A New Reaction of N-substituted Formamides with Trichloroethylene under Conditions of Phase-Transfer Catalysis (PTC)

Abstract

Reaction of N-aryl formamides 1 with trichloroethylene (TRI) carried out in the presence of 50% aq sodium hydroxide and a catalyst, tetra-butylammonium hydrogen sulfate (TBAHS), affords substituted enamidines 2, and pyrrole-2,5-diylidenediamines 3, in good yields. Formation of these products is rationalized.

phase-transfer catalysis - formamides - trichloroethylene

References

1 Hopf H. Witulski B. Modern Acetylene Chemistry   Stang PJ. Diederich F. VCH; Weinheim: 1995.  p.48 

2a Dehmlow EV. Dehmlow SS. Phase Transfer Catalysis   3rd ed.:  Verlag Chemie; Weinheim: 1993. 

2b Starks CM. Liotta CL. Halpern M. Phase-transfer Catalysis   Chapman and Hall; New York London: 1994. 

2c Mkosza M. FedoryÒski M. In Handbook of Phase Transfer Catalysis   Sasson Y. Neumann R. Blackie Academic and Professional; London: 1997.  p.135 

3a JoÒczyk A. Gierczak AH. Synthesis  1998,  962 

3b JoÒ czyk A. Gierczak AH. Tetrahedron  2000,  56:  6083 

4 Pielichowski J. Bogda D. Polish J. Chem.  1988,  40:  483 

5a Pielichowski J. Bogda D. Liebigs Ann. Chem.  1988,  595 

5b Pielichowski J. Bogda D. Bull. Acad. Pol. Sci., Chim.  1989,  37:  123 ; Chem. Abstr. 1990, 112, 198222

6 Martynov AV. Mirskova AN. Kalikhman ID. Voronkov MG. Zh. Org. Khim.  1988,  24:  509 ; Chem. Abstr. 1989, 110, 153824

7

JoÒczyk, A.; Michalski, K., manuscript in preparation.

