May 1998
SYNTHESIS
727
1
-(1-Chloro-o,2-dimethylpropyl)-4,5-dihydro-3-isopropyl-3,5,5-tri- 4,5-Dihydro-5,5-dimethyl-3,3-diphenyl-3H-pyrazole (12l):
methyl-3H-pyrazolium Hexachloroantimonate (11j):
From 11l (7.02 g, 10 mmol). The oily product was crystallized at
1
3
2
4
14,17
From 9 (R = R = i-Pr; R = R = Me)
(2.39 g, 10 mmol) and –15°C from pentane (15 mL) to afford pale yellow prisms (1.65 g,
isobutene (0.67 g, 12 mmol). Crystallization at –15°C from MeCN (8 66%); mp 70–72°C (dec).
mL)/Et O (4 mL) afforded a colorless crystalline powder (2.97 g,
2
5
0%); mp 149–151°C (dec).
rel-(3aS,4R, 7S, 7aR)-3a,4,5,6, 7, 7a-Hexahydro-4, 7-methano-3,3-
diphenyl-3H-indazole (12m):
Spiro{cyclohexane-1,3,-[rel-(3aS,4R, 9R, 9aR)-1-(1-chlorocyclohex-
yl)-3a,4, 9, 9a-tetrahydro-4, 9-methanobenzo[f]-3H-indazolium}
Hexachloroantimonate (11k):
From 11m (7.41 g, 10 mmol). The yellow powder was crystallized at
–15°C from Et O (8 mL) to afford a pale yellow powder (2.19 g,
2
76%); mp 154–156°C (dec).
1
2
3
4
11,12
From 9 (R , R = R , R = cyclohexyl)
(2.63 g, 10 mmol) and ben-
zonorbornene (1.71 g, 12 mmol). Crystallization at –15°C from
CH Cl (10 mL)/Et O (6 mL) afforded a colorless powder (3.94 g,
3
-Aza-2-azonia-2-[1-(2,4,6-trichlorophenyl)azo(1-methyleth-
2
2
2
yl)]bicyclo[2.2.1]hept-2-ene Hexachloroantimonate (14a):
A solution of SbCl (2.99 g, 10 mmol) in CH Cl (20 mL) was added
dropwise to a cold (–60°C) solution of 2,3-diazanorbornene (1.15 g,
12 mmol) and (1-chloro-1-methylethyl)azo(2,4,6-trichlorobenzene)
5
6%); mp 156–159 °C (dec).
5
2
2
3
8
1
1
-(1-Chlorocyclohexyl)-4,5-dihydro-5,5-dimethyl-3,3-diphenyl-3H-
pyrazolium Hexachloroantimonate (11l):
From 9 (R = R = Ph; R , R = cyclohexyl) (3.47 g, 10 mmol) and –60°C for 1 h, then at 0°C for 1 h, and finally at 23°C for 10 min.
isobutene (0.67 g, 12 mmol). Crystallization of the grey powder at Evaporation of the solvent afforded a yellow powder, which was crys-
(2.86 g, 10 mmol) in CH Cl (60 mL). The mixture was stirred at
2
2
1
2
3
4
11
–
15°C from CH Cl (14 mL)/Et O (6 mL) afforded a yellow crystal- tallized at –15 °C from CH Cl (32 mL)/Et O (16 mL) to furnish a yel-
2 2 2
2 2 2
line powder (4.99 g, 71%); mp 131–133 °C (dec).
low crystalline powder (5.16 g, 76%); mp 122–124°C (dec) (Table 2).
rel-(3aS,4R, 7S, 7aR)-1-( 1-Chlorocyclohexyl)-3a,4,5,6, 7, 7a-hexahy- 3-Aza-2-azonia-2-[1-(4-nitrophenyl)azo(1-methylethyl)]bicyclo-
dro-4, 7-methano-3,3-diphenyl-3H-indazolium Hexachloroanti-
[2.2.1]hept-2-ene Hexachloroantimonate (14b):
monate (11m):
From 2,3-diazanorbornene (1.15 g, 12 mmol) and (1-chloro-1-meth-
1
2
3
4
39,40
From 9 (R = R = Ph; R = R = cyclohexyl) (3.47 g, 10 mmol) and ylethyl)azo(4-nitrobenzene)
(1.82 g, 10 mmol) in the manner de-
norbornene (1.13 g, 12 mmol). The oily product crystallized at –l5°C scribed for 14a. The product was precipitated from the reaction
from CH Cl (10 mL)/Et O (6 mL) affording a yellow crystalline mixture with pentane (120 mL) to afford a yellow powder, which was
2
2
2
powder (5.04 g, 68%); mp 158–161°C (dec).
crystallized at –15 °C from MeCN (24 mL)/Et O (30 mL) to furnish a
2
yellow crystalline powder (3.60 g, 58%); mp 107–110°C (dec) (Table 2).
