M. De Lucia et al. / Tetrahedron 62 (2006) 1273–1278
1277
mixture, the residue was treated with acetic anhydride
1 mL) and pyridine (50 mL) at room temperature for 16 h
and then purified by preparative TLC (eluent cyclohexane/
Barone is gratefully acknowledged. We thank the ‘Centro
Interdipartimentale di Metodologie Chimico-Fisiche’
(CIMCF, University of Naples Federico II) for NMR,
mass spectroscopy, and computational facilities and Mrs.
Silvana Corsani for technical assistance.
(
ethyl acetate 6:4) to give the triacetyl derivative of 5 (Rf
0
the pentaacetyl derivative of 6 (R 0.46, 20 mg, 21% yield,
.61, 30 mg, 14% yield, O98% pure by NMR analysis) and
f
O98% pure by NMR analysis).
Compound 5 (triacetyl derivative). UV l
2
(CH OH):
3
max
1
68 nm; H NMR d (ppm): 2.15 (s, 3H), 2.25 (s, 3H), 2.26
References and notes
1
s, 3H), 2.29 (s, 3H), 6.95 (s, 1H), 7.04 (s, 1H); C NMR
3
(
d (ppm): 15.9 (CH ), 20.6 (2!CH ), 20.7 (CH ), 117.2 (CH),
3
3
3
1. Keys, A. Am. J. Clin. Nutr. 1995, 61, 1321S–1323S.
2. Owen, R. W.; Haubner, R.; Wurtele, G.; Hull, E.;
Spiegelhalder, B.; Bartsch, H. Eur. J. Cancer Prev. 2004,
13, 319–326.
1
24.9 (CH), 128.7 (C), 139.4 (C), 140.0 (C), 146.4 (C), 168.0
C), 168.2 (C), 168.6 (C); ESIC/MS: m/z 267 ([MCH] ,
C
(
C C
00), 289 ([MCNa] , 57), 305 ([MCK] , 4); EI/HRMS
1
calculated mass for C H O [M] 266.0790, found m/z
C
1
3 14 6
3. Tuck, K. L.; Hayball, P. J. J. Nutr. Biochem. 2002, 13,
636–644.
2
66.0795.
4
. Visioli, F.; Bellomo, G.; Galli, C. Biochem. Biophys. Res.
Commun. 1998, 247, 60–64.
Compound 6 (pentaacetyl derivative). UV l
(CH OH):
3
max
1
2
3
68 nm; H NMR d (ppm): 1.94 (s, 3H), 1.96 (s, 3H), 2.11 (s,
H), 2.21 (s, 3H), 2.25 (s, 3H), 2.28 (s, 3H), 2.29 (s, 3H), 6.88
5. Owen, R. W.; Mier, W.; Giacosa, A.; Hull, W. E.;
Spiegelhalder, B.; Bartsch, H. Food Chem. Toxicol. 2000,
38, 647–659.
1
3
(
s, 1H), 7.07 (s, 1H), 7.14 (s, 1H); C NMR d (ppm): 16.2
CH ), 19.1 (CH ), 19.9 (2!CH ), 20.6 (3!CH ), 124.2 (2!
(
6. Vogna, D.; Pezzella, A.; Panzella, L.; Napolitano, A.; d’Ischia, M.
Tetrahedron Lett. 2003, 44, 8289–8292.
3
3
3
3
CH), 125.1 (CH), 128.4 (C), 129.5 (C), 129.8 (C), 136.4 (C),
39.3 (C), 139.7 (C), 140.3 (C), 141.7 (C), 144.8 (C), 168.2
1
7. O’Dowd, Y.; Driss, F.; My-Chan Dang, P.; Elbim, C.;
Gougerout-Pocidalo, M.; Pasquier, C.; El-Benna, J. Biochem.
Pharmacol. 2004, 68, 2003–2008.
C
5!C); ESIC/MS: m/z 473 ([MCH] , 100), 505 ([MC
(
C
Na] , 23); EI/HRMS calculated mass for C H O
24 10
2
4
C
M] 472.1369, found m/z 472.1373
[
8. Roche, M.; Dufour, C.; Mora, N.; Dangles, O. Org. Biomol.
Chem. 2005, 3, 423–430.
3
2
.4. Reaction of 4-methyl-1,2-benzoquinone with
-hydroxy-5-methyl-1,4-benzoquinone
9. Pezzella, A.; Lista, L.; Napolitano, A.; d’Ischia, M. Tetrahedron
Lett. 2005, 46, 3541–3544.
1
0. Adler, E.; Magnusson, R. Acta Chem. Scand. 1959, 13,
505–519.
A solution of the triacetyl derivative of 5 (6 mg, 23 mmol)
in acetone (100 mL) was added to 0.025 M sodium
phosphate buffer (pH 12) (12 mL) that had been
previously purged with a stream of argon for 15 min.
After 2 min, the solution was acidified to pH 7 with
NaH PO !H O (29 mg) and treated with NaIO (5 mg,
11. Plesnicar, B. In The Chemistry of Peroxides; Patai, S., Ed.;
Wiley: New York, 1983; pp 573–578.
12. Napolitano, A.; Crescenzi, O.; Pezzella, A.; Prota, G. J. Med.
Chem. 1995, 38, 917–922.
2
4
2
4
13. Teichner, H.; Weil, H. Chem. Ber. 1905, 38, 3376–3377.
14. Weitz, E.; Schobbert, H.; Seibert, H. Chem. Ber. 1935, 68,
1163–1168.
2
3 mmol) predissolved in H O (8 mL). After 30 s, a
2
10
solution of 4-methyl-1,2-benzoquinone (3 mg, 23 mmol)
in acetone (145 mL) was added and after 3 min the
mixture was worked-up, acetylated and analyzed as
reported under the general procedure.
15. Wehrli, P. A.; Pigott, F.; Fischer, U.; Kaiser, A. Helv. Chim.
Acta 1972, 55, 3057–3061.
16. Bailey, S. I.; Ritchie, I. M. Electrochim. Acta 1985, 30,
3
–12.
1
7. Critchlow, A.; Haslam, E.; Haworth, R. D.; Tinker, P. B.;
Waldron, N. M. Tetrahedron 1967, 23, 2829–2847.
8. Palumbo, A.; d’Ischia, M.; Misuraca, G.; Prota, G. Pigment
Cell Res. 1992, 2, 299–303.
4
. Computational methods
1
Quantum-mechanical computations were carried out with
the Gaussian03 revision B.05 program using the PBE0
2
0
19. Capasso, R.; Evidente, A.; Avorio, S.; Solla, F. J. Agric. Food
Chem. 1999, 47, 1745–1748.
2
1
density functional. The 6–311CG(d,p) basis set was
used for geometry optimisations. Frontier orbitals were
calculated at the HF/6-31CG(d,p) level. The most recent
20. Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.;
Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.;
Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.;
Scalmani; G.; Cossi, M.; Rega, N.; Petersson, G. A.;
Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.;
Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.;
Cross, J. B.; Adamo, C.; Jaramillo, J.; Gomperts, R.;
Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.;
Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.;
Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.;
Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.;
2
2
version of the polarizable continuum model (PCM) was
used to model the effects of the solvent medium.
Acknowledgements
This study was carried out in the frame of the MIUR
projects ‘Sostanze naturali ed analoghi sintetici con
attivit a` antitumorale’ (PRIN 2003) and ‘Tecniche
Integrate di Decontaminazione’ (TIDe). Computational
analysis by professors Orlando Crescenzi and Vincenzo