Spontaneous conversion of 3-alkyl-substituted 3-hydroperoxypyrrolidine-2,4- diones into 5-alkyl-5-hydroxyoxazolidin-4-ones

Article abstract of DOI:10.1246/cl.2011.1349

3-Hydroperoxypyrrolidine-2,4-diones substituted with an alkyl group at the 3-position were spontaneously transformed into 5-hydroxyoxazolidin-4-one derivatives at room temperature in air accompanied by the evolution of carbon monoxide.

Full text of DOI:10.1246/cl.2011.1349

doi:10.1246/cl.2011.1349
Published on the web November 12, 2011
1349
Spontaneous Conversion of 3-Alkyl-substituted 3-Hydroperoxypyrrolidine-2,4-diones
into 5-Alkyl-5-hydroxyoxazolidin-4-ones
Md. Aminul Haque, Hayato Ishikawa, and Hiroshi Nishino*
Department of Chemistry, Graduate School of Science and Technology, Kumamoto University,
2-39-1 Kurokami, Kumamoto 860-8555
(Received September 21, 2011; CL-110767; E-mail: nishino@sci.kumamoto-u.ac.jp)
3-Hydroperoxypyrrolidine-2,4-diones substituted with an
alkyl group at the 3-position were spontaneously transformed
into 5-hydroxyoxazolidin-4-one derivatives at room temperature
in air accompanied by the evolution of carbon monoxide.
colorless needles (mp 210 °C), however, the solid hydroperoxide
3a was not stable and gradually degraded in air at room
temperature, giving a colorless viscous liquid. We were very
interested in this spontaneous degeneration and scrutinized the
reaction.
1-Benzyl-3-hydroperoxy-3-methylpyrrolidine-2,4-dione (3a)
was prepared as follows. To a solution of the pyrrolidine-2,4-
dione 1a (1 mmol) in glacial acetic acid (25 mL), manganese(III)
acetate dehydrate (26.8 mg, 0.1 mmol) was added. The mixture
was stirred at room temperature in air for 2 h, and then the
reaction was quenched by adding water (25 mL) to the mixture.
The aqueous reaction mixture was extracted three times with
CH2Cl2 (30 mL) and the combined extract was washed with
water, then a saturated aqueous solution of sodium hydrogen
carbonate, dried over anhydrous magnesium sulfate, and con-
centrated to dryness. Although the product was almost pure, it
was further purified by silica gel flash column chromatography,
eluting with EtOAc/hexane (8:2 v/v), and recrystallized from
Et2O/hexane to give the hydroperoxide 3a in 94% yield as
colorless blocks, mp 78-79 °C.12,13
When the colorless solid 3a was kept in air in a glass vial at
room temperature, the solid 3a became a viscous liquid along
with the evolution of a gas.14 The liquid was purified by silica
gel column chromatography eluting with EtOAc/hexane (5:5
v/v), and the obtained crude colorless solid was recrystallized
from Et2O/hexane to give 4a as colorless needles that melted at
105 °C. Other detectable products were not isolated. In order to
deduce the structure of 4a, the spectroscopic data of 4a15 was
compared with those of 3a.13 An important characteristic of the
data was the fact that there were no keto-carbonyl groups in
the compound 4a and a ring methylene carbon (¤ 77.1) and a
ring quaternary carbon (¤ 99.6) were shifted downfield (high
frequency) compared to those of 3a (¤ 53.4 and 82.5,
respectively) in the 13C NMR spectrum. In fact, the molecular
weight of 4a was reduced m/z 28 from that of 3a in the MS.
Therefore, the structure of 4a must be 3-benzyl-5-hydroxy-5-
methyloxazolidin-4-one. The combustion analysis and HRMS
also supported this structure (Scheme 2). It was suggested that
the unique conversion must involve a rearrangement reaction
accompanied by the extrusion of gas.
