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Pyridine catalyzed reaction of tetracyanoethylene and activated 1,3-dicarbonyl CH-acid compounds: A rapid and efficient synthesis of pyran annulated heterocyclic systems

Pyridine catalyzed reaction of tetracyanoethylene and activated 1,3-dicarbonyl CH-acid compounds: A rapid and efficient synthesis of pyran annulated heterocyclic systems

Available online at www.sciencedirect.com Catalysis Communications 9 (2008) 1082–1086 www.elsevier.com/locate/catcom Pyridine catalyzed reaction of ...

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Available online at www.sciencedirect.com

Catalysis Communications 9 (2008) 1082–1086 www.elsevier.com/locate/catcom

Pyridine catalyzed reaction of tetracyanoethylene and activated 1,3-dicarbonyl CH-acid compounds: A rapid and efficient synthesis of pyran annulated heterocyclic systems Ahmad Shaabani *, Ali Hossein Rezayan, Afshin Sarvary, Abbas Rahmati, Hamid Reza Khavasi Department of Chemistry, Shahid Beheshti University, P.O. Box 19396-4716, Tehran, Iran Received 31 July 2007; received in revised form 2 October 2007; accepted 16 October 2007 Available online 22 October 2007

Abstract A pyridine catalyzed reaction between tetracyanoethylene and various activated CH-acid compounds to afford the corresponding pyran annulated heterocyclic ring systems in high yield at room temperature within a few minutes, is described. The work-up procedure is very simple and the products do not require further purification.  2007 Elsevier B.V. All rights reserved. Keywords: Pyridine catalyzed reaction; Tetracyanoethylene; CH-acid; Pyrans

1. Introduction Pyrans and their derivatives are of considerable interest because of their wide range of biological property [1], such as spasmolytic, diuretic, anti-coagulant, anti-cancer, antianaphylactic activity [2–6]. In addition, they can be used as cognitive enhancers, for the treatment of neurodegenerative disease, including Alzheimer’s disease, amyotrophic lateral sclerosis, Huntington’s disease, Parkinson’s disease, AIDS associated dementia and Down’s syndrome as well as for the treatment of schizophrenia and myoclonus [7]. 4H-Pyrans also constitute the structural unit of a series of natural products [8,9]. Tetracyanoethylene (TCNE) is the simplest of the percyanoalkenes (cyanocarbons). Due to four powerful electron-withdrawing cyano groups the C–C double bond is highly electron-deficient and it is strongly electrophilic reagent. TCNE undergoes two principal types of reaction, namely, addition to its double bond and replacement of a *

Corresponding author. Fax: +98 21 22431663. E-mail address: [email protected] (A. Shaabani).

1566-7367/$ - see front matter  2007 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2007.10.012

cyano group. TCNE has received an extensive amount of study and the chemistry of this compound has been reviewed several times [10–12]. However a literature survey revealed that the reaction of TCNE with pyridine in the presence of activated CH-acid has not been investigated. In view of our general interest in multi-component reactions (MCRs) involving zwitterionic species [13], we were intrigued by the possibility of trapping of the 1,3-zwitterionic intermediate generated from pyridine 1 and tetracyanoethylene (TCNE) 2 with activated CH-acids 3. In the event we did not observe the expected MCR product 5; instead the reaction afforded the corresponding pyran annulated heterocyclic systems (PAHS) 4 with pyridine playing as a catalyst in the reaction between the TCNE and activated CH-acids (Scheme 1). 2. Results and discussion In an initial experiment, the reaction of TCNE 1 with 5,5-dimethylcyclohexane-1,3-dione (dimedone) 2 in the presence of pyridine (10 mole%) in CH2Cl2 afforded the

A. Shaabani et al. / Catalysis Communications 9 (2008) 1082–1086

CN

NC

1083 O

NC 5-25 min 90-96 %

Z

O NC

CN

+ N

+ NC

1

H Z H

CN

O

CH2Cl2 r.t.

