Deprotection of 1,1-diacetates with [NO+·Crown·H(NO3) 2-]

Article abstract of DOI:10.1081/SCC-120006463

An ionic complex has been obtained from N₂O₄ in the presence of the macrocyclic polyether 18-crown-6. This crystalline compound was used as an effective deprotecting agent for the conversion of 1,1-diacetates to their corresponding aldehydes at room temperature with quantitative yields.

Full text of DOI:10.1081/SCC-120006463

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DEPROTECTION OF 1,1-DIACETATES WITH [NO+ ⋅ CROWN
-
⋅ H(NO3)2 ]
Mohammad Ali Zolfigol a , Mohammad Hassan Zebarjadian a , Iraj Mohammadpoor-Baltork b
& Mojtaba Shamsipur c
a Chemistry Department , College of Science , Bu-Ali Sina University , Hamadan, 65174, Iran
b Chemistry Department , College of Science , Isfahan University , Isfahan, I.R. Iran
c Chemistry Department , College of Science , Razi University , Kermanshah, Iran
Published online: 18 Oct 2011.
To cite this article: Mohammad Ali Zolfigol , Mohammad Hassan Zebarjadian , Iraj Mohammadpoor-Baltork & Mojtaba
-
Shamsipur (2002) DEPROTECTION OF 1,1-DIACETATES WITH [NO+ ⋅ CROWN ⋅ H(NO3)2 ], Synthetic Communications:
An International Journal for Rapid Communication of Synthetic Organic Chemistry, 32:18, 2803-2808, DOI: 10.1081/
SCC-120006463
To link to this article: http://dx.doi.org/10.1081/SCC-120006463
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SYNTHETIC COMMUNICATIONS
Vol. 32, No. 18, pp. 2803–2808, 2002
DEPROTECTION OF 1,1-DIACETATES
WITH [NOQ ꢀ Crown ꢀ H(NO3)2
R
]
1,
*
MohammadAli Zolfigol,
1
MohammadHassan Zebarjadian,
Iraj Mohammadpoor-Baltork,2 andMojtaba Shamsipur
3
1Chemistry Department, College of Science, Bu-Ali Sina
University, Hamadan, Zip Code 65174, Iran
2Chemistry Department, College of Science,
Isfahan University, Isfahan, I.R. Iran
3Chemistry Department, College of Science,
Razi University, Kermanshah, Iran
ABSTRACT
An ionic complex has been obtained from N2O4 in the presence
of the macrocyclic polyether 18-crown-6. This crystalline
compound was used as an effective deprotecting agent for the
conversion of 1,1-diacetates to their corresponding aldehydes
at room temperature with quantitative yields.
Selective protection and deprotection of functional groups are of great
importance in the synthesis of polyfunctional organic molecules.
1,1-Diacetates have found considerable attention during recent years owing to
their moderate stability[1] and ease of preparation.[1–10] They are also known
as interesting alternatives to acetals for the protection of aldehydes and can be
*Corresponding author. Fax: (þ98) 811 8272404; E-mail: Zolfi@basu.ac.ir
2803
DOI: 10.1081/SCC-120006463
Copyright & 2002 by Marcel Dekker, Inc.
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com