Organic hydroperoxides are important not only as oxidation
intermediates,1 but also as organic oxidants.2 The peroxides are
also found in nature, some of which have several biological
actvities.3 In general, the oxygen-oxygen bond of peroxides is
weak (¦H°298 158-194 kJ mol¹1),4 and it is somewhat difficult
to synthesize and isolate peroxide compounds. Recently, we
reported a convenient peroxide synthesis using manganese(III)-
catalyzed aerobic oxidation.5 A mixture of 3-(2-oxoethyl)piper-
idine-2,4-diones and 1,1-diarylethenes underwent endoperoxi-
dation to produce structurally interesting trioxaaza[4.4.3]propel-
lanes.6 The aerobic oxidation of arylacetylenes with pentane-
2,4-dione gave the 1,2-dioxolane derivatives.7 On the other
hand, a similar reaction of cyclic amides such as barbituric
acids,6,8,9b 1,2-disubstituted pyrazolidine-3,5-diones,9 and 4-
hydroxy-1H-qinolin-2-ones,6,9b,10 afforded the corresponding
hydroperoxy derivatives. Very recently, we found a similar
endoperoxidation and hydroperoxidation of 3-alkyl-substituted
pyrrolidine-2,4-diones in the presence11 or absence12 of 1,1-
diarylethenes in connection with our aerobic oxidation study.
For example, the reaction of 1-benzyl-3-methylpyrrolidine-2,4-
dione (1a) gave the endoperoxide 2a in the presence of 1,1-
diphenylethene,11 while the hydroperoxide 3a was produced in
the absence of the alkene (Scheme 1).12 The endoperoxide 2a
was very stable and recrystallized from EtOAc/hexane as
In order to scrutinize the reaction, other hydroperoxypyrro-
lidinediones 3b-3k were prepared and kept in air at room
temperature. Surprisingly, all the hydroperoxypyrrolidinediones
degenerated, and the corresponding hydroxyoxazolidin-4-ones
4b-4i were isolated after chromatographic separation except for
the N-tert-butyl-protected hydroperoxypyrrolidinediones 3j and
3k (Scheme 2 and Table 1). In the case of 3j and 3k, a complex
mixture was obtained after 72 h and no products could be
isolated (Entries 13 and 14). Since the transformation of the
hydroperoxides 3a and 3c into the oxazolidinones 4a and 4c was
Scheme 1. Aerobic oxidation of pyrrolidinedione 1a.
Chem. Lett. 2011, 40, 1349-1351
© 2011 The Chemical Society of Japan
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1350
Scheme 2. Conversion of hydroperoxypyrrolidinediones 3
into hydroxyoxazolidinones 4.
Table 1. Conversion of hydroperoxypyrrolidinediones 3 into
hydroxyoxazolidin-4-ones 4a
Entry
Pyrrolidinedione
Time/h
Oxazolidine/%b
Scheme 3. Mechanistic pathway of conversion from 3a to 4a.
1
2c
3
3a
3a
3b
3c
3c
3c
3d
3e
3f
3g
3h
3i
3j
3k
72
2
72
96
24
2
24
24
24
48
48
48
72
72
4a (30)
4a (40)
4b (60)
4c (20)
4c (35)
rearragement to give the 5-hydroxy-1,3-oxazinane-4,6-dione
intermediate B.19 The hydroxyoxazinanedione B would sponta-
neously ring-open to generate an unstable oxomethanide C
followed by the release of carbon monoxide and subsequent
recyclization of D, affording the hydroxyoxazolidinone 4a. The
pathway is briefly depicted in Scheme 3. Unfortunately, the
intermediates have not been isolated at this moment.
In summary, the hydroperoxypyrrolidinediones 3 were
relatively stable in acetic acid, however, when the hydro-
peroxides 3 were once isolated and kept in air at room
temperature, the hydroperoxides 3 spontaneously underwent
degradation to afford the very stable hydroxyoxazolidinones 4.
The transformation of the hydroperoxides 3 depended on the
N-protective group, that is, only the N-butyl group gave a good
result, but the N-benzyl and N-isopropyl groups did not. The N-
tert-butyl group was quite complicated. In order to control the
production of the hydroxyoxazolidinones 4, further exploration
of the reaction is currently in progress.
4
5d
6c
7
4c (60)
4d (quant)
4e (quant)
4f (quant)
4g (40)
4h (45)
4i (39)
8
9
10
11
12
13
14
complex mixture
complex mixture
aThe hydroperoxypyrrolidinedione 3 (0.5 mmol) was stored in
air at room temperature. bThe yield based on the hydro-
peroxypyrrolidinedione 3 used. cThe hydroperoxide (0.5
mmol) was heated under reflux in CHCl3 (10 mL) for 2 h.
dThe reactant was heated at 100 °C without any solvent for
24 h.