Z

O 3

2

O 4a-g

H2N

CN

N

CN

H CN

O 5

CN Product Z Time (min) Yield (%)

4a

4b

H2C CH2 C CH2CH2 H3C CH3 15 90

5 92

4c

4d

4e

CH2CH2CH2

CH3-NCON-CH3

H3C

4g

4f O

15

20

10

94

96

94

NCH3

O 10

25

93

90

Scheme 1.

2-amino-5,6,7,8-tetrahydro-7,7-dimethyl-5-oxochromene3,4,4- tricarbonitrile 4a in 90% yield. Similar reactivity was observed with other cyclic1,3-dicarbonyl compounds such as cyclopentane-1,3-dione and cyclohexane-1,3-dione and results are summarized in Table 1. All of the products are new compounds that were characterized by IR, 1H NMR, 13C NMR spectra and elemental analyses data. The mass spectra of these compounds displayed molecular ion peaks at the appropriate m/z values [14]. The 1H NMR spectrum of 4a exhibited three singlets identified as methyl (at d = 1.04 ppm) and two methylenes (at d = 2.44 and 2.59 ppm) protons. The NH2 protons resonance at d = 8.40 ppm. The 1H decoupled 13C NMR spectrum of 4a showed 12 distinct resonances in agreement with the suggested structures. Finally, the structure of 4f was confirmed unambiguously by single crystal X-ray analysis (Fig. 1) [15]. As can be seen from the packing diagram of 4f, Fig. 2, there is some N–H. . .O [H4C. . .O2 = 2.430(2), N4. . .O2 = ˚ and N4–H4C. . .O2 = 140.7(1), symmetry code: 3.15(1) A x, y, z] and N–. . .N [H4B. . .N3i = 2.127(2), N4. . .N3i = 2.990(1) AA and N4–H4B. . .N3i = 169.2(2) and ii H4C. . .N2 = 2.756(2), N4. . .N2ii = 3.325(2) AA and N4H4C. . .N2ii = 124.1(2), symmetry codes: (i) x, y, z and (ii) x + 1, y, z], that it seems to be an effective factor in the stabilization of the crystal structure. These intermolecular hydrogen bonds link the molecules into two-dimensional networks. In view of the success of the above reactions, we explored the use of 1,3-dimethylpyrimidine-2,4,6(1H,3H, 5H)-trione, 4-hydroxy-6-methyl-2H-pyran-2-one, 4hydroxy-2H-chromen-2-one and 4-hydroxy-1-methylquinolin-2(1H)-one as activated CH-acid in this reaction. Treatment of 1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-tri-

one, 4-hydroxy-6-methyl-2H-pyran-2-one, 4-hydroxy-2Hchromen-2-one or 4-hydroxy-1-methylquinolin-2(1H)-one with TCNE 1 in the presence of pyridine in CH2Cl2 at Table 1 Reaction of TCNE with dimedone or 4-hydroxychromenon in the presence of various catalysts Entry 1

CH-acid

Catalyst

O

Yield (%)/Time (min) 90/15

O

N

2

O

85/15

O

N

3

O

82/35

O

N

4

5

O

O

PPh3

85/15

93/10

OH

N O

O

(continued on next page)

1084

A. Shaabani et al. / Catalysis Communications 9 (2008) 1082–1086

Table 1 (continued) Entry 6

CH-acid

Catalyst

Yield (%)/Time (min)

N4

85/15

OH

N3 C14 C15

N O

7

O3

O

C13 C5

88/30

OH

C7 C4

C10

C6

N

N1 C8

O

C12

O C3

8

PPh3

OH

N2 C9

C1

85/20 C2

O1

O

9

10

O

Na2CO3

50/120

NaOH

40/120

O

OH

O2

Fig. 1. ORTEP representation of 4f.

O

OH

O

C11

O

room temperature led to the formation the corresponding pyran annulated heterocyclic systems in high yields (Table 1, Entries 4–7).

