Facile one-pot method for the synthesis of novel N-dichloroacetyl-1,3- oxazolidines

Article abstract of DOI:10.1080/00397910802585860

A short and efficient route to synthesis and structural characterization of a series of novel N-dichloroacetyl-5-ethyl-1,3-oxazolidine derivatives has been developed. These new compounds, characterized by the substitution at position 2 by alkyls, cycloalkanes, benzyls, or aryls, have been synthesized in good yields via a sequential procedure involving cycloaddition, condensation, and acylation. All the compounds are characterized by infrared, ¹H NMR, and ¹³C NMR.

Full text of DOI:10.1080/00397910802585860

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Facile One-Pot Method for
the Synthesis of Novel N-
Dichloroacetyl-1,3-oxazolidines
Ying Fu a b , Honggang Fu a c , Fei Ye b , Jingdong
Mao d & Xiaotian Wen b
a Department of Applied Chemistry , Harbin Institute
of Technology , Harbin, Heilongjiang, China
b College of Science, Northeast Agricultural
University , Harbin, Heilongjiang, China
c School of Chemistry and Materials Science ,
Heilongjiang University , Harbin, Heilongjiang, China
d Department of Chemistry and Biochemistry , Old
Dominion University , Norfolk, Virginia, USA
Published online: 16 Jun 2009.
To cite this article: Ying Fu , Honggang Fu , Fei Ye , Jingdong Mao & Xiaotian Wen
(2009) Facile One-Pot Method for the Synthesis of Novel N-Dichloroacetyl-1,3-
oxazolidines, Synthetic Communications: An International Journal for Rapid
Communication of Synthetic Organic Chemistry, 39:14, 2454-2463, DOI:
10.1080/00397910802585860
To link to this article: http://dx.doi.org/10.1080/00397910802585860
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Synthetic Communications1, 39: 2454–2463, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802585860
Facile One-Pot Method for the Synthesis of
Novel N-Dichloroacetyl-1,3-oxazolidines
Ying Fu,1,2 Honggang Fu,1,3 Fei Ye,2 Jingdong Mao,4
and Xiaotian Wen2
1Department of Applied Chemistry, Harbin Institute of Technology,
Harbin, Heilongjiang, China
2College of Science, Northeast Agricultural University, Harbin,
Heilongjiang, China
3School of Chemistry and Materials Science, Heilongjiang University,
Harbin, Heilongjiang, China
4Department of Chemistry and Biochemistry, Old Dominion University,
Norfolk, Virginia, USA
Abstract: A short and efficient route to synthesis and structural characterization
of a series of novel N-dichloroacetyl-5-ethyl-1,3-oxazolidine derivatives has been
developed. These new compounds, characterized by the substitution at position 2
by alkyls, cycloalkanes, benzyls, or aryls, have been synthesized in good yields via
a sequential procedure involving cycloaddition, condensation, and acylation. All
1
the compounds are characterized by infrared, H NMR, and 13C NMR.
Keywords: Acylation, condensation, cycloaddition, dichloroacetyl oxazolidines,
synthesis
Substituted oxazolidines are important synthetic targets because of their
biological activity, pharmacological activity, and extensive use as chiral
auxiliaries for synthesis of many chiral compounds.[1–6] In addition, the
discovery of N-dichloroacetyl oxazolidine as an herbicide safener has
drawn widespread attention in agricultural biochemistry. Some new
Received July 18, 2008.
Address correspondence to Honggang Fu, Department of Applied Chemistry,
Harbin Institute of Technology, Harbin, 150001, China. E-mail: fuying@neau.
edu.cn
2454