References and Notes
1
a) The Chemistry of Peroxides, ed. by S. Patai, Wiley-Interscience,
New York, 1983. b) H. Klenk, P. H. Götz, R. Siegmeier, W. Mayr,
Peroxy Compounds, Organic in Ullmann’s Encyclopedia of
Industrial Chemistry, Wiley-VCH, Weinheim, 2000. doi:10.1002/
14356007.a19_199. c) The Chemistry of Free Radicals: Peroxyl
Radicals, ed. by Z. B. Alfassi, Wiley, New York, 1997. d) C. A.
Rouzer, L. J. Marnett, Chem. Rev. 2003, 103, 2239. e) H. Leisch, K.
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not very efficient, the conversion was carried out at reflux
temperature in CHCl3 for 2 h to afford the oxazolidinones 4a and
4c in much better yields (Entries 2 and 6).
The degradation pathway was so mysterious. However,
there were two hints to elucidate the pathway. One was that the
hydroperoxy group of 3a formed a hydrogen bond with the keto-
carbonyl group. In fact, the hydroperoxy group appeared at
¤ 11.28 in the 1H NMR spectrum.16 In addition, the crystal
structure of 4-benzyl-4-hydroperoxy-1,2-diphenylpyrazolidine-
3,5-dione showed that the distance between the carbonyl oxygen
and the terminal hydroperoxy oxygen was 2.705 ¡, which means
that the hydroperoxy group is stabilized by the formation of
hydrogen bonding.9b The other hint was that a gas was evolved
during the degradation. In order to determine the type of gas, we
checked the gas using a short-term quick-measuring detector
tube17 and the evolved gas proved to be carbon monoxide.
Accordingly, we deduced the degradation process as follows.
The nucleophilic addition of the hydrogen-bonded hydroperoxy
group to the keto-carbonyl group might form the Criegee-type
intermediate A,18 which must undergo the Baeyer-Villiger
2
3
a) W. Adam, C. R. Saha-Möller, P. A. Ganeshpure, Chem. Rev.
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4
5
Review of the manganese(III)-catalyzed aerobic oxidation: H.
Nishino, in Bioactive Heterocycles I, ed. by S. Eguchi, Springer,
Berlin, 2006, pp. 39-76.
6
7
K. Asahi, H. Nishino, Eur. J. Org. Chem. 2008, 2404.
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Chem. Lett. 2011, 40, 1349-1351
© 2011 The Chemical Society of Japan
www.csj.jp/journals/chem-lett/

1351
a
b
8
9
C.-Y. Qian, H. Nishino, K. Kurosawa, J. D. Korp, J. Org. Chem.
1993, 58, 4448.
a) Md. T. Rahman, H. Nishino, Tetrahedron 2003, 59, 8383. b)
Md. T. Rahman, H. Nishino, Org. Lett. 2003, 5, 2887.
J = 9.0 Hz, PhCH2 ), 4.28 (1H, d, J = 9.0 Hz, PhCH2 ), 3.60 (1H,
br s, OH), 1.82 (2H, m, CH2), 1.37 (1H, m, CH2), 1.28 (1H, m,
CH2), 0.86 (3H, t, J = 4.5 Hz, Me); 13C NMR (CDCl3): ¤ 169.0
(C=O), 134.7, 129.0, 128.2, 127.8 (arom C), 101.4 (C-5), 77.6
(C-2, CH2), 44.6 (PhCH2), 38.4, 16.5 (CH2), 13.9 (Me). FAB
HRMS (acetone/NBA/NaI) m/z: calcd for C13H17NO3Na
258.1106 (M + Na); found 258.1065.
