
H), 3.35 (d, J = 6.2 Hz, 7H), 3.21 (s, 2H), 2.13 (p, J = 6.8 Hz, 4H),
1
1
3
−
1
+
+
.04 (p, J = 6.6 Hz, 4H); 13C NMR (150 MHz, CDCl ) δ 163.3, 153.6,
19 29
3
4
3
5
-((2Z,4E)-5-(Dihexylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (50). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (394 mg, 94%): H NMR (500 MHz, CD Cl ) δ 12.49 (s,
50.0, 146.7, 139.4, 104.0, 70.0, 53.8, 48.4, 28.4, 28.3, 25.0, 22.7; IR
(
1
KBr) 2961, 2915, 2763, 1693, 1617, 1580, 1559, 1491, 1454, 1419,
370, 1343, 1266, 1226, 1177, 1105, 1043, 967, 941, 924, 829, 754
1
−
1
2
2
cm ; HRMS (ESI+) m/z 328.1263 (328.1273 calcd for
C H N O Na [M + Na] ).
+
+
1H), 7.30 (d, J = 12.2 Hz, 1H), 7.03 (s, 1H), 6.82 (d, J = 12.1 Hz, 1H),
15
19
3
4
6
3
6
.08 (t, J = 12.3 Hz, 1H), 3.41 (dt, J = 10.8, 7.8 Hz, 4H), 3.29 (s, 3H),
.26 (s, 3H), 1.69−1.65 (m, 4H), 1.34−1.30 (m, 12H), 0.91−0.89 (m,
H); 13C NMR (125 MHz, CD Cl ) δ 165.0, 163.0, 158.0, 151.3,
146.2, 137.3, 103.0, 57.7, 49.7, 31.3, 31.3, 28.8, 28.0, 27.9, 27.0, 26.5,
6.4, 26.0, 22.5, 22.4, 13.7; IR (KBr) 2971, 2919, 2818, 1699, 1613,
568, 1553, 1484, 1457, 1423, 1369, 1343, 1264, 1220, 1173, 1123,
075, 1009, 979, 944, 848, 766 cm ; HRMS (ESI+) m/z 442.2681
(442.2682 calcd for C H N O Na [M + Na] ).
-((2Z,4E)-5-(Dioctylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (51). Fol-
5
-((2Z,4E)-2-Hydroxy-5-(piperidin-1-yl)penta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (43). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (297 mg, 93%): H NMR (500 MHz, CD Cl ) δ 12.52 (s,
1
6
3
2
1
2
1
2
2
1
2
2
2
1
1
H), 7.32 (d, J = 12.1 Hz, 1H), 7.01 (s, 1H), 6.85 (d, J = 12.5 Hz, 1H),
.16 (t, J = 12.3 Hz, 1H), 3.71−3.65 (m, 2H), 3.61−3.58 (m, 2H),
−
1
.55 (bs, 2H), 3.29 (s, 3H), 3.26 (s, 3H), 3.17 (bs, 2H), 1.84−1.79 (m,
H); 13C NMR (125 MHz, CD Cl ) δ 165.0, 163.0, 157.3, 151.6,
+
+
23
37
3
4
2
2
5
46.1, 136.7, 102.4, 67.7, 57.0, 27.9, 25.5, 23.6; IR (KBr) 2964, 2915,
832, 1694, 1616, 1578, 1557, 1488, 1452, 1419, 1369, 1345, 1260,
−1
lowing general procedure A, the title compound was obtained as a
purple solid (414 mg, 87%): H NMR (500 MHz, CD Cl ) δ 12.49 (s,
217, 1164, 1105, 1043, 967, 941, 924, 829, 754 cm ; HRMS (ESI+)
1
+
+
2
2
m/z 342.1426 (342.1430 calcd for C H N O Na [M + Na] ).
16
21
3
4
1
6
3
H), 7.29 (d, J = 12.2 Hz, 1H), 7.03 (s, 1H), 6.82 (d, J = 12.5 Hz, 1H),
.08 (t, J = 12.3 Hz, 1H), 3.41 (dt, J = 11.0, 7.7 Hz, 4H), 3.29 (s, 3H),
.26 (s, 3H), 1.70−1.65 (m, 4H), 1.32−1.27 (m, 20H), 0.90−0.87 (m,
5
-((2Z,4E)-2-Hydroxy-5-((R)-2-methylpyrrolidin-1-yl)penta-
2
,4-dien-1-ylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-
trione (46). Following general procedure A, the title compound was
13
1
6H); C NMR (125 MHz, CD Cl ) δ 165.0, 163.0, 158.0, 151.3,
2 2
obtained as a purple solid (278 mg, 87%): H NMR (600 MHz,
CDCl ) δ 12.53 (s, 1H), 7.38 (d, J = 12.2 Hz, 1H), 7.15 (s, 1H), 6.75
1
2
2
46.2, 137.3, 102.9, 57.7, 49.7, 31.7, 31.7, 31.7, 29.1, 29.1, 29.1, 29.1,
8.9, 28.0, 27.9, 27.1, 26.9, 26.4, 22.6, 13.8; IR (KBr) 2969, 2917,
806, 1693, 1616, 1576, 1557, 1487, 1453, 1425, 1360, 1342, 1267,
1226, 1180, 1124, 1073, 1006, 978, 941, 851, 761 cm ; HRMS (ESI
) m/z 498.3296 (498.3308 calcd for C H N O Na [M + Na] ).
-((2Z,4E)-5-(Diallylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (52). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (315 mg, 95%): H NMR (500 MHz, CD Cl ) δ 12.40 (s,
3
(
d, J = 12.6 Hz, 1H), 5.99 (t, J = 12.3 Hz, 1H), 3.89 (q, J = 6.5 Hz,
1
5
H), 3.58 (q, J = 6.7 Hz, 2H), 3.35 (d, J = 5.8 Hz, 7H), 2.32−1.95 (m,
−1
H), 1.71 (dq, J = 12.9, 6.6 Hz, 1H), 1.37 (d, J = 6.5 Hz, 3H); 13
C
+
+
+
27 45 3 4
NMR (150 MHz, CDCl ) δ 165.1, 152.3, 152.0, 150.2, 146.7, 139.2,
3
5
1
2
1
04.2, 59.9, 49.0, 32.9, 28.4, 28.3, 22.9, 20.5; IR (KBr) 2965, 2913,
821, 1694, 1616, 1576, 1557, 1487, 1452, 1421, 1369, 1346, 1260,
−1
219, 1166, 1109, 1050, 976, 968, 924, 829, 754 cm ; HRMS (ESI+)
1
+
+
2
2
m/z 342.1430 (342.1430 calcd for C H N O Na [M + Na] ).