Synthesis of N-Dichloroacetyl-1,3-oxazolidines
2455
methods for the synthesis of oxazolidine derivatives have been described
and are generally classified into two main approaches in the literature.[7,8]
The first path, more frequently used, was based on the reduction of
amino acids with NaBH4=I2 or LiAlH4 to yield the desired amino alco-
hols, followed by the condensation of b-amino alcohol with aldehydes
˚
or ketones in the presence of 4 A molecular sieves with dichloromethane
as solvent, resulting in the complete formation of the corresponding
oxazolidines.[9] The second approach consists of a three-atom plus a
two-atom ring closure in which the carbonyl group provided the two
atoms.[10] The acylation of oxazolidines and dichloroacetyl chloride was
achieved by using triethylamine as the catalyst and benzene as the reac-
tion medium.[11,12] The literature revealed that there are few synthetic
routes to 2-substituted oxazolidines characteristic of alkyls, cycloalkanes,
benzyls, and aryls, with the facile one-pot conversion from epoxide with
aldehydes or ketones without separating the intermediate and using any
catalyst. In our study, we found that the condensation could be carried
out without any catalyst and that also it was not necessary to separate
the intermediate products. In the acylation, the factors influencing the
yield were acid attaching agent, reaction temperature, solvent, and struc-
tures of aldehydes or ketones.
In the present study, to synthesize a novel series of N-dichloroacetyl
oxazolidines with high bioactivity, we developed a new, one-pot,
three-step synthetic strategy. In this approach, we prepared these com-
pounds through cycloaddition of epoxide with ammonia to produce
b-amino alcohol; then a condensation reaction with aldehydes or ketones
to form 1,3-oxazolidine; and finally acylation by dichloroacetyl chloride
with sodium hydroxide rather than triethylamine as the acid attaching
agent. The present procedure required only simple manipulations and
inexpensive reagents; thus, it should be appropriate for providing the deri-
vatives in great demand. A series of new N-dichloroacetyl-5-ethyl-1,3-
oxazolidine derivatives reported here were characterized by alkyl,
cycloalkane, and phenyl at position 2 of the oxazolidine (Table 1).
1,2-Epoxybutyane, a commercially available, cheap starting material,
was treated with ammonia water in alkaline solution at 33–35ꢀC for
1.5 h. 1-Amino-2-butanol was obtained in a good yield (74.8%).[13] Oxazo-
lidine ligands 2a–f were prepared with 1-amino-2-butanol and aldehyde or
ketone by heating at reflux for 2 h in solvent without any catalyst. Then
the reaction system was cooled, and dichloroacetyl chloride was added
with sodium hydroxide as the acid attaching agent to produce the
N-dichloroacetyl oxazolidines in good yields (Scheme 1).
We improved the synthetic route by using a different acid attaching
agent and reaction temperature. The possible process for the reaction is
depicted in Scheme 2. The reaction of aldehyde or ketone with b-amino

2456
Y. Fu et al.
Table 1. Formation of N-dichloroacetyl oxazolidines from aldehydes or ketones
and amino alcohol
Aldehyde or
Ketone
Temp Time Yield
(h)
Entry
1
Product
Solvent (ꢀC)
(%)
CH2Cl2 3–8
1
69.1
2
CH2Cl2 3–8
1
50.2
3
4
CH2Cl2 3–8
2
3
54.5
32.5
CH2Cl2 ꢁ5–0
5
C6H6
ꢁ5–0
2
47.8
6
C6H6
3–8
3
41.2
alcohol yielded an open-chain imine, which existed in equilibrium with
oxazolidine.[14] Because oxazolidine can easily become an imine under
alkaline conditions,[15] we choose sodium hydroxide solution rather than

Synthesis of N-Dichloroacetyl-1,3-oxazolidines
2457
Scheme 1. Route for the synthesis of N-dichloroacetyl oxazolidines.
triethylamine as the acid attaching agent. Triethylamine is soluble in the
organic layer and renders the organic phase where oxazolidine is present
strongly alkaline. Under the alkaline condition, oxazolidine quickly
became the imine, and the desired products cannot be attained or are
hard to isolate (Table 2). In contrast, sodium hydroxide is insoluble in
the organic phase, and it not only keeps the organic phase weakly alka-
line but also reacts quickly with by-product HCl. The resulting NaCl can
be easily removed from the organic phase.
By comparing the structures of the substituents at position 2 with the
yields, we find that the more complex the structures of the substituents,
the less the yields of the desired products. We suspect that the substitu-
ents at position 2 increase the steric effect and render acylation difficult
(Fig. 1). Consequently, the yields of compounds 3d–f are less than those
of compounds 3a–c. In addition, the p–p conjugation effect of benzalde-
hyde makes it difficult to react with amino alcohol and thus decreases the
yield of 3e.
Another factor controlling the yield is the temperature. Under the
alkaline condition and as temperature greater than 18ꢀC, oxazolidine
Scheme 2. Equilibrium between imine and oxazolidines.