10 R. Kumabe, H. Nishino, Tetrahedron Lett. 2004, 45, 703.
11 Md. A. Haque, H. Nishino, Heterocycl. Commun. 2010, 16, 209.
12 M. A. Haque, H. Nishino, Synth. Commun. 2012, 42, 608.
13 1-Benzyl-3-hydroperoxy-3-methylpyrrolidine-2,4-dione
(3a):
3-Butyl-5-hydroxy-5-methyloxazolidin-4-one (4d): Yield (quant);
Rf = 0.45 (EtOAc:hexane = 8:2 v/v); colorless liquid; IR (CHCl3):
¯ 3585-3100 (OH), 1710 (C=O); 1H NMR (CDCl3): ¤ 5.03 (1H, d,
J = 2.1 Hz, CH2), 4.82 (1H, d, J = 2.1 Hz, CH2), 4.44 (1H, br s,
OH), 3.30 (1H, m, CH2), 3.22 (1H, m, CH2), 1.52 (3H, s, CH3),
1.47 (2H, m, CH2), 1.28 (2H, m, CH2), 0.87 (3H, t, J = 6.0 Hz,
Me); 13C NMR (CDCl3): ¤ 169.2 (C=O), 99.5 (C-5), 77.0 (C-2,
CH2), 40.5, 29.4, 19.9 (CH2), 23.0, 13.6 (Me). FAB HRMS
(acetone/NBA/NaI) m/z: calcd for C8H15NO3Na 196.0950
(M + Na); found 196.0923.
Yield (221.1 mg, 94%); Rf = 0.67 (EtOAc:hexane = 8:2 v/v);
colorless blocks (from Et2O/hexane); mp 78-79 °C; IR (CHCl3):
¯ 3400-3000 (OOH), 1786, 1666 (C=O); 1H NMR (CDCl3): ¤
11.28 (1H, s, OOH), 7.36-7.27 (5H, m, arom H), 4.79 (1H, d,
J = 14.7 Hz, CH2), 4.64 (1H, d, J = 14.7 Hz, CH2), 3.75 (2H, s,
CH2), 1.39 (3H, s, Me); 13C NMR (CDCl3): ¤ 204.1 (C-4, C=O),
171.3 (C-2, C=O), 134.0, 129.1, 128.4, 128.3 (arom C), 82.5 (C-3),
53.4 (C-5, CH2), 46.8 (PhCH2), 16.7 (Me). FAB HRMS (acetone/
NBA) m/z: calcd for C12H14NO4 236.0923 (M + H); found
236.0935.
3-Butyl-5-ethyl-5-hydroxyoxazolidin-4-one (4e): Yield (quant);
Rf = 0.33 (EtOAc:hexane = 6:4 v/v); colorless liquid; IR (CHCl3):
¯ 3600-3100 (OH), 1708 (C=O); 1H NMR (CDCl3): ¤ 5.12 (1H, d,
J = 3.3 Hz, CH2), 4.92 (1H, d, J = 3.3 Hz, CH2), 4.22 (1H, br s,
14 The solid 3a also changed into viscous liquid under an argon
atmosphere, even when stored in a refrigerator at ¹20 °C.
15 3-Benzyl-5-hydroxy-5-methyloxazolidin-4-one (4a): Yield (40%);
Rf = 0.32 (EtOAc:hexane = 6:4 v/v); colorless needles (from
Et2O/hexane); mp 105 °C; IR (KBr): ¯ 3400-3100 (OH), 1678
(C=O); 1H NMR (CDCl3): ¤ 7.34-7.22 (5H, m, arom H), 5.00 (1H,
d, J = 3.3 Hz, CH2), 4.75 (1H, d, J = 3.3 Hz, CH2), 4.63 (1H, br s,
OH), 4.59 (1H, d, J = 15.0 Hz, CH2), 4.38 (1H, d, J = 15.0 Hz,
CH2), 1.63 (3H, s, Me); 13C NMR (CDCl3): ¤ 169.5 (C=O), 134.7,
128.9, 128.2, 127.9 (arom C), 99.6 (C-5), 77.1 (C-2, CH2), 44.7
(PhCH2), 23.0 (Me). FAB HRMS (acetone/NBA/NaI) m/z: calcd
for C11H13NO3Na 230.0793 (M + Na); found 230.0800. Anal.
Calcd for C11H13NO3: C, 63.76; H, 6.32; N, 6.76%. Found: C,
63.80; H, 6.48; N, 6.79%.20
16 The hydroperoxy group of the cyclic amides normally appeared at
¤ 8.6-9.8, for example, bis(hydroperoxyethyl)barbituric acids (¤
8.6-9.2),6,8 bis(hydroperoxyethyl)pyrazolidinediones (¤ 8.8-9.8),9a
and bis(hydroperoxyethyl)quinolinediones (¤ 9.2).10
17 The short-term quick-measuring detector tube was commercially
available from the GASTEC Corporation, Japan, and a Polytec IV
No. 27 detector tube was used to detect the gas.