16
21
3
4
1
H), 7.31 (d, J = 12.4 Hz, 1H), 7.15 (s, 1H), 6.78−6.75 (m, 2H), 6.06
t, J = 12.3 Hz, 1H), 5.40−5.33 (m, 2H), 5.31−5.24 (m, 2H), 4.07−
(
S)-Methyl-1-((1E,3Z)-5-(1,3-dimethyl-2,4,6-trioxotetrahy-
(
3
dropyrimidin-5(2H)-ylidene)-4-hydroxypenta-1,3-dien-1-yl)-
pyrrolidine-2-carboxylate (47). Following general procedure A, the
title compound was obtained as a purple solid (189 mg, 52%: H
NMR (500 MHz, CD Cl ) δ 12.35 (s, 1H), 7.37 (d, J = 12.1 Hz, 1H),
7
1
3
.96 (m, 4H), 3.36 (m, 2H), 3.29 (s, 3H), 3.27 (s, 3H); C NMR
Cl ) δ 165.8, 163.5, 157.4, 152.2, 150.6, 147.2, 140.7,
31.9, 130.1, 121.1, 119.6, 103.2, 59.7, 50.8, 30.3, 28.7, 28.6; IR (KBr)
967, 2911, 2809, 1694, 1610, 1552, 1459, 1428, 1361, 1348, 1263,
1
(125 MHz, CD
2
2
1
2
1
2
2
.18 (s, 1H), 6.72 (d, J = 12.5 Hz, 1H), 5.96 (t, J = 12.3 Hz, 1H), 4.43
−
1
222, 1174, 1116, 1060, 991, 965, 931, 836, 758 cm ; HRMS (ESI+)
m/z 354.1426 (354.1430 calcd for C H N O Na [M + Na] ).
5-((2Z,4E)-5-(Benzyl(methyl)amino)-2-hydroxypenta-2,4-
dien-1-ylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-tri-
one (53). Following general procedure A, the title compound was
obtained as a purple solid (327 mg, 92%): H NMR (500 MHz,
CD Cl ) δ 12.44 (s, 1H), 7.46 (d, J = 12.3 Hz, 1H), 7.40 (dd, J = 13.8,
.2 Hz, 3H), 7.24 (d, J = 7.4 Hz, 2H), 7.18 (s, 1H), 6.82 (d, J = 12.3
Hz, 1H), 6.06 (t, J = 12.3 Hz, 1H), 4.58 (s, 2H), 3.30 (s, 3H), 3.27 (s,
H), 3.03 (s, 3H); C NMR (150 MHz, CD Cl ) δ 165.8, 163.5,
57.8, 152.3, 150.4, 147.3, 140.7, 134.7, 129.7, 129.4, 128.3, 128.0,
02.9, 63.4, 36.9, 28.7, 28.6; IR (KBr) 2961, 2918, 2816, 1692, 1614,
1573, 1559, 1486, 1456, 1421, 1369, 1341, 1261, 1221, 1179, 1118,
062, 994, 968, 932, 841, 752 cm ; HRMS (ESI+) m/z 378.1428
(
dd, J = 7.7, 4.3 Hz, 1H), 3.76 (s, 3H), 3.71−3.58 (m, 2H), 3.28 (s,
+
+
17
21
3
4
3
2
1
2
1
8
H), 3.25 (s, 3H), 2.32−2.18 (m, 2H), 2.07 (tdd, J = 12.8, 8.0, 5.9 Hz,
H); 13C NMR (125 MHz, CD Cl ) δ 171.3, 165.8, 163.3, 153.9,
2
2
52.2, 149.4, 147.5, 141.9, 135.0, 104.3, 65.6, 53.5, 49.4, 30.1, 28.7,
8.6, 24.1; IR (KBr) 2966, 2912, 2813, 1694, 1615, 1573, 1557, 1486,
452, 1425, 1369, 1347, 1260, 1222, 1180, 1126, 1071, 1004, 968, 924,
1
2
2
−1
29, 754 cm ; HRMS (ESI+) m/z 386.1321 (386.1328 calcd for
7
+
+
C H N O Na [M + Na] ).
17
21
3
6
5
-((2Z,4E)-5-(Dipropylamino)-2-hydroxypenta-2,4-dien-1-
13
3
1
1
2 2
ylidene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (48).
Following general procedure A, the title compound was obtained as
a purple solid (278 mg, 83%): H NMR (500 MHz, CD Cl ) δ 12.50
(
1
3
2
1
1
1
1
2
2
s, 1H), 7.31 (d, J = 12.2 Hz, 1H), 7.05 (s, 1H), 6.83 (d, J = 12.5 Hz,
−1
1
(
H), 6.09 (t, J = 12.3 Hz, 1H), 3.39 (dt, J = 11.8, 7.8 Hz, 4H), 3.29 (s,
H), 3.26 (s, 3H), 1.72 (dh, J = 16.8, 9.6, 8.1 Hz, 4H), 0.97 (dt, J =
8.8, 7.4 Hz, 6H); 13C NMR (125 MHz, CD Cl ) δ 165.6, 163.6,
+
+
378.1430 calcd for C H N O Na [M + Na] ).
19 21 3 4
5
-((2Z,4E)-5-(3,4-Dihydroisoquinolin-2(1H)-yl)-2-hydroxy-
2
2
penta-2,4-dien-1-ylidene)-1,3-dimethylpyrimidine-2,4,6-
58.8, 151.9, 146.8, 138.1, 103.4, 59.8, 51.8, 28.6, 28.5, 22.8, 21.1, 11.7,
1.5, 11.2; IR (KBr) 2972, 2920, 2813, 1695, 1614, 1569, 1558, 1485,
451, 1424, 1386, 1346, 1260, 1221, 1176, 1122, 1078, 1009, 977, 936,
(1H,3H,5H)-trione (54). Following general procedure A, the title
1
compound was obtained as a purple solid (301 mg, 82%): H NMR
(500 MHz, CD Cl ) δ 12.48 (s, 1H), 7.45 (d, J = 12.9 Hz, 1H), 7.30−
2
2
J
dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
7
4
2
1
4
1
1
.10 (m, 6H), 6.84 (d, J = 12.3 Hz, 1H), 6.17 (d, J = 11.9 Hz, 1H),
.73 (s, 2H), 3.81 (s, 2H), 3.30 (s, 3H), 3.26 (s, 3H), 3.09−2.99 (m,
H); 13C NMR (125 MHz, CD Cl ) δ 165.7, 163.6, 157.0, 152.3,
CD Cl ) δ 165.3, 163.3, 159.3, 159.1, 158.2, 152.7, 151.6, 146.3, 136.4,
2
2
129.9, 129.2, 128.8, 114.1, 103.6, 96.9, 55.4, 52.2, 44.4, 14.1, 12.2.