2458
Y. Fu et al.
Table 2. Comparison of two catalysts for the formation of
3a and 3c
Yield (%)
Compound
(Et)3N
NaOH (aq.)
3a
3c
35.2
20.1
69.1
40.5
easily decomposes to the imine. Furthermore, the reaction of oxazolidine
with dichloroacetyl chloride is exothermic. Logically we should employ a
low reaction temperature. However, a suboptimal temperature will
prolong the time required to add dichloroacetyl chloride and result in
superfluous by-products. In the present study, the reaction temperature
was optimized at 3–8ꢀC, although for 3d and 3e the best reaction
temperature is À5 to 0ꢀC. Because benzaldehyde and cyclopentanone
are unstable in atmosphere and easy to be oxidated at room temperature,
their yields were increased at À5 to 0ꢀC.
Stirring time also influences the yields. If the structure of ketone is
complex, the yield can be increased by using a long stirring time
(3d and 3f), except for 3e (Table 1). In the presence of sodium hydroxide
Figure 1. Molecular structure of 3a.

Synthesis of N-Dichloroacetyl-1,3-oxazolidines
2459
solution, the Cannizzaro reaction takes place; the benzaldehyde changes
to benzoic acid and benzyl alcohol, making the equilibrium (Scheme 2)
back to the reactant.
Finally, in the present study, the single crystal of 3a was obtained by
dissolving it in the solvent of ethyl acetate and light petroleum, followed
by slow evaporation. The colorless crystal with a dimension of
0.22 mm ꢂ 0.18 mm ꢂ 0.12 mm was selected for x-ray diffraction analysis.
The bond lengths and bone angles of the oxazolidine ring were both nor-
mal, with the bond lengths of C5–N2 and C5–O3 close to the typical C–N
and C–O bond lengths, respectively (Fig. 1). The C6–O2 bond length of
˚
˚
1.215(3) A was indicative of a double bond C¼O (1.21–1.23 A). The p–p
conjunction between N2 and C6–O2 resulted in shorter bond length of
˚
˚
C6–N2 [1.333(4) A] than the typical C–N bond length (1.472 A) (Fig. 1).
In conclusion, we have developed a novel, efficient, one-pot synthesis
of N-dichloroacetyl-1,3-oxazolidine derivatives via cycloaddition, con-
densation, and acylation. We obtained the single crystal structure for
3a for the first time. The advantages of our approach are mild reaction
conditions, short reaction time, easy workup, and good yields of products.
EXPERIMENTAL
The infrared (IR) spectra were taken on a KJ-IN-27 G IR spectrophot-
ometer (KBr). The 1H NMR spectra and 13C NMR spectra were
recorded on a Bruker Avance 300-MHz nuclear magnetic resonance
(NMR) spectrometer with CDCl3 as the solvent and tetramethylsilane
as the internal standard. The melting points were determined on a Beijng
Taike melting-point apparatus (X-4) and are uncorrected.
Typical Procedure for the Preparation of Compounds 3a–f
1-Amino-2-butanol (0.034 mol) and 0.034 mol of the aldehyde or ketone
were mixed with 20 mL of benzene. The reaction mixture was stirred at
33–35ꢀC for 1 h. Then, the mixture was heated to reflux, water was
stripped off, the mixture was cooled to 0ꢀC, and 4.2 mL of 33% sodium
hydroxide solution were added. Afterward, 4.0 mL (0.041 mol) of
dichloroacetyl chloride were added dropwise with stirring and cooling
in an ice bath. Stirring continued for 1 h. The organic phase was rinsed
with water until pH 7. The organic layer was dried over anhydrous mag-
nesium sulfate, and the solvent was removed under vacuum. Compounds
3b and 3d–3f were separated on silica gel by column chromatography.
The crude products 3a and 3c were recrystallized with ethyl acetate and
light petroleum until white crystals were obtained.

