G. I. Graf et al. / Tetrahedron 58 (2002) 9095–9100
9099
(Mþz). Anal. calcd for C22H24N2O8: C, 59.45; H, 5.44; N,
6.30. Found: C, 59.22; H, 5.73; N, 6.41.
4.3.3. 4,7-Dichloro-5-methyl-1,10-phenanthroline (4c).
Yellow solid (35%): mp .1808C (EtOAc, decomp.); Rf
0.18 (EtOAc); IR (nujol): 869, 1085, 1210, 1551, 1570,
1686 cm21; 1H NMR (CDCl3, 60 MHz) d 3.10 (s, 3H), 7.69
(d, J¼4.8 Hz, 2H), 7.99 (s, 1H), 9.00 (d, J¼4.8 Hz, 2H); 13C
NMR (CDCl3, 67.8 MHz) d 26.4, 124.0, 124.8, 126.4,
127.1, 134.8, 141.8, 143.0, 146.1, 147.2, 148.2, 149.4; MS
(EI) 263 (Mþz); HRMS (EI) calcd for C13H8Cl2N2: (Mþz)
262.0065, found (Mþz) 262.0059. Anal. calcd for
C13H8Cl2N2: C, 59.34; H, 3.06; N, 10.65. Found: C,
59.32; H, 3.25; N, 10.28.
4.2.10. 2,5-Dimethyl-1,4-bis-[(2,2-dimethyl-4,6-dioxo-
1,3-dioxan-5-ylidenemethyl)amino]benzene (17a). Yellow
crystalline solid (55%): mp .2628C (DMF, decomp.); IR
;
(KBr): 1670, 1726, 3164 cm21 1H NMR (CF3COOD,
200 MHz) d 1.75 (s,12H), 2.41 (s, 6H), 7.41 (s, 2H), 8.81 (d,
J¼14.6 Hz, 2H), 11.47 (d, J¼14.6 Hz, 2H); 13C NMR
(CF3COOD, 50 MHz) d 16.2, 25.9, 86.6, 109.4, 121.1,
127.2, 136.3, 155.7 169.3, 169.6; MS (EI) 444 (Mþz). Anal.
calcd for C22H24N2O8: C, 59.45; H, 5.44; N, 6.30. Found: C,
59.49; H, 5.29; N, 6.35.
4.3.4. 4,7-Dichloro-5,6-dimethyl-1,10-phenanthroline
(4d). Yellow solid (33%): mp .1808C (EtOAc, decomp.);
Rf 0.18 (EtOAc); IR (nujol): 872, 1084, 1221, 1555, 1569,
1682 cm21; 1H NMR (CDCl3, 60 MHz) d 2.90 (s, 6H), 7.62
(d, J¼4.8 Hz, 2H), 8.90 (d, J¼4.8 Hz, 2H); 13C NMR
(CDCl3, 67.8 MHz) d 20.8, 126.6, 127.6, 132.1, 146.2,
147.1, 148.3; MS (EI) 277 (Mþz); HRMS (EI) calcd for
C14H10Cl2N2: (Mþz) 276.0221, found (Mþz) 276. 0219.
4.2.11. 2,5-Dichloro-1,4-bis-[(2,2-dimethyl-4,6-dioxo-1,3-
dioxan-5-ylidenemethyl)amino]benzene (17b). Yellow
crystalline solid (82%): mp .2408C (DMF, decomp.); IR
;
(KBr): 1676, 1728, 3146 cm21 1H NMR (CF3COOD,
200 MHz) d 1.75 (s, 12H), 7.81 (s, 2H), 8.86 (d, J¼14.2 Hz,
2H), 11.76 (d, J¼14.2 Hz, 2H); 13C NMR (CF3COOD,
50 MHz) d 26.0, 88.4, 109.6, 119.9, 126.4, 134.7, 154.6,
168.6, 169.2; MS (EI) 280 (base peak), 282 (M-2H)þ. Anal.
calcd for C20H18Cl2N2O8: C, 49.50; H, 3.73; N, 5.77.
Found: C, 49.46; H, 3.84; N, 6.10.
4.3.5. 4,7-Dichloro-5,6-dimethoxy-1,10-phenanthroline
(4e). Yellow solid (32%): mp 2168C (EtOAc); Rf 0.12
(EtOAc); IR (nujol): 969, 1078, 1292, 1539, 1588 cm21; 1H
NMR (CDCl3, 60 MHz) d 4.40 (s, 6H), 7.72 (d, J¼4.8 Hz,
2H), 8.98 (d, J¼4.8 Hz, 2H); 13C NMR (CDCl3, 22.4 MHz)
d 61.4, 126.7, 127.6, 128.5, 139.7, 146.7, 148.9; MS (EI)
309 (Mþz). Anal. calcd for C14H10Cl2N2O2: C, 54.39; H,
3.26; N, 9.06. Found: C, 54.60; H, 3.13; N, 8.97.