IR(ATR) 3444, 2984, 2928, 2837, 1697, 1587, 1508, 1462, 1432, 1368,
1349, 1244, 1181, 1143, 1117, 1073, 1026, 987, 961, 828, 769, 748
2
2
50.6, 140.3, 129.5, 129.3, 128.5, 127.7, 127.1, 102.7, 68.3, 52.6, 45.4,
2.4, 29.9, 28.7, 28.6, 26.1, 25.9; IR (KBr) 2965, 2913, 2814, 1697,
619, 1573, 1556, 1481, 1456, 1426, 1362, 1345, 1269, 1228, 1175,
−
1
cm ; HRMS (ESI+) m/z 514.1949 (514.1954 calcd for
+
+
C H N O Na [M + Na] ).
27
29
3
6
−1
120, 1065, 998, 972, 933, 838, 759 cm ; HRMS (ESI) m/z 390.1425
1,3-Bis(4-chlorophenyl)-5-((2Z,4E)-5-(diethylamino)-2-hy-
+
+
(
390.1430 calcd for C H N O Na [M + Na] ).
droxypenta-2,4-dien-1-ylidene)pyrimidine-2,4,6(1H,3H,5H)-tri-
20
21
3
4
one (69). Following general procedure A, the title compound was
1
,3-Dibutyl-5-((2Z,4E)-5-(diethylamino)-2-hydroxypenta-
1
2
,4-dien-1-ylidene)pyrimidine-2,4,6(1H,3H,5H)-trione (59). Fol-
obtained as a purple solid (445 mg, 89%): H NMR (600 MHz,
lowing general procedure A, the title compound was obtained as a
purple solid (341 mg, 87%): H NMR (600 MHz, CD Cl ) δ 12.56 (s,
CD Cl ) δ 12.08 (s, 1H), 7.44 (dd, J = 11.2, 8.5 Hz, 4H), 7.40 (d, J =
2 2
1
12.1 Hz, 1H), 7.24 (dd, J = 18.5, 8.6 Hz, 4H), 6.97 (s, 1H), 6.93 (dd, J
= 12.8, 1.4 Hz, 1H), 6.20 (t, J = 12.4 Hz, 1H), 3.54 (dq, J = 25.9, 7.3
Hz, 4H), 1.32 (dt, J = 18.1, 7.2 Hz, 6H); 13C NMR (125 MHz,
2
2
1
6
2
H), 7.28 (d, J = 12.3 Hz, 1H), 7.06 (s, 1H), 6.80 (d, J = 11.5 Hz, 1H),
.07 (t, J = 12.3 Hz, 1H), 3.87 (dt, J = 14.9, 7.5 Hz, 4H), 3.49 (dq, J =
4.8, 7.2 Hz, 4H), 1.55 (m, 4H), 1.40−1.23 (m, 10H), 0.93 (q, J = 7.3
CD Cl ) δ 163.4, 159.6, 154.4, 151.5, 146.9, 135.5, 134.3, 131.1, 131.0,
2 2
13
Hz, 6H); C NMR (126 MHz, CD Cl ) δ 165.5, 163.3, 157.4, 151.9,
129.6, 129.6, 104.9, 96.6, 54.4, 53.0, 45.3, 14.7, 12.8. IR(ATR) 3468,
3007, 2986, 2928, 1701, 1625, 1589, 1489, 1461, 1430, 1366, 1347,
1275, 1258, 1224, 1181, 1142, 1116, 1073, 1014, 959, 824, 810, 765,
2
2
1
2
1
7
51.3, 146.8, 138.7, 103.0, 98.7, 52.5, 44.7, 41.8, 41.7, 30.9, 30.9, 20.8,
0.8, 14.8, 14.2, 14.2, 12.7. IR (ATR): 2958, 2932, 2873, 1691, 1622,
596, 1556, 1497, 1405, 1373, 1339, 1261, 1205, 1143, 1076, 990, 907,
−
1
750 cm ; HRMS (ESI+) m/z 522.0953 (522.0963 calcd for
+
+
−
1
C H N O Cl Na [M + Na] ).
79 cm ; HRMS (ESI+) m/z 414.2379 (414.2369 calcd for
25 23
3
4
2
+
+
General Procedure B: Photoisomerization of Stenhouse
Adducts to Cyclopentenones. Stenhouse adduct was suspended in
methanol (0.04 M). The reaction mixture was irradiated with a GE
Crystal Clear 200 bulb (200 W, 3780 lm) placed approximately 10 in.
from the reaction vessel at ambient temperature with stirring for 12 h.
The reaction mixture was cooled to 0 °C for 20 min and then filtered
to collect the precipitated solid; the solid was washed with cold diethyl
ether and dried in vacuo to afford the title compounds.
C H N O Na [M + Na] )
21
33
3
4
5
-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-1-yli-
dene)-1,3-dioctylpyrimidine-2,4,6(1H,3H,5H)-trione (61). Fol-
lowing general procedure A, the title compound was obtained as a
purple solid (453 mg, 90%): H NMR (600 MHz, CD Cl ) δ 12.56 (s,
1
2
2
1
6
H), 7.28 (d, J = 12.2 Hz, 1H), 7.06 (s, 1H), 6.79 (d, J = 12.4 Hz, 1H),
.07 (t, J = 12.3 Hz, 1H), 3.92−3.81 (m, 4H), 3.49 (dq, J = 24.7, 7.2
Hz, 4H), 1.57 (dt, J = 18.5, 7.4 Hz, 4H), 1.28 (m, 26H), 0.87 (td, J =
.0, 2.1 Hz, 6H); 13C NMR (125 MHz, CD Cl ) δ 165.5, 163.3, 157.4,
2
,2-Dimethyl-4-oxo-5-(2-oxo-5-(pyrrolidin-1-ium-1-yl)-
7
1
2
1
2 2
cyclopent-3-en-1-yl)-4H-1,3-dioxin-6-olate (9). Following general
51.8, 151.3, 146.8, 138.7, 103.0, 98.8, 52.5, 42.1, 32.4, 30.0, 29.9, 28.8,
7.6, 23.2, 14.4. IR (ATR) 2956, 2923, 2854, 1691, 1620, 1595, 1556,
492, 1454, 1403, 1370, 1337, 1260, 1198, 1074, 989, 907, 779 cm ;
procedure B, the title compound was obtained as a white solid (87.8
1
−1
mg, 82%): H NMR (600 MHz, D O) δ 7.87 (d, J = 6.1 Hz, 1H), 6.67
2
+
(d, J = 6.0 Hz, 1H), 4.57 (s, 1H), 3.66−3.41 (b, 4H), 3.56 (d, J = 3.1
HRMS (ESI+) m/z 526.3612 (526.3621 calcd for C H N O Na [M
+
29
49
3
4
Hz, 1H), 2.12 (b, 4H), 1.68 (s, 6H); 13C NMR (150 MHz, D O) δ
+
Na] ).