2460
Y. Fu et al.
Spectral and Crystal Data for New Compounds
N-Dichloroacetyl-2,2-dimethyl-5-ethyl-1,3-oxazolidine (3a)
White crystal, mp 97–98 C. IR(KBr, v=cmꢁ1): 3049–2872 (C-H), 1670
ꢀ
~
1
(C¼O), 1414 (Cl2HC-CO); H NMR (CDCl3, 300 MHz, d ppm): 6.04
(s, 1H, Cl2CH-), 3.91–4.10 (m, 2H, -N-CH2-C), 3.27–3.34 (t, 1H,
-C-CH-O-), 1.66 (s, 6H, CH3-C-CH3), 1.56–1.59 (m, 2H, C-CH2-C),
0.97–1.02 (t, 3H, -C-CH3); 13C NMR (CDCl3, 300 MHz, d ppm):
159.634, 96.372, 75.926, 66.938, 50.526, 25.758, 25.479, 23.144, 9.730.
Crystal data of compound 3a: C9H15Cl2NO2, monoclinic, space
˚
˚
˚
group P2(1)=c, a ¼ 6.288(5) A, b ¼ 10.736(8) A, c ¼ 17.842(13) A,
3
ꢀ
ꢀ
ꢀ
˚
a ¼ 90 , b ¼ 93.632(12) , c ¼ 90 , V ¼ 1202.1(16) A , Z ¼ 16, Dc ¼
1.734 g cmꢁ3, m ¼ 0.988 mmꢁ1, F(000) ¼ 624. Independent reflections were
obtained in the range of 2.97ꢀ < h < 28.29ꢀ, 2955. The final least-square
cycle gave R1 ¼ 0.0593, xR2 ¼ 0.1609 for 1846 reflections with I > 2r(I).
). The maximum and minimum differences of peak and hole are 0.510
3
˚
and ꢁ0.287 e=A , respectively. Crystal data of the compound 3a was
measured on a Brukcr AXS CCD area-detector diffractometer using gra-
phite monochromated Mo Ka radiation (k ¼ 0.071073 nm) at 273(2) K.
The structure was solved by direct methods using the SHELXS-97 pro-
gram. All the nonhydrogen atoms were refined anisotropically by the
full-matrix least square method on F2. Crystallographic data (excluding
structure factors) for the structure in this article have been deposited with
the Cambridge Crystallographic Data Centre as supplementary publica-
tion number CCDC 686705. Copies of the data can be obtained, free of
charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK [fax: þ44(1223)336033 or e-mail: dposit@ccdc.cam.ac.uc]. Each
request should be accompanied by the complete citation of this article.
N-Dichloroacetyl-2-propyl-5-ethyl-1,3-oxazolidine (3b)
Oil, IR (KBr, v=cmꢁ1): 3151–2876 (C-H), 1670 (C¼O), 1420 (Cl2HC-CO);
~
1H NMR (CDCl3, 300 MHz, d ppm): 6.05 (s, 1H, Cl2CH-), 5.42–5.46 (m,
1H, H-C), 4.04–4.28 (m, 2H, -N-CH2-C), 3.53–3.58 (t, 1H, -C-CH-O-),
1.61–1.81 (m, 4H, C-CH2-CH2-C), 1.39–1.44 (m, 2H, C-CH2-C), 0.93–1.03
(m, 6H, -C-CH3, -C-CH3); 13C NMR (CDCl3, 300 MHz, d ppm): 160.580,
90.603, 78.866, 66.572, 50.456, 34.625, 25.892, 17.648, 13.917, 9.762.
N-Dichloroacetyl-2,2,5-triethyl-1,3-oxazolidine (3c)
White crystal, mp 53–54ꢀC. IR (KBr, ~v=cmꢁ1): 3000–2852 (C-H), 1670
1
(C¼O), 1434 (Cl2HC-CO); H NMR (CDCl3, 300 MHz, d ppm): 6.09