18 a) L. Lopez, G. M. Farinola, A. Nacci, S. Sportelli, Tetrahedron
1998, 54, 6939. b) W. F. Brill, J. Chem. Soc., Perkin Trans. 2 1984,
621. c) R. K. Haynes, S. C. Vonwiller, J. Chem. Soc., Chem.
Commun. 1990, 449.
19 a) C. H. Hassall, Org. React. 1957, 9, 73. b) G. R. Krow, Org.
React. 1993, 43, 251. c) G. H. Anderson, J. G. Smith, Can. J.
Chem., 1968, 46, 1553; G. H. Anderson, J. G. Smith, Can. J.
Chem., 1968, 46, 1561. d) R. M. Goodman, Y. Kishi, J. Am. Chem.
Soc. 1998, 120, 9392. e) C. M. Crudden, A. C. Chen, L. A.
Calhoun, Angew. Chem., Int. Ed. 2000, 39, 2851.
a
b
OH), 3.44 (1H, m, CH2), 3.26 (1H, m, CH2), 1.88 (2H, m, CH2),
1.54 (2H, m, CH2), 1.33 (2H, m, CH2), 0.96 (3H, t, J = 7.5 Hz,
Me), 0.92 (3H, t, J = 7.8 Hz, Me); 13C NMR (CDCl3): ¤ 168.8
(C=O), 101.9 (C-5), 78.2 (C-2, CH2), 40.4 (CH2), 29.4 (2CH2),
19.9 (CH2), 13.5, 7.4 (Me). FAB HRMS (acetone/NBA/NaI) m/z:
calcd for C9H17NO3Na 210.1106 (M + Na); found 210.1110.
3,5-Dibutyl-5-hydroxyoxazolidin-4-one (4f): Yield (quant); Rf =
0.39 (EtOAc:hexane = 5:5 v/v); colorless liquid; IR (CHCl3):
¯ 3585-3100 (OH), 1705 (C=O); 1H NMR (CDCl3): ¤ 5.10 (1H, br
s, OH), 5.04 (1H, d, J = 3.3 Hz, CH2), 4.83 (1H, d, J = 3.3 Hz,
CH2), 3.34 (1H, m, CH2), 3.17 (1H, m, CH2), 1.81 (2H, m, CH2),
1.47 (2H, m, CH2), 1.26 (6H, m, 3CH2), 0.87 (3H, t, J = 7.2 Hz,
Me), 0.82 (3H, t, J = 6.3 Hz, Me); 13C NMR (CDCl3): ¤ 169.0
(C=O), 101.6 (C-5), 78.0 (C-2, CH2), 40.3, 35.9, 29.3, 25.1, 22.4,
19.8 (CH2), 13.8, 13.5 (Me). FAB HRMS (acetone/NBA) m/z:
calcd for C11H22NO3 216.1600 (M + H); found 216.1598.
5-Hydroxy-3-isopropyl-5-methyloxazolidin-4-one (4g): Yield
(40%); Rf = 0.46 (EtOAc:hexane = 9:1 v/v); Colorless liquid; IR
(CHCl3): ¯ 3500-3200 (OH), 1708 (C=O); 1H NMR (CDCl3): ¤
5.05 (1H, d, J = 2.1 Hz, CH2), 4.87 (1H, d, J = 2.1 Hz, CH2), 4.20
(1H, sep, J = 4.2 Hz, CH), 2.29 (1H, br s, OH), 1.52 (3H, s, CH3),
1.16 (6H, d, J = 4.2 Hz, 2Me); 13C NMR (CDCl3): ¤ 168.5 (C=O),
99.9 (C-5), 74.4 (C-2, CH2), 43.2 (CH), 22.9, 20.0, 19.8 (Me). FAB
HRMS (acetone/NBA) m/z: calcd for C7H14NO3 160.0974
(M + H); found 160.0956.