E/Z)-5-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-
-ylidene)-1-methyl-3-octylpyrimidine-2,4,6(1H,3H,5H)-trione
2
2
3
08.4, 155.1, 137.6, 103.7, 72.3, 69.1, 52.6, 46.6, 24.5, 22.7; IR (KBr)
410, 3090, 3036, 2985, 2908, 2584, 2411, 1715, 1667, 1574, 1490,
(
1
(
63). Following general procedure A, the title compound was obtained
1471, 1412, 1393, 1371, 1346, 1323, 1289, 1263, 1216, 1198, 1162,
1
−1
as a dark purple solid (90 mg, 65%): H NMR (500 MHz, CD Cl ) δ
1
1134, 1116, 1066, 1035, 1006 cm ; HRMS (ESI+) m/z 316.1154
2
2
+
+
2.53 (dd, J = 28.6, 1.3 Hz, 1H), 7.29 (dd, J = 12.2, 1.2 Hz, 1H), 7.06
(316.1161 calcd for C15H19NO Na [M + Na] ).
5
(
s, 1H), 6.81 (ddd, J = 12.3, 2.8, 1.5 Hz, 1H), 6.08 (t, J = 12.3 Hz,
2,2-Dimethyl-4-oxo-5-(2-oxo-5-(piperidin-1-ium-1-yl)-
cyclopent-3-en-1-yl)-4H-1,3-dioxin-6-olate (72). Following gen-
1
1
H), 3.93−3.81 (m, 2H), 3.49 (dq, J = 21.1, 7.2 Hz, 4H), 3.27 (d, J =
4.2 Hz, 3H), 1.63−1.52 (m, 2H), 1.30 (m, 16H), 0.88 (td, J = 7.0, 2.0
eral procedure B, the title compound was obtained as a white solid
1
13
(108 mg, 88%): H NMR (500 MHz, D O) δ 7.86 (dd, J = 6.1, 1.8 Hz,
Hz, 3H); C NMR (125 MHz, CD Cl ) δ 165.7, 165.4, 163.6, 163.2,
2
2
2
1
H), 6.65 (dd, J = 6.1, 1.4 Hz, 1H), 4.62−4.52 (m, 1H), 3.58−2.94
1
4
1
1
8
57.6, 152.1, 151.6, 146.7, 146.7, 138.4, 103.2, 98.4, 52.5, 44.7, 42.1,
2.0, 32.4, 30.0, 29.9, 29.9, 29.8, 28.8, 28.7, 28.5, 28.4, 27.6, 27.5, 23.2,
4.8, 14.4, 12.7. IR (ATR) 2925, 2854, 1692, 1621, 1596, 1557, 1495,
461, 1425, 1406, 1371, 1352, 1261, 1229, 1203, 1150, 1074, 989, 909,
38, 777, 729, 685; HRMS (ESI+) m/z 428.2524 (428.2525 calcd for
13
(m, 4H), 2.24−1.71 (m, 6H), 1.67 (s, 6H); C NMR (125 MHz,
D O) δ 208.4, 154.5, 137.6, 103.7, 73.0, 70.7, 44.3, 24.5, 23.1, 21.1; IR
2
(
1
KBr) 3420, 3049, 2989, 2968, 2940, 2877, 2645, 2327, 2274, 1717,
682, 1576, 1521, 1469, 1446, 1413, 1375, 1365, 1345, 1330, 1321,
1291, 1261, 1235, 1215, 1201, 1190, 1179, 1149, 1116, 1081, 1048,
+
+
C H N O Na [M + Na] ).
22
35
3
4
−1
1
C
038, 1005 cm ; HRMS (ESI+) m/z 330.1318 (330.1317 calcd for
5
-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-1-yli-
+
+
dene)-1,3-diphenylpyrimidine-2,4,6(1H,3H,5H)-trione (65). Fol-
1
6
H21NO Na [M + Na] ). Because of it sparing solubility in D O
5
2
lowing general procedure A, the title compound was obtained as a
and reversion to 17 in organic solvents, the structure of 72 was
confirmed by single-crystal X-ray analysis. The crystal structure data
for 2,2-dimethyl-4-oxo-5-(2-oxo-5-(piperidin-1-ium-1-yl)cyclopent-
3-en-1-yl)-4H-1,3-dioxin-6-olate (72) can be obtained free of charge
from the Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif CCDC 844845.
1
purple solid (371 mg, 86%): H NMR (600 MHz, CD Cl ) δ 12.19 (s,
2
2
1
H), 7.52−7.24 (m, 11H), 7.02 (s, 1H), 6.92 (dd, J = 12.6, 1.5 Hz,
1
H), 6.16 (t, J = 12.4 Hz, 1H), 3.50 (dq, J = 36.5, 7.3 Hz, 4H), 1.30
(
dt, J = 10.2, 7.2 Hz, 6H); 13C NMR (150 MHz, CD Cl ) δ 165.1,
2 2
1
1
63.2, 158.7, 153.2, 151.2, 146.3, 136.7, 136.3, 135.6, 129.0, 129.0,
28.9, 128.8, 128.5, 128.2, 128.0, 103.9, 96.5, 52.2, 44.5, 14.1, 12.2.
5
-(2-(Diethylammonio)-5-oxocyclopent-3-en-1-yl)-2,2-di-
methyl-4-oxo-4H-1,3-dioxin-6-olate (73). Following general
IR(ATR) 3398, 2976, 2927, 1691, 1623, 1583, 1491, 1453, 1430, 1367,
−
1
procedure B, the title compound was obtained as a white solid (101
1
348, 1254, 1223, 1181, 1115, 1071, 986, 958, 883, 751, 692 cm ;
1
+
mg, 68%): H NMR (600 MHz, D O) δ 7.68 (dd, J = 6.1, 1.9 Hz, 1H),
HRMS (ESI+) m/z 454.1735 (454.1743 calcd for C H N O Na [M
2
25
25
3
4
+
6.55 (dt, J = 6.1, 1.4 Hz, 1H), 4.72−4.69 (m, 1H), 3.49 (d, J = 3.6 Hz,
+
Na] ).