Synthesis of N-Dichloroacetyl-1,3-oxazolidines
2461
(s, 1H, Cl2CH-), 3.97–4.15 (m, 2H, -N-CH2-C), 3.23–3.29 (m, 1H,
-C-CH-O-), 2.20–2.26 (m, 2H, -C-CH2-C), 1.95–2.04 (m, 2H, C-CH2-C),
1.71–1.78 (m, 2H, C-CH2-C), 0.99–1.01 (t, 3H, -C-CH3), 0.88–0.91 (t,
3H, -C-CH3), 0.77–0.78 (t, 3H, -C-CH3); 13C NMR (CDCl3, 300 MHz,
d ppm): 159.525, 101.469, 71.994, 67.031, 51.714, 29.019, 27.951, 26.130,
9715, 8.293, 7.034.
N-Dichloroacetyl-2-ethyl-1-oxa-4-aza-spiro-4,4-noncane (3d)
White crystal, mp 78–79 C. IR (KBr, v=cmꢁ1): 3074–2869 (C-H), 1680
ꢀ
~
1
(C¼O), 1440 (Cl2HC-CO); H NMR (CDCl3, 300 MHz, d ppm): 6.04
(s, 1H, Cl2CH-), 3.84–3.96 (m, 2H, -N-CH2-C), 3.23–3.29 (t, 1H, -C-CH-
O-), 2.15–2.51 (m, 2H, C-CH2-C), 1.63–1.90 [m, 8H, -(CH2)4] 0.98–1.00
(t, 3H, -C-CH3); 13C NMR (CDCl3, 300 MHz, d ppm): 159.533,
105.859, 76.345, 66.851, 50.493, 35.661, 34.921, 25.384, 25.247, 9.752.
N-Dichloroacetyl-2-phenyl-5-ethyl-1,3-oxazolidine (3e)
Oil, IR (KBr, v=cmꢁ1): 3980–2860(C-H), 1685 (C¼O), 1400 (Cl2HC-CO);
~
1H NMR (CDCl3, 300 MHz, d ppm): 7.26–7.45 (m, 5H, C6H5-), 6.46 (s,
1H, Cl2CH-), 6.12 (s, 1H, C-H), 3.98–4.25 (m, 2H, -N-CH2-C), 3.71–3.74
(m, 1H, -C-CH-O-), 1.69–1.79 (m, 2H, C-CH2-C), 0.98–1.00 (t, 3H,
-C-CH3); 13C NMR (CDCl3, 300 MHz, d ppm): 150.980, 137.701,
129.284, 129.039, 128.914, 126.475, 126.237, 89.672, 78.464, 66.469,
49.472, 25.840, 9.728.
N-Dichloroacetyl-2-methyl-2-phenylethyl-5-ethyl-1,3-oxazolidine (3f)
White crystal, mp 72–73 C. IR (KBr, v=cmꢁ1): 3110–2850 (C-H), 1710
ꢀ
~
(C ¼ O), 1415 (Cl2HC-CO); 1H NMR (CDCl3, 300 MHz, d ppm):
7.17–7.26 (m, 5H, C6H5-), 6.05 (s, 1H, Cl2CH-), 3.96–4.16 (m, 2H,
-N-CH2-C), 3.25–3.31 (m, 1H, -C-CH-O-), 2.66–2.70 (t, 2H, C-CH2-C),
2.08–2.43 (m, 2H, C-CH2-C), 1.74–1.77 (m, 2H, C-CH2-C), 1.58 (s, 3H,
-C-CH3), 1.01–1.06 (t, 3H, -C-CH3); 13C NMR (CDCl3, 300 MHz, d
ppm): 159.610, 141.610, 128.517, 128.392, 128.340, 125.894, 125.810,
97.986, 75.747, 66.923, 51.346, 38.613, 29.407, 25.500, 22.691, 9.728.
ACKNOWLEDGMENTS
We are grateful for the support from the Natural Science Foundation of
Heilongjiang Province (No. B200602), the Research Science Foundation