4.3. General procedure for the preparation of
diazatricycles from phenylenediamine-bis(methylene
Meldrum’s acid) derivatives
The corresponding bis-adduct 2a–f, 7, 12a or 17a (1 mmol)
was refluxed in diphenyl ether (20 mL) for 30 min. In the
case of 12b and 17a, the reflux time had to be kept below
5 min. The mixture was allowed to cool, the dione
precipitated upon the addition of hexanes, filtered, washed
with hexanes and added to phosphoryl chloride (4 mL). The
resulting mixture was refluxed for 30 min under N2, poured
onto ice and water (40 mL), neutralized with 10% NaOH,
extracted with CH2Cl2 (3£100 mL) and the combined
organic layers dried (MgSO4). Rotary evaporation and
chromatography gave the diazatricycles 4a–e, 5, 9, 13a,b,
18 and 20a (or b).
4.3.6. 4,7-Dibromo-1,10-phenanthroline (5a).12 The same
procedure as above but heating phenanthrolone 3a (0.21 g,
1 mmol) in molten phosphoryl bromide (6.0 g, 21 mmol) at
808C gave compound 5a (0.19 g, 58%) as a colourless solid:
mp .2208C (EtOAc, decomp.); Rf 0.15 (EtOAc); IR
(nujol): 1058, 1212, 1414, 1539, 1569 cm21 1H NMR
;
(CDCl3, 60 MHz) d 7.94 (d, J¼4.8 Hz, 2H), 8.28 (s, 2H),
8.96 (d, J¼4.8 Hz, 2H); 13C NMR (CDCl3, 22.4 MHz) d
126.2, 127.7, 128.4, 134.4, 146.7, 150.2; MS (EI) 338 (Mþz).
Anal. calcd for C12H6Br2N2: C, 42.64; H, 1.79; N, 8.29.
Found: C, 42.79; H, 1.70; N, 8.04.
4.3.1. 4,7-Dichloro-1,10-phenanthroline (4a).8 Colourless
solid (77%): mp 2538C (EtOAc); Rf 0.17 (EtOAc); IR
4.3.7. 4,5,10-Trichloro-1,7-phenanthroline (9). Colour-
less solid (46%): mp 187–1908C (hexane/EtOAc/CHCl3,
4:1:1); IR (KBr): 778, 832, 912, 1146, 1406, 1544 cm21; 1H
NMR (CDCl3, 200 MHz) d 7.71 (d, J¼4.7 Hz, 2H), 8.22 (s,
1H), 8.81 (d, J¼4.7 Hz, 1H), 8.91 (d, J¼4.7 Hz, 1H); 13C
NMR (CDCl3, 50 MHz) d 122.7, 123.0, 126.0, 126.4, 131.7,
132.9, 141.7, 143.7, 147.3, 148.5, 150.4, 151.0; MS (EI) 282
(Mþz). Anal. calcd for C12H5Cl3N2: C, 50.83; H, 1.78; N,
9.88. Found: C, 50.62; H, 1.73; N, 9.70.
(nujol): 876, 1081, 1217, 1544, 1574 cm21 1H NMR
;
(CDCl3, 60 MHz) d 7.70 (d, J¼4.8 Hz, 2H), 8.24 (s, 2H),
9.06 (d, J¼4.8 Hz, 2H); 13C NMR (CDCl3, 22.4 MHz) d
123.1, 123.8, 126.7, 142.8, 146.9, 150.2; MS (EI) 248
(Mþz); HRMS (EI) calcd for C12H6Cl2N2: (Mþz) 247.9908,
found (Mþz) 247.9915. Anal. calcd for C12H6Cl2N2:
C, 57.86; H, 2.43; N, 11.25. Found: C, 57.94; H, 2.40; N,
11.59.
4.3.8. 1,10-Dichloro-4,7-phenanthroline (13a).3a Colour-
less solid (33%): mp 234–2368C (EtOAc), 1H NMR
(CDCl3, 200 MHz) d 7.57 (d, J¼4.8 Hz, 2H), 8.04 (s, 2H),
8.82 (d, J¼4.8 Hz, 2H); 13C NMR (CDCl3, 50 MHz) d
122.6, 132.4, 143.0, 149.8, 150.9. Anal. calcd for
C12H6Cl2N2: C, 57.86; H, 2.43; N, 11.25. Found: C,
57.71; H, 2.53; N, 11.12.
4.3.2. 4,5,7-Trichloro-1,10-phenanthroline (4b). Yellow
solid (34%): mp .2008C (EtOAc, decomp.); Rf 0.17
(EtOAc); IR (nujol): 878, 944, 1087, 1233, 1568,
1594 cm21
;
1H NMR (CDCl3, 60 MHz) d 7.72 (d, J¼
4.8 Hz, 2H), 8.26 (s, 1H), 9.00 (d, J¼4.8 Hz, 2H); 13C NMR
(CDCl3, 67.8 MHz) d 124.5, 125.6, 126.1, 127.4, 129.7,
141.5, 142.4, 146.1, 148.7, 150.2, 150.5; MS (EI) 283
(Mþz); HRMS (EI) calcd for C12H5Cl3N2: (Mþz) 281.9518,
found (Mþz) 281.9522. Anal. calcd for C12H5Cl3N2: C,
50.83; H, 1.78. Found: C, 51.17; H, 2.07.
4.3.9. 1,10-Dichloro-5,6-dimethyl-4,7-phenanthroline
(13b). Brown solid (78%): mp 172–1748C (CHCl3); IR
(KBr): 768, 838, 1326, 1456, 1554 cm21; 1H NMR (CDCl3,