To illustrate the role of pyridine, the reaction of TCNE 1 and dimedone 2 was studied in the absence of pyridine. The yield of product was only traces of desired product under similar conditions after 15 min. As indicated in Table 1, using triphenylphosphine, quinoline and isoquinoline to replace pyridine under the same conditions afforded similar results, however the reaction yield is lower than pyridine. It may be explained the basicity of the triphenylphosphine, quinoline and isoquinoline is weaker than pyridine. We checked the reaction of TCNE and 4-hydroxychromenon in the presence of bases such as Na2CO3 and NaOH. As indicated in Table 1 (entries 9 and 10), we obtained the desired product, however, reaction yield was considerably decreased.

Fig. 2. (a) Crystal packing diagram and (b) two-dimensional view of 4f. Hydrogen bonds are shown as dashed lines.

A. Shaabani et al. / Catalysis Communications 9 (2008) 1082–1086

The above mentioned results are showed the pyridine acts not only as a nucleophile but base, which the nucleophilicity of it prefer to its basicity. Two reasonable possibilities are indicated in Scheme 2. (i) Proposed mechanism based on nucleophilicity of pyridine: The first step of this mechanism involves the nucleophilic addition of pyridine to the electron-deficient TCNE and subsequent protonation of the high reactive 1:1 adduct by dimedone leads to the salt 7 followed by attack of the anion part of dimedone on the cation part of salt 7 to form the product 4 (Mechanism a). (ii) Proposed mechanism based on basicity of pyridine: Since the reaction works in the presence of bases such as Na2CO3 and NaOH, thus we suggest pyridine acts as a base and attack to the CH-acid to abstract one hydrogen (Mechanism b).

a CN O

NC NC H2N

5

3 4 2 1 O

8

N

NH O

H

6 7

CN CN H CN

CN CN NC 9 O

4a

8 O

CN N

C H

O

N 1

CN

O

O

H CN CN

1085

3. Experimental 3.1. Techniques and materials Melting points were measured on an Electrothermal 9100 apparatus and are uncorrected. Mass spectra were recorded on a FINNIGAN-MAT 8430 mass spectrometer operating at an ionization potential of 70 eV. IR spectra were recorded on a Shimadzu IR-470 spectrometer. 1H and 13C NMR spectra were recorded on a BRUKER DRX-300 AVANCE spectrometer at 300.13 and 75.47 MHz. NMR spectra were obtained on solutions in DMSO-d6 using TMS as internal standard. The chemicals used in this work were purchased from Merck and Fluka Chemical Company. 4. Conclusions In conclusion, we have introduced a rapid and very efficient triphenylphosphine, quinoline, isoquinoline or pyridine-catalyzed approach for the synthesis of pyran annulated heterocyclic ring systems under mild reaction conditions with excellent yields. The present method has the advantages that not only are the reaction performed under neutral conditions, but the substances can be mixed without any modification. The work-up procedure is very simple and the products do not require further purification. The simplicity of the present procedure makes it an interesting alternative to other approaches [16]. Work along this line is currently in progress. Acknowledgement

7 NC

CN

H

H

O

O NC

2

CN

CN

CN

CN

CN

We gratefully acknowledge the financial support from the Research Council and the Catalysis Center of Excellence (CCE) of Shahid Beheshti University.

N 6

References

3

b O

O 3

NC CN O NC H2N

N H

N 1

6

NC

2

CN

O

N C

O

CN O CN CN 7

N C

CN CN O CN

Scheme 2.