8 Pielichowski J. Popielarz R. Tetrahedron  1984,  40:  2671 

9

Experimental Procedure: Amide 1a (0.73 g, 6 mmol), diethyl ether (15 mL), cyclohexane (5 mL), TRI (1.58 g, ca 1.1 mL, 12 mmol) and TBAHS (0.02 g, 0.06 mmol) were vigorously stirred while 50% aq NaOH (4.8 g, 3.2 mL, 60 mmol) was added dropwise at 20-25 °C. After addition, the reaction was carried out for 15 min, the mixture was poured into the ice with water, the phases were separated, the water phase was extracted with CH₂Cl₂ (5 × 20 mL), the combined organic extracts were dried (MgSO₄) and concentrated. The products 2a and 3a were isolated by column chromatography [Merck silica gel 60 (230-400 mesh), eluent CH₂Cl₂]. 2a: ¹H NMR (400 MHz, CDCl₃): δ = 3.98
(2 H, s), 6.36 (1 H, s), 6.91-7.49 (10 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 33.7, 115.2, 120.9, 123.5, 127.6, 128.0, 129.0, 129.4, 133.3, 139.4, 148.2, 152.2. Anal. Calcd for C₁₆H₁₃Cl₃N₂: C, 56.58; H, 3.86; N, 8.25; Cl 31.31. Found: 56.63; H, 3.79; 8.26; 31.23. 3a: ¹H NMR (400 MHz, CDCl₃): δ = 6.81 (2 H, s), 6.91-7.62 (15 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 122.1, 124.0, 125.4, 127.3, 128.4, 128.8, 134.5, 149.0, 157.2. Anal. Calcd for C₂₂H₁₇N₃: C, 81.71; H, 5.36; N, 12.99. Found: C, 81.58; H, 5.36; N, 13.06.
Spectral data for 2 and 3. 2b: ¹H NMR (400 MHz, CDCl₃): δ = 2.33 (3 H, s), 2.40 (3 H, s), 3.98 (2 H, s), 6.33 (1 H, s), 6.73-7.40 (8 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 21.4, 33.8, 114.9, 117.9, 121.6, 124.3, 124.7, 128.1, 128.7, 128.8, 129.1, 133.4, 138.8, 139.3, 139.4, 148.3, 152.1. Anal. Calcd for C₁₈H₁₇Cl₃N₂: C, 58.80; H, 4.66; N, 7.62; Cl 28.93. Found: C, 58.72; H, 4.58; N, 7.73; Cl, 28.86. 3b: ¹H NMR (400 MHz, CDCl₃): δ = 2.37 (6 H, s), 2.45 (3 H, s), 5.29 (2 H, s), 6.79-7.41 (12 H, m); ¹³C NMR (100 MHz, CDCl₃):
δ = 21.3, 21.5, 119.0, 122.8, 124.6, 125.3, 125.6, 128.3, 128.5, 129.1, 134.4, 138.5, 149.1, 157.2. Anal. Calcd for C₂₅H₂₃N₃: C, 82.16; H, 6.34; N, 11.50. Found: C, 82.10; H, 6.39; N, 11.45. 2c: ¹H NMR (400 MHz, CDCl₃): δ = 2.32 (3 H, s), 2.39 (3 H, s), 3.95 (2 H, s), 6.34 (1 H, s), 6.83-7.35 (8 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 20.8, 21.2, 33.6, 114.7, 120.8, 127.6, 129.4, 130.0, 132.8, 133.4, 136.7, 138.0, 145.8, 152.3. Anal. Calcd for C₁₈H₁₇Cl₃N₂: C, 58.80; H, 4.66; N, 7.62; Cl 28.93. Found: C, 58.54; H, 4.70; N, 7.68; Cl, 29.00. 3c: ¹H NMR (400 MHz, CDCl₃): δ = 2.34 (6 H, s), 2.39 (3 H, s), 5.29 (2 H, s), 6.82-7.47 (12 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 20.8, 21.2, 121.7, 122.0, 125.1, 128.2, 129.3, 129.5, 126.6, 131.9, 133.3, 137.1, 146.7, 157.3. Anal. Calcd for C₂₅H₂₃N₃: C, 82.16; H, 6.34; N, 11.50. Found: C, 82.14; H, 6.38; N, 11.60. 2d: ¹H NMR (400 MHz, CDCl₃): δ = 3.95 (2 H, s), 6.38 (1 H, s), 6.82-7.43 (8 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 33.5, 115.9, 122.2, 128.8, 129.1, 129.7, 132.7, 133.9, 137.7, 146.5, 152.5. Anal. Calcd for C₁₆H₁₁Cl₅N₂: C, 47.04; H, 2.71; N, 6.86; Cl 43.39. Found: C, 47.08; H, 2.80; N, 6.92; Cl, 43.34. 3d: ¹H NMR (400 MHz, CDCl₃): δ = 5.30 (2 H, s), 6.82-7.48 (12 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 122.5, 122.7, 125.2, 126.3, 128.3, 128.8, 138.0, 146.4, 153.5. Anal. Calcd for C₂₂H₁₄Cl₃N₃: C, 61.92; H, 3.31; N, 9.85; Cl, 24.92. Found: C, 61.83; H, 3.28; N, 9.74; Cl, 24.80. 2e: ¹H NMR (400 MHz, CDCl₃): δ = 3.77 (3 H, s), 3.80 (3 H, s), 3.92 (2 H, s), 6.87 (1 H, s), 6.93-7.42 (8 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 33.3, 55.2, 55.3, 114.0, 114.4, 121.9, 129.3, 131.6, 133.4, 141.5, 152.5, 155.8, 159.1. Anal. Calcd for C₁₈H₁₇Cl₃N₂O₂: C, 54.09; H, 4.29; N, 7.01; Cl 26.61. Found: C, 53.97; H, 4.20; N, 7.10; Cl, 26.53. 3e: ¹H NMR (400 MHz, CDCl₃): δ = 3.78 (9 H, s), 3.81 (2 H, s), 6.83-7.48 (12 H, m); ¹³C NMR (100 MHz, CDCl₃): δ = 55.2, 55.3, 65.7, 113.9, 114.1, 123.1, 124.9, 127.3, 129.6, 142.5, 156.4, 157.4, 158.4. Anal. Calcd for C₂₅H₂₃N₃O₃: C, 72.62; H, 5.61; N, 10.16. Found: C, 72.74; H, 5.50; N, 10.24.

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Crystallographic data for the structures 2a and 3a have been deposited with the Cambridge Crystallographic Data Center and allocated the deposition numbers CCDC 188398 and CCDC 188399, respectively. Copies of the data can be obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, (UK) [fax:[phone] or e-mail: [e-mail]].

11

Structurally related amidines have already been synthesized via reaction of N-substituted amides with POCl₃ [12] or PCl₅. [12b] [13]

12a Fukuda M. Okamoto Y. Sakurai H. Bull. Chem. Soc. Jpn.  1977,  50:  1895 

12b Prajznar B. Rocz. Chem.  1962,  36:  1449 ; Chem. Abstr. 1963, 59, 5139.

13a Von Braun J. Jostes F. Heymons A. Chem. Ber.  1927,  60:  92 

13b Yamagida S. Fujita T. Ohoka M. Katagiri I. Miyabe M. Komori S. Bull. Chem. Soc. Jpn.  1973,  46:  303 

13c Meth-Cohn O. Westwood KT. J. Chem. Soc., Perkin Trans. 1  1983,  2089 

14 Only a few structures, related to azacyclic products 3, are described: Anwar M. Abdel-Hay FI. Fahmy M. Rev. Roum. Chim.  1978,  23:  1085 ; Chem. Abstr. 1979, 90, 54899b

15 Speziale AJ. Smith LR. J. Am. Chem. Soc.  1962,  84:  1868 

16 Aniline reacted with TRI at ca 120 °C affording mixture of products: Shklyar SA. Vestsi Nats. Akad. Navuk Belarusi, Ser. Khim. Navuk  1972,  95 ; Chem. Abstr. 1973, 78, 15678

17 Pielichowski J. Czub P. Bull. Soc. Chim. Belg.  1995,  104:  407