1. Isolation and stereostructures of citreoviral, citreodiol, and epicitreodiol
2. a) Kosemura, S.; Matsunaga, K.; Yamamura, S.; Kubota, M.; Ohba, S. Tetrahedron Lett., 1991, 32, 3543. b) Kosemura, S.; Matsunaga, K.; Yamamura, S. Chem. Lett., 1991, 1811. c) Kosemura, S.; Nagamatsu, H.; Yamamura, S. Bull. Chem. Soc. Jpn., 1992, 65, 926. d) Kosemura, S.; Miyata, H.; Matsunaga, K.; Yamamura, S. Tetrahedron Lett., 1992, 33, 3883. e) Kosemura, S.; Miyata, H.; Yamamura, S.; Albone, K.; Simpson, T.J. J. Chem Soc Perkin Trans 1 1994, 135. f) Kosemura, S.; Uotsu, S.; Yamamura, S.; Tetrahedron Lett., 1995, 36, 7481. g) Kosemura, S.; Matsuo, S.; Yamamura, S. Psytochemistry, 1996, 43, 1231.
3. Physical data for citreoazopyrone: a colorless oil; [α]D25 −0.1° (c = 0.5, CHCl3); C13H18N2O5 [m/z 282.1209 (M+)]; IR(film) 1715, 1650, and 1570 cm−1; 1H-NMR (CDCl3) δ 5.59 (1H, ddd, J=5.13, 2.56, 1.10, H-7), 5.47 (1H, s, H-2), 4.80 (1H, ddd, J= 18.30, 9.33, 2.56, Hβ-10), 4.54 (1H, ddd, J= 18.30, 4.94, 1.10, Hα-10), 4.13 (1H, d, J= 6.23, H-9), 3.83 (3H, s, 3-OMe), 3.29 (6H, s, 9-(OMe)2), 2.65 (1H, dddd, J= 9.33, 6.23, 5.13, 4.94, H-8), and 2.15 (3H, s); 13C-NMR (CDCl3) δ 170.4 (s, C-3), 163.3 (s, C-1), 153.5 (s, C-5), 110.1 (s, C-4), 104.7 (d, C-9), 89.3 (d, C-2), 87.2 (d, C-7), 79.7 (t, C-10), 56.3 (q, 3-OMe), 54.9 (q, 9-OMe), and 53.9 (q, 9-OMe), 38.4 (d, C-8), and 9.4 (q, C-6).
4. Physical data for 2: 0.0025%; a colorless powder, C9H10O4 [m/z 182.0576 (M+)]; 1H-NMR (CDCl3) δ 5.52 (1H, s), 3.86 (1H, dd, J= 4.2, 2.4 Hz), 3.85 (3H, s), 3.36 (1H, dd, J= 5.7, 2.4 Hz), 3.06 (1H, dd, J= 5.7, 4.2 Hz), and 2.06 (3H, s).
5. Physical data for 3: 0.0015%; a colorless powder; C10H12O4 [m/z 196.0736 (M+)]; 1H-NMR (CDCl3) δ 5.50 (1H, s), 3.85 (3H, s), 2.97 (1H, d, J= 5.6 Hz), 2.85 (1H, d, J= 5.6 Hz), 2.00 (3H, s), and 1.61 (3H, s).