130.9, 131.0, 138.3, 142.6 (Ph, C6H4), 169.5 and 174.1 (C-2,
C-4); m/z 329 (Mϩ, 9%), 238 (33), 174 (95), 173 (25), 172 (22),
119 (43), 118 (51), 116 (41), 104 (100), 91 (92), 77 (31), 71 (76),
65 (27), 44 (23); νmax(KBr)/cmϪ1 1597, 1520.
br s, CH᎐N); δ 14.0 (SMe), 21.7 (Me), 77.4 (PhC), 126.6,
᎐
C
127.0, 127.7, 128.5, 129.2, 129.4, 129.8, 138.3, 139.1, 143.4 (Ph,
1
C H ), 160.1 (CH᎐N, JCH = 183 Hz); m/z 317 (Mϩ ϩ 1, 30%),
᎐
6
4
155 (64), 104 (24), 91 (100), 65 (26); νmax(KBr)/cmϪ1 1615
(C᎐N), 3285 (NH).
᎐
4-Dimethylamino-2-phenyl-1-(p-tolylsulfonyl)-1,3-diazapenta-
1,3-diene 6b. Mp 125–126 ЊC (from light petroleum) (Found:
C, 63.16; H, 6.24; N, 11.93. C18H21N3O2S requires C, 62.95; H,
6.16; N, 12.23%); δH 2.05 and 2.39 (6H, 2s, 2Me), 3.04 and 3.11
(6H, 2s, NMe2), 7.22–7.93 (9H, m, Ph, C6H4); δC 19.6 (Me), 21.0
(Me), 38.1 (NMe2), 126.5, 127.8, 128.5, 128.8, 131.8, 135.7,
139.9, 141.6 (Ph, C6H4), 158.6 and 166.9 (C-4, C-2); m/z 344
(Mϩ ϩ 1, 3%), 188 (96), 176 (30), 173 (34), 155 (21), 104 (57),
91 (100), 65 (25), 56 (22), 44 (43); νmax(KBr)/cmϪ1 1614, 1583.
N-(p-Tolylsulfonyl)methylthiobenzimidate 15
Mp 111 ЊC (from light petroleum) (Found: C, 58.72; H, 4.89;
S, 20.52. C15H15NO2S2 requires C, 58.99; H, 4.95; N, 4.59; O,
10.48; S, 20.99%); δH 2.39 (6H, s, MeC6H4, SMe), 7.21–7.78
(9H, m, Ph and C6H4); δC 15.9 and 21.5 (2Me), 126.9, 127.5,
128.1, 129.2, 131.4, 136.1, 138.7, 143.2 (Ph, C H ), 185.7 (C᎐N);
᎐
6
4
m/z 306 (CI, Mϩ, 100%), 258 (35), 155 (91), 105 (30), 91 (100),
77 (20), 65 (35); νmax(KBr)/cmϪ1 1596, 1546.
N-Acylbenzamide 8
References
To a solution of methylthioamidinium salt 3a (534 mg, 1.6
mmol) in dry acetonitrile were added silver nitrate (533 mg, 3.2
mmol) and water (1 mL). The mixture was stirred at room
temperature for 30 min and then concentrated under reduced
pressure. The crude product was flash-chromatographed (3:2
petroleum ether–ethyl acetate) to give 8 (42% yield) as white
crystals. Mp 110–111 ЊC (from diethyl ether) (Found: C, 64.56;
1 (a) D. L. Boger and S. M. Weinreb, in Hetero Diels–Alder
Methodology in Organic Synthesis, ed. H. H. Wasserman, Academic
Press, San Diego, 1987; (b) W. Carruthers, in Cycloaddition
Reactions in Organic Synthesis, ed. J. E. Baldwin and P. D. Magnus,
Pergamon Press, Oxford, 1990, vol. 8; (c) D. L. Boger, in
Comprehensive Organic Synthesis, ed. L. A. Paquette, Pergamon
Press, Oxford, 1991, vol. 5, p. 451; (d) H. Waldmann, Synthesis,
1994, 535; (e) L. Tietze and G. Kettschau, Top. Curr. Chem., 1997,
189, 1.