1
H), 3.24 (b, J = 72.0 Hz, 4H), 1.54 (s, 6H), 1.22 (t, J = 7.3 Hz, 6H);
5
-((2Z,4E)-5-(Diethylamino)-2-hydroxypenta-2,4-dien-1-yli-
1
3
C NMR (150 MHz, D O) δ 208.2, 155.1, 138.0, 103.7, 72.6, 66.6,
dene)-1,3-bis(4-methoxyphenyl)pyrimidine-2,4,6(1H,3H,5H)-
2
trione (67). Following general procedure A, the title compound was
obtained as a purple solid (398 mg, 81%): H NMR (600 MHz,
44.1, 24.5, 9.3; IR (KBr) 3409, 3071, 2992, 2956, 2916, 2589, 2439,
1714, 1673, 1572, 1513, 1487, 1475, 1460, 1416, 1376, 1339, 1287,
1
−1
CD Cl ) δ 12.21 (s, 1H), 7.35 (d, J = 12.1 Hz, 1H), 7.17 (dd, J = 19.5,
1261, 1233, 1215, 1198, 1182, 1161, 1148, 1121, 1047, 1030 cm ;
2
2
+
8
1
.8 Hz, 4H), 7.03 (s, 1H), 6.97 (t, J = 9.1 Hz, 4H), 6.90 (dd, J = 12.7,
.5 Hz, 1H), 6.14 (t, J = 12.3 Hz, 1H), 3.83 (d, J = 3.4 Hz, 6H), 3.51
HRMS (ESI+) m/z 318.1313 (318.1317 calcd for C H NO Na [M
15
21
5
+
+ Na] ). The crystal structure data for 5-(2-(diethylammonio)-5-
oxocyclopent-3-en-1-yl)-2,2-dimethyl-4-oxo-4H-1,3-dioxin-6-olate
13
(
dq, J = 28.3, 7.2 Hz, 4H), 1.34−1.27 (m, 6H); C NMR (125 MHz,
K
dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
7
3.36−3.21 (m, 6H), 3.18 (s, 2H), 1.30 (t, J = 7.3 Hz, 6H); 13C NMR
(
73) has been previously reported and can be obtained free of charge
from the Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif CCDC 977459.
-(2-(Benzyl(methyl)ammonio)-5-oxocyclopent-3-en-1-yl)-
,2-dimethyl-4-oxo-4H-1,3-dioxin-6-olate (74). Following gen-
eral procedure B, the title compound was obtained as a white solid
137 mg, 80%): H NMR (500 MHz, D O) δ 7.86 (s, 1H), 7.51 (m,
H), 6.69 (dd, J = 6.1, 1.9 Hz, 1H), 4.22 (s, 1H), 3.76 (d, J = 3.6 Hz,
(150 MHz, D O) δ 208.5, 164.6, 163.7, 154.0, 138.0, 85.6, 66.5, 66.5,
2
46.4, 44.4, 44.4, 28.0, 27.2, 9.2; IR (KBr) 3052, 2986, 2972, 2919,
2742, 2660, 2502, 1727, 1674, 1667, 1614, 1599, 1578, 1517, 1477,
1435, 1397; HRMS (ESI+) m/z 330.1433 (330.1430 calcd for
5
2
+
+
C H N O Na [M +Na] ). The crystal structure data for 5-(2-
15
21
3
4
1
(
5
1
(diethylammonio)-5-oxocyclopent-3-en-1-yl)-1,3-dimethyl-2,6-
dioxo-1,2,3,6-tetrahydropyrimidin-4-olate (78) can be obtained free
of charge from the Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif CCDC 1026491.
2
13
H), 2.87 (s, 3H), 2.73 (s, 2H), 1.67 (m, 6H); C NMR (125 MHz,
D O) δ 208.1, 138.04, 130.6, 130.2, 129.6, 129.6, 129.4, 129.2, 129.0,
2
1
2
1
05.0, 103.8, 52.3, 32.0, 30.2, 25.1, 24.5; IR (KBr) 3080, 3037, 2988,
938, 2901, 2646, 2461, 1726, 1717, 1673, 1576, 1498, 1476, 1458,
415, 1375, 1349, 1290, 1262, 1212, 1199, 1173, 1159, 1120, 1040
1,3-Dimethyl-2,6-dioxo-5-(2-oxo-5-(1,2,3,4-tetrahydroiso-
quinolin-2-ium-2-yl)cyclopent-3-en-1-yl)-1,2,3,6-tetrahydro-
pyrimidin-4-olate (79). Following general procedure B, the title
−
1
1
cm ; HRMS (ESI+) m/z 366.1320 (366.1317 calcd for
C H NO Na [M + Na] ). Because of its sparing solubility in
D O and reversion to 28 in organic solvents, the structure of 74 was
confirmed by single crystal X-ray analysis. The crystal structure data
for 5-(2-(benzyl(methyl)ammonio)-5-oxocyclopent-3-en-1-yl)-2,2-
dimethyl-4-oxo-4H-1,3-dioxin-6-olate (74) can be obtained free of
charge from the Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif CCDC 851860.
compound was obtained as a white solid (320 mg, 87%): H NMR
+
+
(600 MHz, D O) δ 7.84 (dd, J = 6.3, 1.9 Hz, 1H), 7.20−7.00 (m, 3H),
19
21
5
2
6.89−6.75 (m, 1H), 6.55 (dd, J = 6.2, 1.9 Hz, 1H), 4.59 (dt, J = 3.8,
2.0 Hz, 1H), 4.45−4.29 (m, 2H), 3.78 (d, J = 3.6 Hz, 1H), 3.67 (dt, J =
11.9, 5.7 Hz, 1H), 3.57 (dt, J = 5.5, 2.0 Hz, 1H), 3.19−2.78 (m, 8H);
2
13
C NMR (125 MHz, D O) δ 208.0, 164.4, 163.6, 153.9, 153.7, 137.8,
2
130.2, 128.9, 128.7, 128.4, 128.0, 126.8, 126.5, 85.5, 67.8, 51.3, 47.7,
45.8, 28.0, 27.1. IR (ATR) 3006, 2989, 1716, 1668, 1568, 1435, 1374,
−1
2,2-Dimethyl-4-oxo-5-(2-oxo-5-(1,2,3,4-tetrahydroisoquino-
1318, 1275, 1260, 1187, 1062, 967, 907, 824, 764, 750 cm ; HRMS
+
lin-2-ium-2-yl)cyclopent-3-en-1-yl)-4H-1,3-dioxin-6-olate (75).
Following general procedure B, the title compound was obtained as
a white solid (151 mg, 85%): H NMR (500 MHz, D O) δ 7.96 (dd, J
(ESI+) m/z 390.1418 (390.1430 calcd for C H N O Na [M +
Na] ).
