1282
B. Štefane, S. Polanc
LETTER
(8) (a) Millington, C. R.; Quarrell, R.; Lowe, G. Tetrahedron
1998, 39, 7201. (b) Stieber, F.; Grether, U.; Waldmann, H.
Angew. Chem. Int. Ed. 1999, 38, 1073. (c) Müller, G. H.;
Waldmann, H. Tetrahedron Lett. 1999, 40, 3549.
1H NMR (300 MHz, CDCl3): d = 7.57 (dd, J = 4.0, 9.5 Hz, 1
H), 8.46 (dd, J = 1.5, 9.5 Hz, 1 H), 8.72 (dd, 1 H). 7a: yellow
oil; Rf (light petroleum–EtOAc, 5:3) 0.25. IR (KBr): 2949,
1618, 1574, 1500, 1447, 1371, 1098, 976, 875, 771 cm–1. 1H
NMR (300 MHz, CDCl3): d = 4.17 (s, 3 H), 7.54 (ddd, J =
1.0, 7.0, 8.0 Hz, 1 H), 7.81 (ddd, J = 1.5, 7.0, 8.5 Hz, 1 H),
7.92 (ddd, J = 1.0, 1.0, 8.5 Hz, 1 H), 8.14 (ddd, J = 1.0, 1.5,
8.0 Hz, 1 H), 8.80 (s, 1 H). MS (CI): m/z (%) = 160 (100)
[M+], 131 (40), 103 (95). 7b: yellow oil; Rf (CH2Cl2–MeOH,
10:1) 0.40. IR (KBr): 2946, 1561, 1493, 1462, 1367, 1122,
832 cm–1. 1H NMR (300 MHz, CDCl3): d = 4.29 (s, 3 H),
7.78 (dd, J = 4.0, 8.5 Hz, 1 H), 8.28 (dd, J = 1.5, 8.5 Hz, 1
H), 8.87 (s, 1 H), 8.99 (dd, J = 1.5, 4.0 Hz, 1 H). MS (EI, 70
eV): m/z (%) = 161 (100) [M+], 104 (98), 77 (40). HRMS
(EI): m/z calcd for C8H7N3O: 161.0589; found: 161.0590.
(16) Košmrlj, J.; Kočevar, M.; Polanc, S. J. Chem. Soc., Perkin
Trans. 1 1998, 3917.
(d) Stieber, F.; Grether, U.; Waldmann, H. Chem. Eur. J.
2003, 9, 3270. (e) Stieber, F.; Grether, U.; Mazitschek, R.;
Soric, N.; Giannis, A.; Waldmann, H. Chem. Eur. J. 2003, 9,
3282.
(9) The products were analysed using MS spectrometry.
(10) Baciocchi, E.; Mei, S.; Rol, C. J. Org. Chem. 1978, 43, 2919.
(11) Typical Procedure: To a solution of CAN (2.193 g, 4
mmol) and 1,2-dibromotetrachloroethane (1.302 g, 4 mmol)
in MeOH (5 mL) was added 2,4-dinitrophenylhydrazine
(198 mg, 1 mmol) in one portion. The reaction mixture was
stirred at r.t. for an additional 5 min, evaporated to dryness
below 40 °C, treated with H2O (10 mL) and extracted with
CH2Cl2 (5 × 10 mL). The organic phase was dried over
anhyd Na2SO4 and concentrated under reduced pressure to
give a mixture of products (2a:3Br:3Cl = 50:7.5:1). The
mixture was purified by column chromatography (SiO2,
EtOAc–light petroleum, 1:10). 2a: orange solid (134 mg,
80%); Rf (light petroleum–EtOAc, 3:1) 0.34. 1H NMR (300
MHz, CDCl3): d = 7.87 (t, J = 8.0 Hz, 1 H), 8.60 (dd, J = 2.0,
8.0 Hz, 2 H), 9.08 (t, J = 2.0 Hz, 1 H). 3Br: yellow oil (24
mg, 10%); Rf (light petroleum–EtOAc, 3:1) 0.44. 1H NMR
(300 MHz, CDCl3): d = 8.04 (d, J = 9.0 Hz, 1 H), 8.32 (dd,
J = 2.5, 9.0 Hz, 1 H), 8.70 (d, J = 2.5 Hz, 1 H). 3Cl: yellow
oil (2 mg, 1%); Rf (light petroleum–EtOAc, 3:1) 0.64. 1H
NMR (300 MHz, CDCl3): d = 7.86 (d, J = 9.0 Hz, 1 H), 8.43
(dd, J = 5.5, 9.0 Hz, 1 H), 8.76 (d, J = 2.5 Hz, 1 H).
(12) Bernard, M. K.; Makosza, M.; Szafran, B.; Wrzeciono, U.
Liebigs Ann. Chem. 1989, 545.
(17) Huang, P. C.; Kosower, E. M. J. Am. Chem. Soc. 1968, 90,
2354.
(18) Nonhebel, D. C.; Walton, J. C. Free Radical Chemistry;
Cambridge University Press: Cambridge, 1974, 25.
(19) (a) Tschirret-Guth, R. A.; Ortiz de Montellano, P. R. J. Org.
Chem. 1998, 63, 9711. (b) Bergmann, H.; Strumpf, T.; Lyr,
H. Pestic. Sci. 1988, 23, 141.
(20) Forchiassin, M.; Risalti, A.; Russo, C. Tetrahedron 1981,
37, 2921.