2 (a) J. C. Meslin and H. Quiniou, Bull. Soc. Chim. Fr., 1979, 116, 347;
(b) J. C. Rozé, J. P. Pradère, G. Duguay, A. Guevel, C. G. Tea and
H. Quiniou, Sulfur Lett., 1983, 1, 115; (c) C. G. Tea, J. P. Pradère
and H. Quiniou, J. Org. Chem., 1985, 50, 1545; (d) J. P. Pradère,
J. C. Rozé, H. Quiniou, R. Danion-Bougot, D. Danion and
L. Toupet, Can. J. Chem., 1986, 64, 597; (e) C. Cellerin, C. G. Tea,
J. P. Pradère, A. Guingant and P. Guenot, Sulfur Lett., 1988, 8,
205; ( f ) J. P. Pradère, F. Tonnard, A. Abouelfida, C. Cellerin,
M. Andriamanamihaja, B. Jousseaume, L. Toupet and P. Guénot,
Bull. Soc. Chim. Fr., 1993, 130, 610; (g) D. Dubreuil, J. P. Pradère,
N. Giraudeau, M. Goli and F. Tonnard, Tetrahedron Lett., 1995,
36, 237; (h) F. Purseigle, D. Dubreuil, A. Marchand, J. P. Pradère,
M. Goli and L. Toupet, Tetrahedron, 1998, 54, 2545.
3 A. Marchand, D. Mauger, A. Guingant and J. P. Pradère,
Tetrahedron: Asymmetry, 1995, 6, 853.
4 (a) J. Liebscher, M. Pätzel and Y. F. Kelboro, Synthesis, 1989, 672;
(b) C. Cellerin, J. P. Pradère, D. Danion and F. Tonnard, C. R. Acad.
Sci. Paris, 1991, 313, Série II, 517; (c) A. Rolfs and J. Liebscher,
J. Org. Chem., 1997, 62, 3480.
5 For a preliminary study about the heteroatom interconversion
reaction concept as shown in Scheme 1, see reference 4a. See also
for related work: (a) H. G. Gold, Angew. Chem., 1960, 72, 956;
(b) J. Liebscher and H. Hartmann, Synthesis, 1976, 403.
6 J. C. Meslin, A. Reliquet, F. Reliquet and C. G. Tea, C. R. Acad. Sci.
Paris, 1978, 286, Série C, 397.
7 (a) Semi empirical PM3 calculations were carried out with
SPARTAN software (4.0 version) on a Silicon Graphics Indy. For
PM3 calculations see: J. J. P. Stewart, Comput. Chem., 1989, 42, 12;
(b) F. Purseigle, PhD Thesis (30/01/97), University of Nantes.
8 J. Liebscher, Synthesis, 1988, 655.
H, 4.86; N, 9.40. C8H7NO2 requires C, 64.42; H, 4.73; N,
1
9.39%); δC 128.1, 129.0, 131.0, 133.9 (Ph), 164.6 (HCO, JCH
=
208 Hz), 166.8 (CO); the other spectral properties of 8 (1H
NMR and IR) were in full accordance with literature values.28
Compounds 12
Using a procedure similar to that described above for the syn-
thesis of 5a, compound 12 (two tautomer forms in solution,
vide infra) was obtained either from N-heterophenacylamidines
1b and 2b (50 and 80% yields, respectively) or from amidinium
salts 3b and 4b (60 and 85% yields, respectively) (Found: C,
67.60; H, 7.21; N, 12.35; O, 13.78. C13H16N2O2 requires C,
67.22; H, 6.94; N, 12.06; O, 13.78%); m/z 232 (Mϩ, 25%), 189
(25), 105 (100), 77 (57), 44 (41); νmax(film)/cmϪ1 1721, 1695 and
1623.
N-(1-Dimethylamino-3-oxobutylidene)benzamide. δH 2.17
(3H, s, Me), 2.9 and 3.1 (6H, 2s, NMe2), 3.8 (2H, s, CH-2), 7.2–
1
8.1 (5H, 2m, Ph); δC 31.8 (Me, JCH = 126.2 Hz), 39.3 (NMe2
1JCH = 142.2 Hz), 45.8 (CH2, JCH = 128.2 Hz), 128.9, 129.3
1
130.3, 138.5 (Ph), 164.0, 176.3, 201.7 (C᎐N, 2 C᎐O).