20
21
3
4
+
1
2
2-(2-(Furan-2-ylmethylene)-3-oxo-2,3-dihydro-1H-inden-1-
=
6.1, 2.0 Hz, 1H), 7.37−7.27 (m, 3H), 7.21−7.15 (m, 1H), 6.68 (dd,
J = 6.2, 1.9 Hz, 1H), 4.71 (s, 1H), 3.70 (d, J = 3.4 Hz, 1H), 3.62 (dq, J
12.3, 6.3 Hz, 1H), 3.54 (t, J = 6.6 Hz, 1H), 3.21 (q, J = 6.4 Hz, 2H),
ylidene)malononitrile (37). Following the procedure outlined by
2
7
Bello et al., the title compound was isolated as a bright orange solid
1
=
(882 mg, 81%): H NMR (500 MHz, CDCl ) δ 8.73−8.68 (m, 2H),
3
13
3.13 (t, J = 6.4 Hz, 1H), 3.02 (t, J = 6.7 Hz, 1H), 1.67 (s, 6H);
C
8.57 (s, 1H), 7.93 (dd, J = 7.5, 1.5 Hz, 1H), 7.84 (d, J = 1.6 Hz, 1H),
7.82−7.74 (m, 2H), 6.80−6.75 (m, 1H); C NMR (125 MHz,
CDCl ) δ 187.1, 160.5, 150.9, 150.2, 139.8, 137.3, 135.3, 134.8, 130.4,
13
NMR (125 MHz, D O) δ 207.3, 155.2, 137.6, 133.1, 128.7, 128.2,
2
1
2
1
1
1
28.0, 127.7, 127.0, 126.8, 126.6, 103.7, 69.5, 51.4, 47.9, 44.8, 41.6,
5.1, 24.5; IR (KBr) 3433, 3019, 2994, 2944, 2722, 2509, 2400, 1926,
726, 1667, 1568, 1504, 1479, 1457, 1440, 1426, 1411, 1394, 1373,
346, 1323, 1288, 1275, 1259, 1231, 1200, 1181, 1152, 1115, 1087,
3
127.3, 125.4, 124.4, 124.0, 115.5, 114.2, 113.8, 71.2. IR (ATR): 3166,
3147, 3129, 3079, 2218, 1708, 1595, 1576, 1543, 1451, 1357, 1231,
−1
1146, 1091, 1025, 933, 764, 718 cm ; HRMS (EI+) m/z 272.0589
−1
+
070, 1056, 1026, 1008 cm ; HRMS (ESI+) m/z 378.1314 (378.1317
(272.0586 calcd for C H N O [M] ).
17
8
2
2
+
+
calcd for C H NO Na [M +Na] ). Because of its sparing solubility
in D O and reversion to 29 in organic solvents, the structure of 75 was
3-(Diethylamino)-1-(furan-2-yl)-9-oxo-2,9-dihydro-1H-
indeno[2,1-c]pyridine-4-carbonitrile (38). Following general
20
21
5
2
confirmed by single crystal X-ray analysis. The crystal structure data
for 2,2-dimethyl-4-oxo-5-(2-oxo-5-(1,2,3,4-tetrahydroisoquinolin-2-
ium-2-yl)cyclopent-3-en-1-yl)-4H-1,3-dioxin-6-olate (75) can be
obtained free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif CCDC 844846.
procedure A, the title compound was isolated as a dark blue solid
1
(332 mg, 96%): H NMR (600 MHz, CD
Cl
2
) δ 8.36 (d, J = 7.6 Hz,
2
1H), 7.61−7.40 (m, 4H), 7.31 (s, 1H), 6.95 (d, J = 12.8 Hz, 1H), 6.32
(s, 1H), 5.33 (s, 1H), 3.59 (dq, J = 29.4, 7.3 Hz, 4H), 1.36 (dt, J =
14.6, 7.3 Hz, 6H); 13C NMR (125 MHz, CD
Cl ) δ 191.7, 160.0,
2 2
1
,3-Dimethyl-2,6-dioxo-5-(2-oxo-5-(pyrrolidin-1-ium-1-yl)-
159.8, 152.8, 148.4, 141.1, 136.6, 133.7, 132.2, 127.3, 123.8, 122.1,
118.2, 118.1, 113.4, 106.3, 53.2, 45.7, 14.6, 12.9. IR(ATR): 3325, 2979,
2935, 2874, 2196, 2179, 1666, 1616, 1602, 1579, 1498, 1436, 1367,
cyclopent-3-en-1-yl)-1,2,3,6-tetrahydropyrimidin-4-olate (76).
Following general procedure B, the title compound was obtained as a
white solid (235 mg, 77%): H NMR (600 MHz, D O) δ 7.85 (dd, J =
.8, 1.8 Hz, 1H), 6.67 (dd, J = 6.3, 1.6 Hz, 1H), 4.53 (d, J = 1.9 Hz,
1
−1
2
1344, 1243, 1185, 1111, 1068, 974, 912, 821, 759, 712 cm ; HRMS
+
5
1
2
1
2
7
(EI+) m/z 345.1483 (345.1477 calcd for C H N O [M] ).
21
19
3
2
H), 3.78 (d, J = 3.4 Hz, 1H), 3.48 (s, 4H), 3.20 (d, J = 61.7 Hz, 6H),
2,2′-(2-(Furan-2-ylmethylene)-1H-indene-1,3(2H)-diylidene)-
.06 (s, 4H); 13C NMR (125 MHz, D O) δ 208.7, 164.4, 163.7, 154.8,
dimalononitrile (39). Following the procedure outlined by Bello et
2
2
7
54.1, 137.7, 85.5, 69.1, 52.4, 46.9, 28.0, 27.2, 22.8; IR (ATR) 3006,
990, 2747, 2619, 1716, 1667, 1567, 1435, 1361, 1275, 1260, 1189,
50 cm ; HRMS (ESI+) m/z 328.1273 (328.1273 calcd for
al., the title compound was isolated as a bright orange solid (1.17 g,
1
91%): H NMR (600 MHz, CDCl
) δ 8.62 (d, J = 7.8 Hz, 1H), 8.51
3
−
1
(d, J = 7.8 Hz, 1H), 8.21 (s, 1H), 7.91−7.70 (m, 3H), 7.24 (d, J = 3.6
+
+
13
C H N O Na [M + Na] ).
5
Hz, 1H), 6.72 (dd, J = 3.9, 1.8 Hz, 1H); C NMR (150 MHz, CDCl )
3
1
19
3
4
1
,3-Dimethyl-2,6-dioxo-5-(2-oxo-5-(piperidin-1-ium-1-yl)-
δ 161.7, 160.7, 149.7, 148.6, 138.3, 136.6, 135.3, 134.6, 127.8, 127.4,
126.7, 126.2, 125.3, 115.3, 113.3, 113.1, 112.1, 78.8, 71.9. IR(ATR):
3139, 3121, 2222, 1608, 1551, 1527, 1460, 1396, 1349, 1025, 880, 772.
cyclopent-3-en-1-yl)-1,2,3,6-tetrahydropyrimidin-4-olate (77).
Following general procedure B, the title compound was obtained as a
white solid (259 mg, 81%): H NMR (600 MHz, D O) δ 7.69 (dd, J =
1
−1
2
715 cm ; HRMS (EI+) m/z 320.0693 (320.0698 calcd for C H N O
20
8
4
+
6
.2, 2.0 Hz, 1H), 6.50 (dd, J = 6.3, 1.9 Hz, 1H), 4.46−4.32 (m, 1H),
[M] ).