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2804
ZOLFIGOL ET AL.
used as starting materials for the synthesis of valuable intermediate in Dies–
Alder cycloaddition reactions.[11] Regeneration of the original aldehydes
from their corresponding 1,1-diacetates is a useful transformation in organic
chemistry. The several methods for this purpose have been introduced in the
chemical literature.[1,12–22] In the course of our investigation on the applica-
tion of Lewis acids as effective catalysts to this transformation,[23] we were
interested to find a completely homogeneous reagent for the conversion of
1,1-diacetates to their corresponding aldehydes. In continuation of our
studies on the application of NOX,[24] N2O4,[25] metal nitrate dinitrogen
tetroxide complexes[26] and transition metal complexes with macrocyclic
ethers,[27] we found that 18-crown-6gives an ionic complex with N O4 gas
2
as [NOþ ꢀ Crown ꢀ H(NO3)2ꢁ] in quantitative yields. By using this new
reagent, in this article we now report a simple and convenient method for
the conversion of 1,1-diacetates (1) to their corresponding aldehydes (2)
under mild conditions.
A good range of 1,1-diacetates (1) with different functional groups
were subjected to the deprotection reaction in the presence of
[NOþ ꢀ Crown ꢀ H(NO3)2ꢁ] (I) and dry SiO2 in dichloromethane. The depro-
tection reactions were performed under mild conditions at room tempera-
ture with quantitative yields (Scheme 1). Unlike the substrates 1a–m, the
reagent was not suitable for deprotection of compound 1n, the deprotection
of this compound was sluggish and a mixture of products was produced.
The deprotection reaction can be readily carried out by placing the
complex [NOþ ꢀ Crown ꢀ H(NO3)2ꢁ] (I), 1,1-diacetates (1), dry SiO2 and
CH2Cl2 as the solvent in a reaction vessel and efficient stirring of the result-
ing mixture at room temperature. The reactions were completed after 5 min.
The reaction mixture was filtered and dichloromethane was removed by
simple distillation over a water bath (40–50ꢂC). Highly pure aldehydes (2)
were finally obtained by passing the residue through a pad of silica gel.
In conclusion, practical and efficient deprotection of 1,1-diacetates was
ꢁ
achieved using the present methodology. The [NOþ ꢀ Crown ꢀ H(NO3)2
]
complex, with easy preparation and handling can act as a relatively stable
and efficient reagent for this transformation under mild and homogeneous
conditions. Meanwhile, 18-crown-6can be recycled and reused. We
believe that the present methodology is an important addition to existing
methodologies.
EXPERIMENTAL SECTION
General: Chemicals were purchased from Fluka, Merck, Riedel-
dehaen AG and Aldrich chemical companies. Silica gel of mesh 60–70 was

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DEPROTECTION OF 1,1-DIACETATES
2805
Scheme 1.
used. The deprotection products were characterized by comparison of their
1
spectral (IR, H-NMR, 13C-NMR and TLC) and physical data with the
authentic samples. [NOþ ꢀ Crown ꢀ H(NO3)2ꢁ] was synthesized according
to the reported procedure,[28] subjected to a slight modification. Here, we
used N2O4 gas instead of liquid N2O4. Dinitrogen tetroxide (N2O4) gas
was generated in situ according to our previously reported procedure as
follows:[25,26]
Generation of NO2–N2O4 Gas: Lead(II) nitrate (50 g) was crushed into
a powder and was dried in an oven at 120ꢂC for three days. The resulting
powder was transferred into a one-necked round-bottomed flask (250 mL)
which was equipped with an air condenser and a gas trap containing P2O5.
The flask was heated by a Bunsen burner to generate a brownish-red
NO2–N2O4 gas which was used immediately for the subsequent preparation
of [NOþ ꢀ Crown ꢀ H(NO3)2ꢁ].