N H

4a

NH C CN CN CN H O 8 O

CN

NC

O

O

OO

O

[1] G.R. Green, J.M. Evans, A.K. Vong, in: A.R. Katritzky, C.W. Rees, E.F.V. Scriven (Eds.), Comprehensive Heterocyclic Chem. II, vol. 5, Pergamon Press, Oxford, 1995, p. 469. [2] W.O. Foye, Prinicipi di Chemico Farmaceutica, Piccin, Padova, Italy, 1991, p. 416. [3] L.L. Andreani, E. Lapi, Bull. Chim. Farm. 99 (1960) 583. [4] Y.L. Zhang, B.Z. Chen, K.Q. Zheng, M.L. Xu, X.H. Lei, Yao Xue Xue Bao 17 (1982) 17; Y.L. Zhang, B.Z. Chen, K.Q. Zheng, M.L. Xu, X.H. Lei, Chem. Abstr. 96 (1982) 135383e. [5] L. Bonsignore, G. Loy, D. Secci, A. Calignano, Eur. J. Med. Chem. 28 (1993) 517. [6] E.C. Witte, P. Neubert, A. Roesch, Ger. Offen DE (1986) 3427985; E.C. Witte, P. Neubert, A. Roesch, Chem. Abstr. 104 (1986) 224915f. [7] C.S. Konkoy, D.B. Fick, S.X. Cai, N.C. Lan, J.F.W. Keana, PCT Int. Appl. WO (2000) 0075123; C.S. Konkoy, D.B. Fick, S.X. Cai, N.C. Lan, J.F.W. Keana, Chem. Abstr. 134 (2001) 29313a. [8] S. Hatakeyama, N. Ochi, H. Numata, S. Takano, J. Chem. Soc., Chem. Commun. (1988) 1202. [9] J.A. Ciller, N. Martin, C. Seoane, J. Soto, J. Chem. Soc., Perkin Trans.1 (1985) 2581. [10] A.J. Fatiadi, Synthesis (1987) 749.

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A. Shaabani et al. / Catalysis Communications 9 (2008) 1082–1086