᎐
᎐
N-(1-Dimethylamino-3-oxobut-1-enyl)benzamide
(enamino
ketone form). δH 1.9 (3H, s, Me), 2.8 (6H, s, NMe2), 4.7 (1H, s,
CH), 13.4 (1H, s, NH), 7.3 and 7.4 (5H, 2m, Ph); δC 30.6 (Me,
1
1JCH = 126.2 Hz), 40.9 (NMe2, JCH = 142.2 Hz), 85.8 (C᎐CH,
᎐
1JCH = 159.4 Hz), 129.0, 129.5, 133.4, 137.1 (Ph), 158.5, 166.8,
195.3 (2 C᎐O, C᎐CH).
9 For a recent review on conversion of the thiocarbonyl group into the
carbonyl group, see: A. Corsaro and V. Pistarà, Tetrahedron, 1998,
54, 15027.
10 M. Avalos, R. Babiano, C. J. Duran, J. L. Jiménez and J. C. Palacios,
Tetrahedron Lett., 1994, 35, 477.
11 J. Barluenga and M. Thomas, in Advances in Heterocyclic
Chemistry, ed. A. R. Katritzky, Academic Press, San Diego, 1993,
vol. 57, p. 61.
12 H. Schaumann, in The chemistry of double-bonded functional groups,
ed. S. Patai, Interscience Publication, John Wiley and Sons,
New York, 1989, vol. 2, ch. 17, p. 1338.
᎐
᎐
N-(p-Tolylsulfonyl)-NЈ,NЈ-dimethylformamidine 13
Mp 113–114 ЊC (from light petroleum) (Found: C, 53.39; H,
6.29; N, 12.51; S, 14.47. C10H14N2O2S requires C, 53.08; H, 6.24;
N, 12.38; O, 14.14; S, 14.17%); δH 2.39 (3H, s, Me), 3.00 and
3.11 (6H, 2s, NMe2), 7.23–7.78 (4H, 2d, C6H4), 8.12 (1H, s,
1
CH᎐N); δ 21.4 (Me, JCH = 127 Hz), 35.4 and 41.4 (NMe2,
᎐
C
1JCH = 138.5 Hz), 126.4, 129.3, 139.6, 142.4 (C6H4), 159.1
(CH᎐N, JCH = 184 Hz); m/z 226 (Mϩ, 27%), 91 (73), 71 (100),
13 Selected torsion angles: N1–C2–N3–C4 equal to Ϫ153.76Њ in 6a and
123.47Њ in 6b; C2–N3–C4–N2 equal to Ϫ170.83Њ in 6a and 166.54Њ
in 6b.
1
᎐
65 (42), 44 (83); νmax(KBr)/cmϪ1 1626.
14 C. K. Johnson, ORTEP Report ORNL-3794, Oak Ridge National
Laboratory, Tenessee, USA, 1965.
N-(p-Tolylsulfonyl)-NЈ-[bis(methylthio)phenylmethyl]form-
amidine 14
15 S. N. Mazumdar and M. P. Mahajan, Synthesis, 1990, 417.
16 (a) P. Luthardt and E. U. Würthwein, Tetrahedron Lett., 1988, 29,
921; (b) S. N. Mazumdar and M. P. Mahajan, Tetrahedron, 1991,
47, 1473; (c) S. N. Mazumdar, S. Mukherjee, A. Z. Sharma,
D. Sengupta and M. P. Mahajan, Tetrahedron, 1994, 50, 7579; (d)
P. D. Dey, A. K. Sharma, P. V. Bharatam and M. P. Mahajan,
Mp 60–61 ЊC (from diethyl ether) (Found: C, 53.67; H, 5.10;
N, 7.35; S, 24.98. C17H20N2O2S3 requires C, 53.66; H, 5.30; N,
7.36; O, 8.41; S, 25.27%); δH 1.98 (6H, s, SMe), 2.42 (3H, s, Me),
6.91 (1H, br s, NH), 7.27–7.79 (9H, m, Ph and C6H4), 8.78 (1H,
J. Chem. Soc., Perkin Trans. 1, 1999, 2821–2828
2827