(21) Representative Procedure for the Oxidation of Aryl
Hydrazinecarboxylates 4a–c: An aryl hydrazine-
carboxylate (1 mmol) was added at r.t. in one portion to a
solution of CAN (2.1 mmol) in MeOH (5 mL). The reaction
mixture was stirred at r.t. for an additional 5 min, evaporated
to dryness below 40 °C, treated with H2O (10 mL) and
extracted with CH2Cl2 (5 × 10 mL). The organic phase was
dried over anhyd Na2SO4 and concentrated under reduced
pressure to give the pure products 5a–c. 5a: ref. 19. 5b:
orange oil (213 mg, 94%); Rf (light petroleum–EtOAc, 3:1)
0.59. IR (NaCl): 2985, 1758, 1572, 1503, 1389, 1368, 1296,
1245, 1211, 1165, 1029, 977, 889, 863, 826, 748 cm–1. 1H
NMR (300 MHz, CDCl3): d = 1.48 (t, J = 7.0 Hz, 3 H), 2.48
(s, 3 H), 4.53 (q, J = 7.0 Hz, 2 H), 7.41 (d, J = 8.0 Hz, 1 H),
(13) Kobe, J.; Stanovnik, B.; Tiler, M. Tetrahedron 1968, 24,
239.
(14) Wentrup, C.; Crow, W. D. Tetrahedron 1970, 26, 4915.
(15) General Procedure for the Oxidation of Hydrazines and
Hydrazides: The hydrazine or hydrazide (1 mmol) was
added at r.t. within a period of 10–15 min to a solution of
CAN (4 mmol) in MeOH (5 mL). The reaction mixture was
stirred at r.t. for an additional 10–40 min, evaporated to
dryness below 40 °C, treated with H2O (10 mL) and
neutralised with NaHCO3 (pH ca. 7). After extraction with
CH2Cl2 (5 × 10 mL), the organic phase was dried over anhyd
Na2SO4 and concentrated under reduced pressure to give
dehydrazinated products 2. If necessary the products were
purified by column chromatography on SiO2. Products 2a–f,
8a and 8b were compared with the authentic samples. 2g:
yellow solid; Rf (light petroleum–EtOAc, 5:3) 0.43; mp 69–
72 °C (MeCN). IR (KBr): 3119, 1543, 1517, 1471, 1442,
1371, 1341, 1167, 1066, 1004, 849, 836, 762, 606, 566
cm–1. 1H NMR (300 MHz, CDCl3): d = 2.53 (s, 3 H), 3.87 (s,
3 H), 8.08 (s, 1 H). 2h: white solid; Rf (CH2Cl2–MeOH, 10:1)
0.39; mp 47–50 °C (light petroleum–EtOAc). IR (KBr):
3121, 3105, 1619, 1531, 1475, 1345, 1298, 1271, 1144,
1024, 928, 872, 797, 756, 635, 571 cm–1. 1H NMR (300
MHz, CDCl3): d = 7.02 (dd, J = 4.0, 9.0 Hz, 1 H), 7.78 (d,
J = 1.0 Hz, 1 H), 7.96 (dd, J = 1.0, 9.0 Hz, 1 H), 7.98–7.99
(m, 1 H), 8.30 (dd, J = 1.0, 9.0 Hz, 1 H). 2i: white solid; Rf
(CH2Cl2–MeOH, 10:1) 0.40; mp 98–102 °C (light
7.79 (dd, J = 2.0, 8.0 Hz, 1 H), 7.93 (d, J = 2.0 Hz, 1 H). 13
NMR (75.5 MHz, CDCl3): d = 14.0, 20.2, 64.3, 122.90,
122.95, 131.3, 135.3, 142.3, 150.4, 161.8. MS (CI): m/z
(%) = 225 (85) [M + 2]+, 178 (50), 150 (55), 122 (100).
HRMS (EI): m/z calcd for C9H11N3O4: 225.0750; found:
225.0759. 5c: orange oil (176 mg, 73%); Rf (light
C
petroleum–EtOAc, 5:1) 0.14. IR (NaCl): 2938, 1762, 1544,
1514, 1446, 1359, 1235 cm–1. 1H NMR (300 MHz, CDCl3):
d = 1.49 (t, J = 7.0 Hz, 3 H), 2.54 (s, 3 H), 4.05 (s, 3 H), 4.55
(q, J = 7.0 Hz, 2 H). 13C NMR (75.5 MHz, CDCl3): d = 13.2,
14.1, 38.8, 65.3, 144.1, 146.2, 160.7, 171.1. MS (CI): m/z
(%) = 243 (8) [M + 2]+, 125 (14), 67 (100). HRMS (EI): m/z
calcd for C8H13N5O4: 243.0968; found: 243.00968.
(22) Dimroth, K.; Tüncher, W. Synthesis 1977, 339.
(23) (a) Mencarelli, P.; Stegel, F. J. Org. Chem. 1985, 50, 5415.
(b) Higashino, T.; Uchida, M.; Hayashi, E. Chem. Pharm.
Bull. 1972, 20, 772.
(24) Kočevar, M.; Mihorko, P.; Polanc, S. J. Org. Chem. 1995,
60, 1466.
petroleum–EtOAc). IR (KBr): 3096, 1614, 1541, 1419,
(25) Gozzo, F. C.; Eberlin, M. N. J. Org. Chem. 1999, 64, 2188.
1370, 1348, 1327, 1255, 1130, 1087, 1011, 810, 764 cm–1.
Synlett 2008, No. 9, 1279–1282 © Thieme Stuttgart · New York