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2806
ZOLFIGOL ET AL.
Preparation of [NOþ ꢀ Crown ꢀ H(NO3)2ꢁ]: A solution of 18-crown-6
(5.286g, 0.02 mol) in CH 2Cl2 (10 mL) was prepared in a three-necked
round-bottomed flask (50 mL) equipped with a magnetic stirrer, a gas inlet
tube, a thermometer and a drying tube and cooled to ꢁ10ꢂC with an ice-salt
while being stirred. Generated NO2–N2O4 gas was bubbled through this sol-
ution 30 min. The solvent was evaporated under vacuum at 20ꢂC to give the
[NOþ ꢀ Crown ꢀ H(NO3)2ꢁ] complex as a pale yellow deliquescent solid com-
pound 1 [8.380 g, 0.02 mol (ꢃ100%)], m.p. 50–55ꢂC [Lit[28] m.p. 53–55ꢂC].
1H NMR (FT-90 MHz, CDCl3/TMS): 3.536(s, 24H), 11.464 (s, 1H).
General Procedure for Deprotection of 1,1-Diacetates: A solution of
1,1-Diacetates (1, 1 mmol), [NOþ ꢀ Crown ꢀ H(NO3)2ꢁ] (0523 g, 1.25 mmol)
and dry SiO2 (0.4 g) in dichloromethane (5 mL) was vigorously stirred mag-
netically at room temperature. The progress of reaction was followed by
TLC. The reaction was completed after 5 min. The reaction mixture was
filtered. The residue was washed with CH2Cl2 (2 ꢄ 5 mL). Dichloromethane
was removed by a water bath (40–50ꢂC) and simple distillation. The residue
was passed through a pad of silica gel [eluent: acetone/petroleum ether
(10 : 90)]. The solvent was evaporated and the highly pure aldehydes (2)
were obtained quantitatively. For recycling 18-crown-6, the pad of silica gel
was washed with acetone. Evaporation of acetone gave pure 18-crown-6.
ACKNOWLEDGMENT
The financial support for this work by the research affairs of Bu-Ali
Sina University, Hamadan, Iran is acknowledged.
REFERENCES
1. Kochhar, K.S.; Bal, B.S.; Deshpande, R.P.; Rajadhyasha, S.N.; Pinnick,
H.W. J. Org. Chem. 1983, 48, 1765.
2. Freeman, F.; Karchefski, E.M. J. Chem. Eng. Data 1977, 25, 355.
3. Michie, J.K.; Miller, J.A. Synthesis 1981, 824.
4. Olah, G.A.; Mehrota, A.K. Synthesis 1982, 962.
5. Pereira, C.; Gigante, B.; Marcelo-Curto, M.J.; Carreyre, H.; Perot, G.;
Guisnet, M. Synthesis 1995, 1077.
6. Kumar, P.; Hegde, V.R.; Kumar, T.P. Tetrahedron Lett. 1995, 36, 601.
7. Zhang, Z.-H.; Li, T.-S.; Fu, C.-G. J. Chem. Research(S) 1997, 174.
8. Jin, T.-S.; Du, G.-Y.; Zhang, Z.-H.; Li, T.-S. Synth. Commun. 1997,
27, 2261.

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DEPROTECTION OF 1,1-DIACETATES
2807
9. Bandgar, B.P.; Mahajan, N.P.; Mulay, D.P.; Thote, J.L.; Wadgoankar,
P.P. J. Chem. Research(S) 1995, 470.
10. Deka, N.; Kalta, D.J.; Borah, R.; Sarma, G.C. J. Org. Chem. 1997,
62, 1563.
11. Sinder, B.B.; Amin, S.G. Synth. Commun. 1978, 8, 117.
12. Lieberman, S.V.; Connor, R. Org. Synth. Coll. 1951, 2, 441.
13. Tsag, S.M.; Wood, E.H.; Johnson, J.R. Org. Synth. Coll. 1955, 3, 641.
14. Narayana, C.; Padmanabhan, S.; Kabalka, G.W. Tetrahedron Lett.
1990, 31, 6977.
15. Cotella, P.; Catteau, J.-P.; Tetrahedron Lett. 1992, 33, 3855.
16. Varma, R.S.; Chatterjee, A.K.; Varma, M. Tetrahedron Lett. 1993,
34, 3207.
17. Ku, Y.-Y.; Patel, R.; Sawick, D. Tetrahedron Lett. 1993, 34, 8037.
18. Li, T.-S.; Zhang, Z.-H.; Fu, C.-G. Tetrahedron Lett. 1997, 38, 3285.
19. Jin, T.-S.; Ma, Y.-R.; Zhang, Z.-H.; Li, T.-S. Synth. Commun. 1997,
27, 3379.
20. Villemin, D.; Martin, B. J. Chem. Research(S) 1994, 146.
21. Perez, E.R.; Marrero, A.L.; Perez, R.; Autie, M.A. Tetrahedron Lett.
1995, 36, 1779.
22. Aggarwal, V.K.; Fonquerna, S.; Vernnall, G.P. Synlett 1998, 849.
23. (a) Mohammadpoor-Baltork, I.; Aliyan, H. J. Chem. Research(S)
1999, 272; (b) Mohammadpoor-Baltork, I.; Aliyan, H. Indian J.
Chem. 1999, 38B, 1223; (c) Mohammadpoor-Baltork, I.; Aliyan, H.
Synth. Commun. 1999, 29, 2741.
24. (a) Zolfigol, M.A.; Kiany-Borazjani, M.; Sadeghi, M.M.;
Mohammadpoor-Baltork, I.; Memarian, H.R. Synth. Commun. 2000,
30, 551; (b) Zolfigol, M.A.; Kiany-Borazjani, M.; Sadeghi, M.M.;
Memarian, H.R.; Mohammadpoor-Baltork, I. Synth. Commun. 2000,
30, 2945; (c) Zolfigol, M.A.; Kiany-Borazjani, M.; Sadeghi, M.M.;
Memarian, H.R.; Mohammadpoor-Baltork, I. J. Chem. Research(S)
2000, 197; (d) Zolfigol, M.A.; Nematollahi, D.; Mallakpour, S.E.
Synth. Commun. 1999, 29, 2277; (e) Zolfigol, M.A.; Mallakpour, S.E.
Synth. Commun. 1999, 29, 4061; (f) Zolfigol, M.A. Synth. Commun.
2000, 30, 1593; (g) Zolfigol, M.A.; Kiany-Borazjani, M.; Mallakpour,
S.E.; Nassr-Isfahani, H. Synth. Commun. 2000, 30, 2573; (h) Zolfigol,
M.A.; Madrakian, E.; Ghaemi, E. Indian. J. Chem. 2000, 39B, 308;
(i) Zolfigol, M.A.; Ghaemi, E.; Madrakian, E. Synth. Commun. 2000,
30, 1689; (j) Zolfigol, M.A.; Kiany-Borazjani, M.; Sadeghi, M.M.;
Mohammadpoor-Baltork, I.; Memarian, H.R. Synth. Commun. 2000,
30, 3919; (k) Zolfigol, M.A.; Ghorbani Choghamarani, A.; Shirini, F.A.;
Keypour, H.; Salehzadeh, S. Synth. Commun. 2001, 31, 359; (l) Zolfigol,
M.A. Synth. Commun. 1999, 29, 905; (m) Zolfigol, M.A.; Ghaemi, E.;