rel-(3aS,4R, 9R, 9aR)-1-(1-Chlorocyclohexyl)-3a,4,9, 9a-tetrahydro-
4
, 9-methano-3, 3-diphenylbenzo[f]-3H-indazolium Hexachloroanti- rel-(3aS,4R,7S,7aR)-3a,4,5,6,7,7a-Hexahydro-4,7-methano-3,3-
monate (11n):
dimethyl-1-[1-(2,4,6-trichlorophenylhydrazono)-1-propyl]-3H-
1
2
3
4
From 9 (R = R = Ph; R = R = cyclohexyl) (3.47 g, 10 mmol) and indazolium Picrate (15a); Typical Procedure:
benzonorbornene (1.71 g, 12 mmol). Crystallization at –l5°C from A solution of SbCl (2.99 g, 10 mmol) in CH Cl (20 mL) was added
5
2
2
CH Cl (20 mL)/Et O (4 mL) afforded a yellow crystalline powder dropwise to a cold (–60°C) solution of (1-chloropropyl)azo(2,4,6-
2
2
2
1
(5.24 g, 67%); mp 151–153°C (dec).
trichlorobenzene) (2.86 g, 10 mmol) and 12f (1.64 g, 10 mmol) in
CH Cl (60 mL). The mixture was stirred at –60°C for 1 h, then at
2
2
0
°C for 1 h, and finally at 23°C for 10 min. An aq solution of NaOH
4
,5-Dihydro-3H-pyrazoles 12, General Procedure:
A solution of NaHCO3 (8.40 g, 100 mmol) and NH3 (1.70 g,
00 mmol) in H O (50 mL) was added to a cold (0°C) solution of 11
(2.80 g, 70 mmol, in 100 mL of H O) was added slowly to the cooled
2
mixture (0°C). The mixture was stirred at 23°C for 15 min, filtered
and the aqueous phase was separated. Extraction of the aqueous phase
with CH Cl2 (60 mL), drying of the combined organic extracts
1
2
(10 mmol) in MeCN (50 mL). After stirring at 0°C for 2 h, the organic
phase was separated and the aqueous phase was extracted with MeCN
2
(Na SO filtration after addition of decolorizing carbon, and evapo-
(
(
2 ´ 30 mL). The combined organic phases were diluted with CH Cl
2 4),
2
2
ration of the filtrate afforded an orange oil, which was dissolved in
EtOH (20 mL). A saturated solution of picric acid in EtOH (28 mL)/
H O (12 mL) was added. At –15°C a yellow powder (4.69 g, 73%)
30 mL). The H O layer was separated, and the organic phase was
2
dried (Na SO ). Filtration after treatment with decolorizing carbon
and evaporation of the filtrate afforded 12 (Table 2).
2
4
2
crystallized; mp 135–137°C (dec) (Table 2).
4
,5-Dihydro-5-isopropyl-3,3,5-trimethyl-3H-pyrazole (12d):
From 11d (5.66 g, 10 mmol). The oily product was dissolved in pen- 4,5-Dihydro-3,3,4,5,5-pentamethyl-1-[1-(2,4,6-trichlorophenylhy-
tane (40 mL). Filtration after treatment with decolorizing carbon and drazono)propyl]-3H-pyrazolium Hexachloroantimonate (15b):
evaporation of the solvent afforded a yellow volatile oil (0.85 g, From 12h (1.40 g, 10 mmol) and (1-chloropropyl)azo(2,4,6-trichlo-
5
5%), which according to the NMR spectra contained small amounts robenzene) (2.86 g, 10 mmol) in the manner described for 15a. The
of CH Cl and MeCN. A correct elemental analysis was not obtained. yellow residue was stirred with Et O (120 mL) for 30 min. Decanta-
2
2
2
tion and crystallization of the residue at –15 °C from MeCN (20 mL)/
rel-(3aS,4R, 7S, 7aR)-3a,4,5,6, 7, 7a-Hexahydro-4, 7-methano-3,3-di- Et
methyl-3H-indazole (12f):
O (12 mL) furnished a yellow crystalline powder (3.68 g, 51%);
mp 146–148°C (dec) (Table 2).
2
From 11f (5.76 g, 10 mmol). Yield: 1.30 g (79%) of an orange volatile
oil, which according to the NMR spectra contained small amounts of
rel-(3aS,4R, 7S, 7aR)-3a,4, 5,6, 7, 7a-Hexahydro-4, 7-methano-3,3-
diphenyl-1-[1-(2,4,6-trichlorophenylhydrazono)propyl]-3H-indazo-
lium Hexachloroantimonate (15c):
CH Cl .
2
2
4
,5-Dihydro-3,3,4,5,5-pentamethyl-3H-pyrazole (12h):
From 12m (2.89 g, 10 mmol) in the manner described for 15b. The
From 11h (5.52 g, 10 mmol). The oily product was dissolved in pen- oily product was stirred in Et O (120 mL) for 12 h to afford an orange
2
tane (40 mL). Filtration after treatment with decolorizing carbon and powder. Crystallization at –15°C from CH Cl (25 mL)/CCl (15 mL)
2
2
4
evaporation of the solvent afforded an orange volatile oil (1.01 g, furnished an orange crystalline powder (4.89g, 56%); mp 165–168°C
2%), which according to the NMR spectra contained small amounts (dec). Red prisms suitable for X-ray structural analysis were obtained
of CH Cl and MeCN. by recrystallization from CHCl at 5°C (Table 2).
7
2
2
3