Unsymmetrical dienones
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 9, September, 2005
2225
2ꢀBenzylidenecyclopentanone (2). A mixture of cyclopentaꢀ
none (8.4 g, 0.1 mol) and benzaldehyde (5.3 g, 0.05 mol) was
added to a solution of NaOH (2.5 g) in water (100 mL) and
stirred at room temperature for 1 h. The solution was neutralꢀ
ized with HCl, the resulting oily layer was separated, and the
product from the aqueous layer was extracted with ether. The
ethereal extracts were combined with the oil and dried over
K2CO3. The combined extract was concentrated and the residue
was distilled in vacuo and recrystallized. The yield of compound
2 was 2.89 g (34%), m.p. 68—69 °C (from heptane) (cf. Ref. 5:
m.p. 69—70 °C). 1H NMR (CDCl3), δ: 2.02 (quint, 2 H,
C(4)—CH2—, J = 7.2 Hz); 2.40 (t, 2 H, C(5)—CH2—, J =
7.8 Hz); 2.97 (td, 2 H, C(3)—CH2—, J = 7.0 Hz, J = 2.7 Hz);
7.34—7.44 (m, 4 H, mꢀHPh, pꢀHPh, =CH—Ph); 7.53 (d, 2 H,
oꢀHPh, J = 7.3 Hz).
Synthesis of compounds 1a—d by condensation of 2ꢀbenzylꢀ
idenecyclopentanone with heteroaromatic aldehydes (general
procedure). A solution of 2ꢀbenzylidenecyclopentanone (2)
(1 mmol) and the corresponding aldehyde (1 mmol) in 95%
EtOH (10 mL) was stirred in the presence of aqueous 10% KOH
(0.5 mL) for 30—40 min. The completion of the reaction was
determined by TLC. The precipitate that formed was filtered off
and recrystallized from EtOH.
(E,E)ꢀ5ꢀBenzylideneꢀ2ꢀ(4ꢀpyridylmethylene)cyclopentanone
(1a). The yield was 0.04 g (13%), m.p. 192 °C (from EtOH).
Found (%): C, 82.99; H, 5.73; N, 5.22. C18H15NO. Calcuꢀ
lated (%): C, 82.76; H, 5.75; N, 5.36. IR, ν/cm–1: 1675 (C=O).
1H NMR (CDCl3), δ: 3.17 (br.s, 4 H, CH2); 7.38—7.51 (m,
6 H, =CH—py, mꢀHPh, pꢀHPh, βꢀHpy); 7.58—7.68 (m, 3 H,
oꢀHPh, =CH—Ph); 8.69 (d, 2 H, αꢀHpy, J = 4.5 Hz).
(E,E)ꢀ5ꢀBenzylideneꢀ2ꢀ(3ꢀpyridylmethylene)cyclopentanone
(1b). The yield was 0.16 g (53%), m.p. 198 °C (from EtOH).
Found (%): C, 82.97; H, 5.74; N, 5.63. C18H15NO. Calcuꢀ
lated (%): C, 82.76; H, 5.75; N, 5.36. IR, ν/cm–1: 1675 (C=O).
1H NMR (CDCl3), δ: 3.15 (br.s, 4 H, CH2); 7.34—7.52 (m,
(E,E)ꢀ5ꢀBenzylideneꢀ2ꢀ(2ꢀthenylidene)cyclopentanone (1d).
The yield was 0.26 g (84%), m.p. 188 °C (from EtOH) (cf.
Ref. 3: m.p. 188—189 °C). Found (%): C, 76.80; H, 5.24.
C17H14OS. Calculated (%): C, 76.69; H, 5.26. IR, ν/cm–1: 1675
(C=O). 1H NMR (CDCl3), δ: 3.03, 3.16 (both m, 2 H each,
CH2); 7.18 (dd, 1 H, βꢀHthienyl, J = 3.7 Hz, J = 5.1 Hz);
7.35—7.48 (m, 4 H, mꢀHPh, pꢀHPh, β´ꢀHthienyl); 7.55—7.63
(m, 4 H, =CH—Ph, oꢀHPh, αꢀHthienyl); 7.84 (br.s, 1 H,
=CH—C4H3S).
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 03ꢀ03ꢀ32401)
and the Russian Academy of Sciences (Program of the
Chemistry and Materials Sciences Division "Theoretical
and Experimental Investigation of the Nature of Chemiꢀ
cal Bonding and the Mechanisms of the Most Important
Chemical Reactions and Processes", Grant No. 047).
References
1. C. Janiak, J. Chem. Soc., Dalton Trans., 2003, 2871.
2. S. Z. Vatsadze, M. A. Kovalkina, N. V. Sviridenkova, N. V.
Zyk, A. V. Churakov, L. G. Kuz´mina, and J. A. K. Howard,
Crystal Eng. Commun., 2004, 6, 112.
3. S. V. Tsukerman, L. A. Kutulya, and V. F. Lavrushin,
Zh. Obshch. Khim., 1964, 34, 3597 [J. Gen. Chem. USSR,
1964, 34 (Engl. Transl.)].
4. H. Vieweg and G. Wagner, Pharmazie, 1979, 34, 785.
5. A. P. Phillips and J. Mentha, J. Am. Chem. Soc., 1956,
78, 140.
6. D. N. Kevill, E. D. Weiler, and N. H. Cromwell, J. Org.
Chem., 1964, 29, 1276.
7. A. Hassner and T. C. Mead, Tetrahedron, 1964, 20, 2201.
8. M. Moraru and F. Chiraleu, Rev. Roum. Chim., 1972,
17, 1235.
9. T. Lorand, D. Szabo, A. Foldesi, and A. Neszmelyi, Acta
Chim. Acad. Sci. Hung., 1982, 110, 231.
10. N. V. Averina, G. S. Borisova, A. A. Semioshkin, K. A.
Potekhin, E. V. Kudryavtseva, Yu. T. Struchkov, and N. S.
Zefirov, Dokl. Akad. Nauk, 1995, 345, 624 [Dokl. Chem.,
1995, 345 (Engl. Transl.)].
4 H, mꢀHPh, pꢀHPh, =CH—py); 7.53—7.72 (m, 4 H, oꢀHPh
,
=CH—Ph, βꢀHpy); 7.88 (d, 1 H, γꢀHpy, J = 8.0 Hz); 8.60 (m,
1 H, αꢀHpy); 8.85 (br.s, 1 H, α´ꢀHpy).
(E,E)ꢀ5ꢀBenzylideneꢀ2ꢀ(2ꢀpyridylmethylene)cyclopentanone
(1c). The yield was 0.1 g (33%), m.p. 162 °C (from EtOH).
Found (%): C, 82.58; H, 5.67; N, 5.35. C18H15NO. Calcuꢀ
lated (%): C, 82.76; H, 5.75; N, 5.36. IR, ν/cm–1: 1680 (C=O).
1H NMR (CDCl3), δ: 3.15, 3.39 (both m, 2 H each, CH2);
11. A. George and H. J. Roth, Tetrahedron Lett., 1971, 4057.
7.18—7.24 (m, 1 H, βꢀHpy); 7.34—7.56 (m, 5 H, mꢀHPh, pꢀHPh
,
β´ꢀHpy, =CH—py); 7.58—7.67 (m, 3 H, oꢀHPh, =CH—Ph);
7.72 (td, 1 H, γꢀHpy, J = 7.8 Hz, J = 2.0 Hz); 8.73 (d, 1 H,
αꢀHpy, J = 4.0 Hz).
Received December 17, 2004;
in revised form July 19, 2005