3
.71 (d, J = 3.6 Hz, 1H), 3.49−2.85 (m, 10H), 1.93−1.24 (m, 6H);
2-(4-Cyano-3-(diethylamino)-1-(furan-2-yl)-1,2-dihydro-9H-
indeno[2,1-c]pyridin-9-ylidene)malononitrile (40). Following
1
3
C NMR (125 MHz, D O) δ 208.7, 164.4, 163.8, 154.3, 154.1, 137.5,
2
8
2
1
3
6.1, 70.7, 67.8, 50.8, 44.7, 23.0, 22.1, 21.4, 21.1. IR(ATR) 3006, 2989,
918, 2861, 1718, 1673, 1604, 1575, 1473, 1440, 1370, 1319, 1275,
general procedure A, the title compound was isolated as a dark blue
1
solid (315 mg, 80%): H NMR (600 MHz, CD
Cl
) δ 8.19−8.09 (m,
2
2
−1
260, 1191, 1153, 1117, 1016, 951, 707 cm ; HRMS (ESI+) m/z
2H), 7.42−7.34 (m, 3H), 6.49 (s, 1H), 6.36−6.30 (m, 2H), 6.20 (d, J
+
=
42.1424 (324.1430 calcd for C H N O Na [M + Na] ).
= 3.3 Hz, 1H), 3.63 (ddt, J = 42.7, 15.2, 7.5 Hz, 4H), 1.31 (t, J = 7.1
16
21
3
4
Hz, 6H); 13C NMR (125 MHz, CD
Cl ) δ 158.1, 155.6, 155.2, 152.9,
2 2
5
-(2-(Diethylammonio)-5-oxocyclopent-3-en-1-yl)-1,3-di7-
methyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate (78).
Following general procedure B, the title compound was obtained as
a white solid (142 mg, 92%): H NMR (600 MHz, D O) δ 7.84 (dd, J
=
144.0, 137.9, 137.6, 131.4, 130.8, 124.0, 123.1, 119.2, 117.5, 116.9,
111.0, 108.4, 48.0, 46.2, 30.3, 13.6. IR(ATR) 3312, 3108, 2937, 2206,
2188, 1581, 1546, 1504, 1396, 1380, 1347, 1242, 1219, 1164, 1143,
1
2
−1
6.1, 1.9 Hz, 1H), 6.71 (ddd, J = 6.1, 1.9, 0.8 Hz, 1H), 4.83 (d, J = 1.8
1079, 1015, 920, 882, 749 cm ; HRMS (EI+) m/z 393.1583
+
Hz, 1H), 3.88 (d, J = 3.6 Hz, 1H), 3.39 (dq, J = 14.6, 7.4 Hz, 2H),
(393.1590 calcd for C H N O [M] ).
24
19
5
L
dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
1
1
,3-Dibutyl-5-(furan-2-ylmethylene)pyrimidine-2,4,6-
solid (1.32 g, 77%): H NMR (600 MHz, CDCl ) δ 8.57 (d, J = 3.8
3
(
1H,3H,5H)-trione (58). Following the procedure outlined by Deb
Hz, 1H), 8.49 (s, 1H), 7.81 (d, J = 1.5 Hz, 1H), 7.39 (dd, J = 13.3, 8.6
Hz, 4H), 7.17 (dd, J = 12.5, 8.6 Hz, 4H), 6.70−6.61 (m, 1H);
NMR (150 MHz, CDCl ) δ 162.2, 160.7, 151.7, 151.2, 150.4, 142.8,
135.2, 135.1, 133.3, 133.0, 130.2, 130.0, 130.0, 129.8, 129.7, 115.8,
110.8; IR (ATR) 3136, 3118, 2925, 2855, 1735, 1672, 1564, 1489,
1454, 1418, 1399, 1346, 1324, 1233, 1154, 1087, 1028, 1014, 949, 920,
25
13
and Bhuyan, the title compound was obtained as a pale yellow solid
10.93g, 63%): H NMR (500 MHz, CDCl ) δ 8.62 (d, J = 3.8 Hz,
H), 8.41 (d, J = 0.7 Hz, 1H), 7.83 (dd, J = 1.7, 0.6 Hz, 1H), 6.72
C
1
(
1
(
4
3
3
ddd, J = 3.8, 1.6, 0.8 Hz, 1H), 4.04−3.87 (m, 4H), 1.75−1.51 (m,
13
H), 1.50−1.29 (m, 4H), 0.95 (td, J = 7.4, 3.4 Hz, 6H); C NMR
−1
(
125 MHz, CDCl ) δ 162.4, 160.8, 151.4, 151.1, 150.4, 141.0, 128.0,
826, 801, 783, 751 cm ; HRMS (ESI+) m/z 449.0066 (449.0072
3
+
+
1
3
1
7
15.2, 112.1, 42.5, 41.8, 30.4, 30.3, 20.4, 20.4, 14.0, 14.0. IR (ATR)
120, 2957, 2933, 2873, 1724, 1659, 1578, 1445, 1428, 1409, 1376,
308, 1250, 1203, 1157, 1128, 1091, 1036, 1022, 962, 915, 884, 791,
calcd for C H N O Cl Na [M + Na] ).
21 12 2 4 2
ASSOCIATED CONTENT
■
* Supporting Information
Additional experimental details, spectroscopic data, XRD
atomic distance measurements, and ORTEP plots of reported
crystal structures. This material is available free of charge via the
Internet at http://pubs.acs.org.
−1
60, 734 cm ; HRMS (ESI+) m/z 341.1479 (341.1477 calcd for
+
+
S
C H N O Na [M + Na] ).
7
5
1H,3H,5H)-trione (62). 1-methyl-3-octylpyrimidine-2,4,6-
1H,3H,5H)-trione (S1): A solution of methylamine−HCl (0.12 g,
.79 mmol) in anhydrous DCM (15 mL) was treated with n-octyl
isocyanate (0.30 mL, 1.70 mmol) under argon. Triethylamine (0.35
mL, 2.56 mmol) was then added, and the mixture was heated to reflux.
After 1 h, malonyl dichloride (0.17 mL, 1.70 mmol) was added under
argon and heated to reflux for an additional 1 h. The mixture was
cooled to rt and quenched with 1 N HCl. The crude product was
extracted with DCM (3 × 10 mL), washed with H O (10 mL), dried
over MgSO , and filtered. The solvent was removed in vacuo and the
product was purified by column chromatography (hexane/EtOAc =
:1 to 1:1) to afford clear oil (302 mg, 67%): H NMR (500 MHz,
1
22
2
4
-(Furan-2-ylmethylene)-1-methyl-3-octylpyrimidine-2,4,6-
(
(
1
AUTHOR INFORMATION
■
*
Corresponding Author
E-mail: javier@chem.ucsb.edu.