[11] A.J. Fatiadi, Synthesis (1987) 959. [12] D.N. Dhar, Chem. Rev. 67 (1967) 611. [13] (a) A. Shaabani, E. Soleimani, H.R. Khavasi, R.D. Hoffmann, U.C. Rodewaldb, R. Pottgen, Tetrahedron Lett. 47 (2006) 5493; (b) A. Shaabani, M.B. Teimouri, S. Arab-Ameri, Tetrahedron Lett. 45 (2004) 8409; (c) A. Shaabani, M.B. Teimouri, H.R. Bijanzadeh, Tetrahedron Lett. 43 (2002) 9151. [14] Typical experimental procedure: Preparation of 2-amino-5,6,7,8tetrahydro-7,7-dimethyl-5-oxochromene-3,4,4- tricarbonitrile (4a) To a magnetically stirred solution of tetracyanoethylene (0.128 g, 1.0 mmol) and 5,5-dimethylcyclohexane-1,3-dione (0.140 g, 1.0 mmol) in CH2Cl2 (15 mL) was added, drop wise, a mixture of pyridine (0.008 g, 10 mol%) in CH2Cl2 (2 mL) at room temperature and was stirred for 15 min. After completion of the reaction, solvent was removed under vacuum and the residue was crystallized from CH2Cl2/n-hexane 1:2 to yield 0.241 g of 4a as a pink powder (90%). mp 198–200 C. IR (KBr) (mmax, cm 1): 3370, 3345 (NH2), 2209 (CN), 1681 ([email protected]). 1H NMR (300 MHz, DMSO-d6): dH (ppm) 1.04 (6H, s, 2CH3), 2.44 (2H, s, CH2), 2.59 (2H, s, CH2), 8.40 (2H, s, NH2). 13C NMR (75 MHz, DMSO-d6): dC (ppm) 13.76, 18.58, 27.18, 30.07, 31.77, 49.69, 101.91, 113.74 (CN), 116.16 (CN), 158.83, 166.36, 193.94 ([email protected]). MS, m/z (%): 268 (M+, 20), 242 (40), 226 (100), 185 (55), 157 (30), 129 (35), 83 (45), 57 (50), 41 (60). Anal. Calcd for C14H12N4O2: C, 62.68; H, 4.51; N, 20.88. Found: C, 62.55; H, 4.43; N, 20.69. 2Amino-6,7-dihydro-5-oxocyclopenta[b]pyran-3,4,4(5H)-tricarbonitrile (4b) Cream powder (0.208 g, 92%): mp 178–180 C. IR (KBr) (mmax, cm 1): 3382, 3360 (NH2), 2201 (CN), 1666 ([email protected]). 1H NMR (300 MHz, DMSO-d6): dH (ppm) 2.61 (2H, broad s, CH2), 2.84 (2H, broad s, CH2), 8.60 (2H, s, NH2). 13C NMR (75 MHz, DMSOd6) dc = 19.06, 29.43, 33.69, 49.26, 105.46, 113.09 (CN), 116.68 (CN), 161.08, 180, 198.85 ([email protected]). MS, m/z (%): 226 (M+, 30), 200 (25), 184 (20), 78 (20), 57 (60), 41(100). Anal. Calcd for C11H6N4O2: C, 58.41; H, 2.67; N, 24.77. Found: C, 58.28; H, 2.58; N, 23.91. 2-Amino5,6,7,8-tetrahydro-5-oxochromene-3,4,4-tricarbonitrile (4c) Pink powder (0.225 g, 94%): mp 196–198 C. IR (KBr) (mmax, cm 1): 3372, 3355 (NH2), 2208 (CN), 1668 (C=O). 1H NMR (300 MHz, DMSO-d6): dH(ppm) 1.99 (2H, broad s, CH2), 2.49 (2H, broad s, CH2), 2.64 (2H, broad s, CH2), 8.36 (2H, s, NH2). 13C NMR (75 MHz, DMSO-d6): dC (ppm) 19.53, 27.40, 30.71, 35.92, 50.29, 103.10, 114.37 (CN), 116.67 (CN), 159.13, 168.83, 194.58 ([email protected]). MS, m/z (%): 240 (M+, 25), 214 (100), 184 (90), 158 (40), 120 (35), 88 (30), 66 (65), 39 (85). Anal. Calcd for C12H8N4O2: C, 60.00; H, 3.36; N, 23.32. Found: C, 60.12; H, 3.33; N, 23.11. 6-Amino-1,2,3,4-tetrahydro-1,3-dimethyl-2,4-dioxopyrano[3,2- d]pyrimidine-7,8,8-tricarbonitrile (4d) Light green powder (0.272 g, 96%): 210 C (dec). IR (KBr) (mmax, cm 1): 3351, 3340 (NH2), 2214 (CN), 1718 ([email protected]), 1685 ([email protected]). 1H NMR (300 MHz, DMSO-d6): dH (ppm) 3.23 (3H, s, CH3), 3.29 (3H, s, CH3),8.67 (2H, s, NH2). 13C NMR (75 MHz, DMSO-d6) dC (ppm) 28.48, 30.02, 32.08, 50.28, 78.75, 114.07 (CN), 116.23 (CN), 149.72, 152.94, 158.81 (C=O), 159.62 (C=O). MS, m/z (%): 268 (M+16, 20), 242 (25), 209 (30), 181 (20), 154 (70), 132 (25), 105 (60), 78 (60), 56 (100), 41 (75). Anal. Calcd for C12H8N6O3: C, 50.71; H, 2.84;

