2
64 Arroyo et al.
Finally 6a and 7a acted as fungicides against M.
gypseum as well as both yeasts assayed.
(8 days). Yeasts were grown in the same medium
and were incubated at 30 C for 36 h. Fungal cul-
◦
tures were maintained on malt extract broth plus 15 g
antibiotic medium (Bioxon) number 3 (Becton
Dickinson of M e´ xico, S.A. of C.V. Cuautitl a´ n Izcalli,
Carretera M e´ xico Queretaro Km. 37.5, Estado de
M e´ xico). The biological activity was assessed on the
basis of the growth rate for both filamentous fungi
and yeasts aqueous solutions [17].
EXPERIMENTAL
Toluene and n-hexane (Aldrich) were dried prior to
use (Na/benzophenone). The mercaptans (Aldrich)
were used as received. The bentonitic material was
obtained from Tonsil Mexicana and analyzed prior to
use with a Siemens D-5000 X-ray diffractomer using
Cu Kꢀ
1
radiation. Purified products were character-
ACKNOWLEDGMENT
1
ized by spectroscopic means: H NMR spectra were
recorded on a Varian Mercury-300 spectrometer, us-
ing CDCl as solvent and TMS as internal reference;
EIMS (70 eV) spectra, the HRMS and the CID-linked
scans data were obtained using JEOL MS AX 505
HA and MS-SM 102 mass spectrometers. Thin layer
chromatographic analyses were performed using
Merck precoated plates (silica gel 60 F254, 0.25 mm);
for the corresponding column chromatography
The authors thank Eva Hern a´ ndez Godinez
and Raymundo Gardu n˜ o Monroy for technical
assistance.
3
REFERENCES
[
1] Schmidt, B.; Lindman, S.; Tong, W.; Lindeberg, G.;
Gogoll, A.; Lai, Z.; Thornwall, M.; Synnergren, B.;
Nilsson, A.; Welch, C. J.; Sohtell, M.; Westerlund, C.;
Nyberg, F.; Karlen, A.; Hallberg, A. J Med Chem 1997,
(flash), silica gel Merck 230-400 mesh was employed.
The melting points were determinated on a Fisher–
Johns apparatus and are uncorrected. The supported
reagents were prepared according to a previously re-
ported procedure [15]. All the known compounds
4
0, 903–919.
[2] Li, K. W.; Wu, J.; Xing, W.; Simon, J. A. J Am Chem
Soc 1996, 118, 7237–7238.
[
3] Palmer, B. D.; Newcastle, G. W.; Thompson, A. M.;
Boyd, M.; Showalter, H. D. H.; Sercel, A. D.; Fry,
D. W.; Kraker, A. J.; Denny, W. A. J Med Chem 1995,
(see Tables 1 and 2) were identified by compari-
son with authentic samples, using physical (mp) and
spectroscopical data ( H NMR and EIMS) [16].
3
8, 58–67.
[4] Ramadas, K.; Srinivasan, N. Synth Commun 1995,
5, 227–234.
1
2
[
5] Wu, X.; Rieke, R. D.; Zhu, L. Synth Commun 1996,
26, 191–196.
Oxidative Coupling of Mercaptans
[6] Yiannios, C. N.; Karabinos, J. V. J Org Chem 1963, 28,
One hundred milligrams of each mercaptan and 100
3
246–3248.
mg of M(NO
3
)n/TAFF in 20 ml of toluene were placed
[7] Cornelis, A.; Depaye, N.; Gerstmans, A.; Laszlo, P.
in a round-bottomed flask (50 ml) equipped with a
condenser and gently refluxed for 3–12 h. The reac-
tion was monitored by TLC (n-hexane/EtOAc) each
hour. At the end of each reaction, the reaction mix-
ture was filtered over celite and washed with hot
toluene. Once the solvent had been evaporated un-
der vacuum, some of the residue (substrates 1–8)
were purified by preparative film chromatography
and crystallized from toluene.
Tetrahedron Lett 1983, 24, 3103–3106.
[
[
8] Zhong, P.; Guo, M. P. Synth Commun 2001, 31, 1825–
828.
1
9] Raghavan, S.; Rajender, A.; Joseph, S. C.; Rasheed,
M. A. Synth Commun 2001, 31, 1477–1480.
[10] Salehi, P.; Farrokhi, A.; Gholizadeh, M. Synth Com-
mun 2001, 31, 2777–2781.
[
11] Miranda, R.; Osnaya, R.; Gardu n˜ o, R.; Delgado, F.;
´
Alvarez, C.; Salm o´ n, M. Synth Commun 2001, 31,
587–1597; and refences therein.
1
[
[
[
12] Miranda, R.; Escobar, J.; Delgado, F.; Salm o´ n, M.;
Cabrera, A. J Mol Catal 1999, 150, 299–305; and
refences therein.
13] Obrador, E.; Castro, M.; Tamariz, J.; Zepeda, G.;
Miranda, R.; Delgado, F. Synth Commun 1998, 28,
Biological Assay
The following filamentous fungi were employed: A.
fumigatus, A. niger, A. candidus, and M. gypseum. The
yeast strains used were Candida albicans and Cryp-
tococcus neoformans. They were obtained from Lab-
oratorio de Microbiolog ı´ a, FESC-UNAM, M e´ xico.
Filamentous fungi were inoculated in 250 ml
Erlenmeyer flasks with 50 ml growth medium malt
extract broth (15 g malt extract and 5 g peptone in 1 l
distilled water). Then, each solution was incubated
4
649–4663; and refences therein.
14] (a) Tonsil Actisil FF (TAFF), a commercial Mexican
bentonitic clay, is available from Tonsil Mexicana S.
A. de C. V. Mexico City, Mexico at US$ 1.30/kg. When
examined with X-ray fluorescence, this clay proved
to have the following composition (in percent): SiO2,
7
4.5; Al O , 9.3; MgO, 0.4; Fe O , 1.3; CaO, 4.0;
2 3 2 3
K O, 0.4; TiO , 0.4; H O, 9.7. When X-ray thermod-
2
2
2
iffractograms were run, the laminar structure was
◦
found to be unstable above 150 C. Quartz and cristo-
◦
at 30 C until a strong mycelial growth was obtained
balite are also important components in the clay