2
Notes
4
The authors declare no competing financial interest.
1
9
CDCl ) δ 3.91−3.78 (m, 2H), 3.65 (s, 2H), 3.29 (s, 3H), 1.62−1.52
3
ACKNOWLEDGMENTS
13
■
(
m, 2H), 1.34−1.18 (m, 10H), 0.86 (t, J = 7.0 Hz, 3H); C NMR
S.H. thanks UCSB LSAMP Bridge to the Doctorate (award no.
929836) for financial support. S.O., C.J.H., and J.R.A thank
the National Science Foundation (MRSEC program DMR-
1121053) and the Dow Material Institute for financial support.
We also thank Dr. Guang Wu (UCSB) for X-ray analysis.
(
125 MHz, CDCl ) δ 165.0, 164.7, 151.8, 42.4, 39.7, 32.0, 29.4, 29.3,
3
0
2
1
6
8.6, 28.2, 27.0, 22.8, 14.3. IR (ATR) 2956, 2924, 2855, 1685, 1519,
433, 1409, 1389, 1364, 1334, 1268, 1168, 1121, 1005, 936, 758, 723,
−
1
85 cm ; HRMS (EI+) m/z 254.1641 (254.1630 calcd for
+
+
C H N O [M] ). This material was subjected to the conditions
of Deb and Bhuyan to give the title compound as a pale yellow solid
13
22
2
3
2
5
1
(
228 mg, 83%): H NMR (500 MHz, CDCl ) δ 8.63 (d, J = 3.7 Hz,
3
REFERENCES
■
1H), 8.42 (s, 1H), 7.84 (d, J = 1.5 Hz, 1H), 6.72 (ddd, J = 3.9, 1.8, 0.9
(
1) Castagna, R.; Garbugli, M.; Bianco, A.; Perissinotto, S.; Pariani,
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1
3
1
1
2
1
1
.24 (m, 10H), 0.89−0.85 (m, 3H); C NMR (125 MHz, CDCl ) δ
3
(
1
(
2) Xie, X.; Mistlberger, G.; Bakker, E. J. Am. Chem. Soc. 2012, 134,
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62.7, 160.7, 151.4, 151.3, 150.4, 141.1, 128.1, 115.3, 111.9, 42.1, 32.0,
9.5, 29.4, 29.1, 28.3, 27.2, 22.8, 14.3. IR (ATR) 3145, 2915, 2851,
728, 1658, 1575, 1543, 1450, 1423, 1407, 1366, 1327, 1252, 1201,
166, 1129, 1115, 1095, 1029, 988, 962, 921, 882, 789, 756, 719 cm ;
HRMS (ESI+) m/z 355.1627 (355.1634 calcd for C H N O Na [M
Na] )
-(Furan-2-ylmethylene)-1,3-diphenylpyrimidine-2,4,6-
1H,3H,5H)-trione (64). Following the procedure out lined by Deb
and Bhuyan, the title compound was isolated as a bright yellow solid
1.22 g, 85%): H NMR (600 MHz, CDCl ) δ 8.66 (d, J = 3.9 Hz,
−1
+
18
24
2
4
+
+
(
5
(
25
(
1
2
2
1
014, 136, 2178. (c) Kumpfer, J. R.; Rowan, S. J. J. Am. Chem. Soc.
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(
3
1
7
H), 8.59 (s, 1H), 7.88 (d, J = 1.5 Hz, 1H), 7.56−7.41 (m, 6H), 7.36−
.30 (m, 4H), 6.71 (ddd, J = 3.9, 1.7, 0.8 Hz, 1H); 13C NMR (150
8.
(
6) For recent examples of photochromic compounds that operate
with visible light, see: (a) Beharry, A. A.; Sadovski, O.; Woolley, G. A.
J. Am. Chem. Soc. 2011, 133, 19684. (b) Bleger, D.; Schwarz, J.;
Brouwer, A. M.; Hecht, S. J. Am. Chem. Soc. 2012, 134, 20597.
c) Cnossen, A.; Hou, L.; Pollard, M. M.; Wesenhagen, P. V.; Browne,
MHz, CDCl ) δ 162.5, 151.3, 151.1, 142.4, 135.0, 134.7, 129.5, 129.4,
3
1
3
1
29.2, 129.1, 128.8, 128.6, 115.6, 111.4. IR (ATR) 3348, 3146, 3124,
070, 1736, 1668, 1570, 1490, 1455, 1416, 1356, 1326, 1236, 1199,
́
−1
149, 1030, 948, 882, 786, 691 cm ; HRMS (ESI+) m/z 381.0851
+
+
(
(
381.0851 calcd for C H N O Na [M + Na] ).
21 14 2 4
W. R.; Feringa, B. L. J. Am. Chem. Soc. 2012, 134, 17613. (d) Hatano,
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S.; Beharry, A. A.; Sadovski, O.; McCormick, T. M.; Babalhavaeji, A.;
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5
-(Furan-2-ylmethylene)-1,3-bis(4-methoxyphenyl)-
pyrimidine-2,4,6(1H,3H,5H)-trione (66). Following the procedure
25
out lined by Deb and Bhuyan, the title compound was isolated as a
bright yellow solid (1.46 g, 87%): H NMR (600 MHz, CDCl ) δ 8.66
1
3
(
(
(
1
1
2
1
4
d, J = 3.9 Hz, 1H), 8.57 (s, 1H), 7.86 (d, J = 1.6 Hz, 1H), 7.25−7.20
m, 4H), 7.04−6.98 (m, 4H), 6.70 (ddd, J = 4.0, 1.6, 0.8 Hz, 1H), 3.84
d, J = 2.6 Hz, 6H); 13C NMR (150 MHz, CDCl ) δ 162.8, 161.3,
3
59.9, 159.8, 151.3, 151.2, 151.0, 142.3, 129.7, 129.6, 129.3, 127.6,
27.2, 115.5, 114.8, 114.7, 111.6, 55.6. IR (ATR) 3139, 3116, 3002,
964, 2835, 1733, 1674, 1607, 1568, 1509, 1455, 1349, 1325, 1239,
156, 1027, 951, 828, 808, 779, 752 cm ; HRMS (ESI+) m/z
41.1049 (441.1063 calcd for C H N O Na [M + Na] ).
−1
+
+
23
18
2
6
1
,3-Bis(4-chlorophenyl)-5-(furan-2-ylmethylene)pyrimidine-
2
,4,6(1H,3H,5H)-trione (68). Following the procedure out lined by
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M.; Levitz, A. Dyes Pigments 2013, 99, 1107. (c) Mishra, A.; Behera, R.
25
Deb and Bhuyan, the title compound was isolated as a bright yellow
M
dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX

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dx.doi.org/10.1021/jo502206g | J. Org. Chem. XXXX, XXX, XXX−XXX