N, 29.57. Found: C, 50.13; H, 2.76; N, 29.34. 2-Amino-7-methyl-5oxopyrano[4,3-b]pyran-3,4,4(5H)-tricarbonitrile (4e) Cream powder (0.238 g, 94%): 203 C (dec). IR (KBr) (mmax, cm 1): 3382, 3366 (NH2), 2215 (CN), 1729 ([email protected]). 1H NMR (300 MHz, DMSO-d6): dH (ppm) 2.33 (3H, s, CH3), 6.48 (1H, s, olefin), 8.52 (2H, s, NH2). 13C NMR (75 MHz, DMSO-d6) dC (ppm) 20.06, 31.70, 49.77, 89.38, 98.94, 113.53 (CN), 116.63 (CN), 159.30, 160.15, 160.68, 167.72 ([email protected]). MS, m/z (%): 228 (M+-26, 20), 200 (25), 85 (95), 69 (30), 43 (100). Anal. Calcd for C12H6N4O3: C, 56.70; H, 2.38; N, 22.04. Found: C, 56.36; H, 2.23; N, 21.87. 2-Amino-5-oxopyrano[3,2c]chromene-3,4,4(5H)-tricarbonitrile (4f) White powder (0.248 g, 93%): 220 C (dec). IR (KBr) (mmax, cm 1): 3355, 3345 (NH2), 2213 (CN), 1712 ([email protected]). 1H NMR (300 MHz, DMSO-d6): dH (ppm) 7.60– 7.87 (4H, m, arom), 8.69 (2H, s, NH2). 13C NMR (75 MHz, DMSOd6) dC (ppm) 32.19, 50.03, 92.49, 112.57 (CN), 113.48 (CN), 116.52, 117.55, 123.78, 125.86, 135.71, 153.14, 156.43, 158.69, 159.10 ([email protected]). MS, m/z (%): 264 (M+-26, 35), 236 (20), 150 (40), 121 (100), 92 (35), 65 (20), 45 (20). Anal. Calcd for C15H6N4O3: C, 62.07; H, 2.08; N, 19.3. Found: C, 61.34; H, 2.10; N, 19.04. 2-Amino-5,6-dihydro-6methyl-5-oxopyrano[3,2-c]quinoline-3,4,4- tricarbonitrile (4g) White powder (0.273 g, 90%): 219 C (dec). IR (KBr) (mmax, cm 1): 3375, 3360 (NH2), 2203 (CN), 1676 ([email protected]). 1H NMR (300 MHz, DMSOd6): dH (ppm) 3.69 (3H, s, CH3), 7.45–7.96 (4H, m, arom), 8.53 (2H, s, NH2). 13C NMR (75 MHz, DMSO-d6) dC (ppm) 30.22, 32.57, 50.34, 96.56, 112.09 (CN), 114.27 (CN), 116.07, 116.95, 123.46, 123.55, 134.40, 140.00, 152.20, 158.59, 159.52 ([email protected]). MS, m/z (%): 304 (MH+, 10), 285 (50), 276 (100), 249 (40), 150 (30), 104 (30), 84 (25), 49 (70). Anal. Calcd for C16H9N5O2: C, 63.37; H, 2.99; N, 23.09. Found: C, 62.10; H, 2.88; N, 22.05. [15] Crystal data analyses: Stoe IPDSII two-circle diffractometer, MoKa radiation (k = 0.71073); T = 120(2) K; Graphite monochromator; numerical absorption correction. Structure solution by direct methods using SHELXS and refinement by full-matrix least-squares on F2 using SHELXL of the X-STEP32 suite of programs [17] all nonhydrogen atoms were refined anisotropically. Crystal data for 4f:C15H6N4O3, M = 290.24 g mol 1; crystal dimensions 0.40 · 0.30 · 0.18 mm3; monoclinic, space group P21/c; ˚ , b = 97.981(7), a = 8.6361(8), b = 13.492(9), c = 10.6419(9) A ˚ 3; Z = 4; F(0 0 0) = 592, qcalc = 1.570 g cm 3; V = 1227.97(6) A 2.38 < h < 29.25; section of the reciprocal lattice: 10 6 h 6 11, 17 6 k 6 18, 14 6 l 6 14; of 9121 measured reflections, 3286 were independent and 3286 with I > 2r(I); absorption coefficient 0.115 mm 1; R1 = 0.0400 for I > 2r(I) and wR2 = 0.1004 (all data); ˚ 3) and hole ( 0.224 e A ˚ 3). (CCDC No. largest peak (0.386 e A 661917). [16] (a) S. Abdolmohammadi, S. Balalaie, Tetrahedron Lett. 48 (2007) 3299; (b) D. Heber, E. Stoyanov, Synthesis (2003) 227; (c) C. Wiener, C.H. Schroeder, B.D. West, K.P. Link, J. Org. Chem. (1962) 3086; (d) F. Bossert, H. Meyer, E. Wehinger, Angew. Chem. 93 (1981) 755. [17] Stoe and Cie, X-STEP32, Version 1.07b: Crystallographic package, Stoe and Cie GmbH, Darmatadt, Germany, 2000.