2462
Y. Fu et al.
in Technology Innovation of Harbin (Nos. 2006RFXXN005 and
2007RFQXN017), the Science and Technology Research Project of
Heilongjiang Education Department (No. 11521038), and the Northeast
Agricultural University Doctor Foundation Project. J. D. M. thanks the
Materials Research Science and Engineering Center (MRSEC) at the
University of Massachusetts for NMR machine time.
REFERENCES
1. Agami, C.; Couty, F. The use of N-boc-1,3-oxazolidines as chiral auxiliaries
in asymmetric synthesis. Eur. J. Org. Chem. 2004, 4, 677–685.
2. Iwata, A.; Tang, H.; Kunai, A.; Ohshita, J.; Yamamoto, Y.; Matui, C.
Ring-opening reactions of cyclic acetals and 1,3-oxazolidines with halosilane
equivalents. J. Org. Chem. 2002, 67 (15), 5170–5175.
3. Agami, C.; Comesse, S.; Kadouri-Puchot, C. Asymmetric syntheses of new
functionalized b-amino alcohols via diastereoselective addition of organome-
tallic reagents onto oxazolidines. J. Org. Chem. 2002, 67 (5), 1496–1500.
4. Adam, W.; Schambony, S. B. Diastereoselective epoxidation of oxazolidine-
substituted alkenes by dimethyldioxirane and m-chloroperbenzoic acid:
Facial control through hydrogen bonding by the urea functionality. Org.
Lett. 2001, 3 (1), 79–82.
5. Blanchet, J.; Micouin, B. L.; Husson, H.-P. Synthesis of enantiomerically
pure a-substituted propargylic amines by reaction of organoaluminum
reagents with oxazolidines. J. Org. Chem. 2000, 65, 6423–6426.
6. Matola, T.; Jablonkai, I. Safening efficacy of halogenated acetals, ketals, and
amides and relationship between the structure and effect on glutathione and
glutathione S-transferases in maize. Crop Protection. 2007, 26 (3), 278–284.
7. Katarzyna, B.; Dorota, S.; Tadeusz, G. A concise synthesis of protected
diethyl 1-amino-2-hydroxyalkylphosphonates. Tetrahedron Lett. 2003, 44
(25), 4747–4750.
8. Guirado, A.; Andreu, R.; Galvez, J. Direct conversion of 4-amino-2-phenyl-
2-oxazolines into either 2-arylimino-1,3-oxazolidine or 2-arylimino-1,3-
thiazolidine hydrochlorides. Tetrahedron Lett. 2003, 44 (19), 3809–3821.
9. Kirsten, S.; Frank, G. Efficient oxidative synthesis of 2-oxazolines. Synthesis
2006, 18, 2996–3002.
10. Katritzky, A. R.; Feng, D.; Qi, M. The synthesis of 3,5-di- and 3,5,5-
trisubstituted-1,3-oxazolidines from primary amines and carbonyl
compounds. Tetrahedron Lett. 1998, 39 (38), 6835–6836.
11. Taylor, W. G.; Schreck, C. E. Synthesis and mosquito repellent properties of
some 2-alkyl-N-acetyloxazolidines. Pestic. Sci. 1991, 33 (1), 1–9.
12. Wesley, G. T.; Tse, W. H.; Carl, E. S. Synthesis and mosquito repellent
properties of 2,2-dialkyl- and -2-alkyl-4,4-dimethyl-N-acetyloxazolidines.
Pestic. Sci. 1996, 46 (4), 307–314.
13. Jiying, C.; Qinfen, H.; Wensheng, C.; Fengze, L. Preparation of 2-hydro-
xyethylamine and 2-hydroxypropylmine. Pharm. Ind. 1987, 18 (11), 14–16.

Synthesis of N-Dichloroacetyl-1,3-oxazolidines
2463
14. Nandkishor, N. K.; Girdharilal, B. T.; Sumit, V. G. Efficient oxidative
conversion of aldehydes to 2-substituted oxazolines and oxazines using
(diacetoxyiodo)benzene. Synlett 2007, 12, 1921–1924.
15. Manas, K. G.; Koena, G. Lewis acid mediated nucleophilic ring opening
followed by cycloaddition of 2-aryl-N-tosylaziridines with carbonyl
compounds: Further support towards an SN2-type mechanism. Tetrahedron
Lett. 2007, 48 (18), 3191–3195.