5-Ethyl-5-hydroxy-3-isopropyloxazolidin-4-one (4h): Yield
(45%); Rf = 0.46 (EtOAc:hexane = 9:1 v/v); colorless liquid; IR
(CHCl3): ¯ 3500-3200 (OH), 1707 (C=O); 1H NMR (CDCl3): ¤
5.13 (1H, d, J = 2.1 Hz, CH2), 4.96 (1H, d, J = 2.1 Hz, CH2), 4.32
(1H, sep, J = 4.2 Hz, CH), 3.22 (1H, br s, OH), 2.00-1.85 (2H, m,
CH2), 1.24 (3H, d, J = 4.2 Hz, Me), 1.22 (3H, d, J = 4.2 Hz, Me),
0.94 (3H, t, J = 4.5 Hz, Me); 13C NMR (CDCl3): ¤ 167.5 (C=O),
102.1 (C-5), 75.0 (C-2, CH2), 43.1 (CH), 29.7 (CH2), 20.2, 19.8,
7.4 (Me). FAB HRMS (acetone/NBA/NaI) m/z: calcd for
C8H15NO3Na 196.0950 (M + Na); found 196.0976.
5-Hydroxy-3-isopropyl-5-propyloxazolidin-4-one (4i): Yield
(39%); Rf = 0.50 (EtOAc:hexane = 8:2 v/v); colorless liquid; IR
(CHCl3): ¯ 3585-3100 (OH), 1705 (C=O); 1H NMR (CDCl3): ¤
5.14 (1H, d, J = 2.1 Hz, CH2), 4.94 (1H, d, J = 2.1 Hz, CH2), 4.29
(1H, sep, J = 4.2 Hz, CH), 4.03 (1H, br s, OH), 1.93-1.76 (2H, m,
CH2), 1.48-1.42 (1H, m, CH2), 1.36-1.31 (1H, m, CH2), 1.27 (3H,
d, J = 4.2 Hz, Me), 1.20 (3H, d, J = 4.2 Hz, Me), 0.93 (3H, t,
J = 4.8 Hz, Me); 13C NMR (CDCl3): ¤ 167.8 (C=O), 101.8 (C-5),
74.9 (C-2, CH2), 43.1 (CH), 38.5, 16.5 (CH2), 20.1, 19.7, 13.9
(Me). FAB-HRMS (acetone/NBA/NaI) m/z: calcd for C9H17NO3-
Na 210.1106 (M + Na); found 210.1102.
20 The physical data of the hydroxyoxazolidinones 4b-4i are listed
below.
3-Benzyl-5-ethyl-5-hydroxyoxazolidin-4-one (4b): Yield (60%);
Rf = 0.30 (EtOAc:hexane = 6:4 v/v); pale yellow needle (from
Et2O/hexane); mp 103 °C; IR (KBr): ¯ 3400-3100 (OH), 1678
(C=O); 1H NMR (CDCl3): ¤ 7.33-7.25 (5H, m, arom H), 5.04 (1H,
a
b
a
s, CH2 ), 4.77 (1H, s, CH2 ), 4.68 (1H, d, J = 15.0 Hz, PhCH2 ),
b
4.33 (1H, d, J = 15.0 Hz, PhCH2 ), 3.67 (1H, br s, OH), 1.97 (2H,
m, CH2), 0.94 (3H, t, J = 7.5 Hz, Me); 13C NMR (CDCl3): ¤ 169.0
(C=O), 134.7, 128.9, 128.0, 127.8 (arom C), 101.9 (C-5), 77.7
(C-2, CH2), 44.6 (PhCH2), 29.4 (CH2), 7.5 (Me). FAB HRMS
(acetone/NBA) m/z: calcd for C12H16NO3 222.1130 (M + H);
found 222.1135.
3-Benzyl-5-hydroxy-5-propyloxazolidin-4-one (4c): Yield (60%);
Rf = 0.50 (EtOAc:hexane = 6:4 v/v); pale yellow needle (from
EtOAc/hexane); mp 103 °C; IR (KBr): ¯ 3500-3100 (OH), 1708
(C=O); 1H NMR (CDCl3): ¤ 7.28-7.15 (5H, m, arom H), 4.92 (1H,
d, J = 1.8 Hz, CH2), 4.69 (1H, d, J = 1.8 Hz, CH2), 4.58 (1H, d,
Chem. Lett. 2011, 40, 1349-1351
© 2011 The Chemical Society of Japan
www.csj.jp/journals/chem-lett/