J. S. Yadav et al. / Tetrahedron Letters 45 (2004) 7507–7509
7509
2
3
. Duthaler, R. O. Angew. Chem., Int. Ed. 2003, 42, 975–978.
. (a) Marigo, M.; Juhl, K.; Jorgensen, K. A. Angew. Chem.,
Int. Ed. 2003, 42, 1367–1369; (b) Kumaragurubaran, N.;
Juhl, K.; Zhuang, W.; Bogevig, A.; Jorgensen, K. A. J. Am.
Chem. Soc. 2002, 124, 6254–6255.
water and extracted with ethyl acetate. The organic layers
were dried over anhydrous Na SO and purified by column
2
4
chromatography to afford the pure a-hydrazino ketone.
4
Spectral data for selected compounds: 3a: Solid, mp 84ꢁC
[Ref. 4 (80–81ꢁC)], IR (KBr): m 3392, 2992, 2376, 1728,
1496, 1376, 1240, 1064, 784cm . H NMR (300MHz,
À1
1
4
. (a) Nelson, J. H.; Howells, P. N.; DeLullo, G. C.; Landen,
G. L.; Henry, R. A. J. Org. Chem. 1980, 45, 1246; (b)
Meseguer, M.; Moreno-Manas, M.; Vallribera, A. Tetra-
hedron Lett. 2000, 41, 4093.
CDCl ): d 1.25–1.45 (m, J = 7.01Hz, 9H), 2.25 (s, 3H),
3
4.13–4.36 (m, J = 7.01Hz, 6H), 6.75 (s, 1H), 12.10 (br s, 1H,
1
3
13
3
NH). C NMR (proton decoupled C in CDCl ; 75MHz):
5. Cornelis, A.; Laszlo, P. Synlett 1994, 155–161.
6. (a) Abramovitch, R. A. Org. Prep. Proc. Int. 1991, 23, 685;
d 13.8, 13.9, 14.3, 22.7, 61.2, 61.6, 63.1, 107.5, 154.7, 155.9,
169.6, 194.6. EIMS: m/z: 304 [M ], 262, 232, 190, 158, 144,
+
(
b) Caddick, S. Tetrahedron 1995, 51, 10403; (c) Loupy, A.;
20 2 7
117, 90. [Calcd for C12H N O (304.3024): C, 47.37; H,
Petit, A.; Hamelin, J.; Texier-Boullet, F.; Jacquault, P.;
Mathe, D. Synthesis 1998, 1213; (d) Varma, R. S. Green
Chem. 1999, 43.
6.62; N, 9.21. Found: C, 47.40; H, 6.60; N, 9.23%.]
Compound 3b: Solid, mp 89ꢁC, IR (KBr): m 3280, 3008,
2952, 2384, 1752, 1712, 1664, 1504, 1320, 1216, 1064,
À1
1
7
. (a) Yadav, J. S.; Reddy, B. V. S. Tetrahedron Lett. 2002, 43,
1
768cm
J = 6.79, 7.55Hz, 9H), 4.10–4.40 (m, J = 4.53, 6.79, 7.55Hz,
. H NMR (300MHz, CDCl ): d 1.20–1.40 (m,
3
905; (b) Yadav, J. S.; Reddy, B. V. S.; Madan, Ch.;
Kumar, G. M. Synlett 2001, 1781; (c) Yadav, J. S.; Reddy,
B. V. S.; Rasheed, M. A.; Kumar, H. M. S. Synlett 2000,
1
8H), 6.70 (s, 1H), 12.0 (br s, 1H, NH). C NMR (proton
3
1
3
3
decoupled C in CDCl ; 75MHz): d 13.9, 14.1, 14.3, 38.8,
4
2
87; (d) Yadav, J. S.; Reddy, B. V. S. New J. Chem. 2000,
4, 489.
61.9, 62.2, 63.5, 108.0, 156.0, 169.2, 170.8, 197.1. EIMS:
m/z: 338 [M ], 266, 218, 190, 144, 115, 90. [Calcd for
+
8
. (a) Microwave irradiation: 1,3-Dicarbonyl compound
1.0mmol), diethyl azodicarboxylate (1.2mmol) and
C H ClN O (338.7474): C, 42.55; H, 5.65; N, 8.27.
1
2
19
2
7
4
(
InCl
Found: C, 42.60; H, 5.63; N, 8.29%.] Compound 3f:
Solid, mp 123ꢁC [Ref. 4 (114–116ꢁC)], IR (KBr): m 3264,
9
(3wtequiv of 1,3-dicarbonyl compound) were
3
/SiO
2
À1
admixed in an Erlenmeyer flask and subjected to microwave
irradiation using a BPL, BMO-800T domestic oven oper-
ated at 450W for the appropriate time (see Table 1). On
completion, the reaction mixture was filtered and washed
with dichloromethane (2 · 10mL). Removal of the solvent
under reduced pressure followed by purification on silica
gel (Merck, 100–200 mesh, ethyl acetate–hexane 1:9)
afforded the pure a-hydrazino ketone. (b) Conventional
method: A mixture of 1,3-dicarbonyl compound (1.0mmol),
2992, 2864, 1760, 1696, 1600, 1520, 1312, 1056, 800cm
.
1
H NMR (300MHz, CDCl
6H), 2.10–2.28 (s, 6H), 4.12–4.32 (m, J = 7.01Hz, 4H),
3
): d 1.23–1.45 (t, J = 7.01Hz,
1
6.85 (s, 1H), 7.30 (br s, 1H, NH). C NMR (proton
3
1
3
decoupled C in CDCl ; 75MHz): d 14.3, 14.4, 22.0, 62.2,
3
+
63.4, 117.9, 155.8, 156.3, 191.9. EIMS: m/z: 274 [M ], 233,
18 2 6
202, 113, 90, 43. [Calcd for C11H N O (274.2759): C,
48.17; H, 6.62; N, 10.21. Found: C, 48.15; H, 6.62; N,
10.23%].
diethyl azodicaboxylate (1.2mmol) and InCl
3
(30mol%) in
9. The catalyst (InCl
(1g, Aldrich, 230–400 mesh) to a stirred solution of InCl
3 2
/SiO ) was prepared by adding silica gel
toluene (10mL) was stirred at reflux for the appropriate
time (see Table 1). After completion of the reaction as
indicated by TLC, the reaction mixture was diluted with
3
(0.3mmol) in dichloromethane (5mL) followed by evap-
oration of the solvent in vacuo.