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2808
ZOLFIGOL ET AL.
Madrakian, E.; Kiany-Borazjani, M. Synth. Commun. 2000, 30, 2057;
(n) Zolfigol, M.A.; Shirini, F.; Ghorbani Choghamarani, A.; Taqian-
nasab, A.; Keypour, H.; Salehzadeh, S. J. Chem. Research(S) 2000, 420.
25. (a) Mallakpour, S.E.; Zolfigol, M.A. J. Sci. I. R. Iran 1993, 4, 199;
(b) Mallakpour, S.E.; Zolfigol, M.A. Indian J. Chem. 1995, 34B, 183;
(c) Mallakpour, S.E.; Zolfigol, M.A. Indian J. Chem. 1995, 34B, 302.
(d) Mallakpour, S.E.; Zolfigol, M.A. Indian J. Chem. 1998, 37B, 1001;
(e) Mallakpour, S.E.; Zolfigol, M.A. Indian J. Chem. 1999, 38B, 777.
26. (a) Zolfigol, M.A.; Iranpoor, N.; Firouzabadi, H. Orient. J. Chem.
1998, 14, 369; (b) Firouzabadi, H.; Iranpoor, N.; Zolfigol, M. A.
Synth. Commun. 1997, 27, 3301; (c) Iranpoor, N.; Firouzabadi, H.;
Zolfigol, M.A. Synth. Commun. 1998, 28, 2773; (d) Firouzabadi, H.;
Iranpoor, N.; Zolfigol, M.A. Synth. Commun. 1998, 28, 377;
(e) Iranpoor, N.; Firouzabadi, H.; Zolfigol, M.A. Synth. Commun.
1998, 28, 367; (f) Firouzabadi, H.; Iranpoor, N.; Zolfigol, M.A. Bull.
Chem. Soc. Jpn. 1998, 71, 2169; (g) Iranpoor, N.; Firouzabadi, H.;
Zolfigol, M.A. Bull. Chem. Soc. Jpn. 1998, 71, 905.
27. Shamsipur, M. Research Letter, 13th Iranian Chemistry and Chemical
Ingineering Congress.
28. Ricard, S.; Audet, P.; Savoie, R. J. Mol. Struct. 1988, 178, 135.
Received in the UK July 26, 2001