7H-Naphtho(1,2,3-ij)(2,7)naphthyridin-7-one → 4-Bromosampangine

HRID 483833Notes

Reaction equation

HRID 483833 reaction equation
C1C=CC2[C:17](=[O:18])[C:16]3C4C(C=CN=3)=CC=NC=4C=2C=1.[Br:19][C:20]1[C:29]2[C:24]3=[C:25]([C:30]4[C:35]([C:36](=[O:37])[C:23]3=[N:22][CH:21]=1)=[CH:34][CH:33]=[CH:32][CH:31]=4)[N:26]=[CH:27][CH:28]=2.C1C=C[NH+]=CC=1.Br[Br-]Br>C(Cl)(Cl)Cl>[CH:32]1[CH:31]=[C:30]2[C:25]3[C:24]4[C:23]([C:36](=[O:37])[C:35]2=[CH:34][CH:33]=1)=[N:22][CH:21]=[C:20]([Br:19])[C:29]=4[CH:28]=[CH:27][N:26]=3.[CH3:16][CH2:17][O:18][C:21]1[N:22]=[C:23]2[C:24]3[C:25]([C:30]4[C:35]([C:36]2=[O:37])=[CH:34][CH:33]=[CH:32][CH:31]=4)=[N:26][CH:27]=[CH:28][C:29]=3[C:20]=1[Br:19]

Participants

5

Reactant 2

HCID 3871957H-Naphtho(1,2,3-ij)(2,7)naphthyridin-7-one2×HCID 99048014-Bromosampangine

Product 2

HCID 99048014-BromosampangineYield 64%HCID 103161514-Bromo-5-ethoxysampangineYield 1%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

Electrophilic Bromination of Sampangine: Preparation of 4-Bromo-7H-naphtho[1,2,3-ij] [2,7]naphthyridin-7-one [4-Bromosampangine, 5] and 4-Bromo-5-ethoxy-7H-naphtho[1,2,3-ij][2,7]naphthyridin-7-one[4-Bromo-5-ethoxysampangine, 20]. A mixture of pyridinium bromide perbromide (4.80 g, 15.0 mmol) and sampangine (2.32 g, 10.0 mmol) in CHCl3 (100 mL) was heated at reflux for 24 h. After cooling, the mixture was poured into a separatory funnel and washed with saturated aqueous NaHCO3 solution (2×250 mL). The organic layer was dried (K2CO3) and concentrated to dryness. The residual solids were subjected to flash silica gel chromatography while eluting with CHCl3 to give pure 4-bromosampangine (5) (2.00 g, 64%) and 4-bromo-5-ethoxysampangine (20) (0.05 g, 1%). An analytical sample of 20 was obtained by crystallization from CHCl3. Compound 5: mp 244°-246° C.; IR (KBr) 1670, 1590, 1400, 1320, 1310, 1275, 1230, 980, 790, 755, 720 cm-1 ; 1H NMR (CDCl3) δ 7.72 (ddd, 1H, J=7.9, 7.9, 1.4 Hz), 7.86 (ddd, 1H, J=7.9, 7.9, 1.4 Hz), 7.96 (d, 1H, J=5.9 Hz), 8.46 (dd, 1H, J=7.9, 1.4 Hz), 8.85 (dd, 1H, J=7.9, 1.4 Hz), 8.99 (d, 1H, J=5.9 Hz), 9.28 (s,1H); 13C NMR (CDCl3) 118.3 (1), 120.5 (0), 123.7 (0), 125.8 (1), 128.7 (1), 131.8 (1), 132.3 (0), 135.0 (1), 135.1 (0), 138.6 (0), 146.7 (0), 148.6 (1), 150.2 (1), 151.7 (0), 181.6 (0) ppm; Anal. (exact mass, HREIMS) calcd for C15H7BrN2O m/e 309.9741, found 309.9747; Anal. calcd for C15H7BrN2O: C 57.90, H 2.27, N 9.00; found C 57.70, H 2.27, N 9.26. Compound 20: mp 200°-201° C.; IR (KBr) 1670, 1592, 1570, 1430, 1382, 1365, 1330, 1270, 1212, 1080, 1070, 1042, 980, 845, 762, 755, 720, 710, 635 cm-1 ; 1H NMR (CDCl3) δ 1.56 (t, 3H, J=7.1 Hz), 4.79 (q, 2H, J=7.1 Hz), 7.67 (ddd, 1H, J=7.3, 7.3, 1.4 Hz), 7.79 (ddd, 1H, J=7.3, 7.3, 1.4 Hz), 7.82 (d, 1H, J=6.1 Hz), 8.36 (dd, 1H, J=7.3, 1.4 Hz), 8.72 (d, 1H, J=6.1 Hz), 8.75 (dd, 1H, J=7.3, 1.4 Hz); 13C NMR (CDCl3) 14.6 (3), 64.7 (2), 107.4 (0), 117.5 (0), 117.8 (1), 125.5 (1), 128.2 (1), 131.4 (1), 132.2 (0), 134.5 (1), 135.0 (0), 140.9 (0), 144.6 (0), 147.2 (1), 151.7 (0), 159.9 (0), 181.4 (0) ppm; Anal. calcd for C17H11BrN2O: C 57.48, H 3.12, N 7.88; found C 57.09, H 3.37, N 7.75.

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 24 h
  3. temperatureAfter cooling
  4. additionthe mixture was poured into a separatory funnel
  5. washwashed with saturated aqueous NaHCO3 solution (2×250 mL)
  6. dry with materialThe organic layer was dried (K2CO3)
  7. concentrationconcentrated to dryness
  8. washwhile eluting with CHCl3

Sources & evidence

ORD record
ord-7bacae8099d443b2ba16d4de394f5c91
Source dataset
uspto-grants-1993_07
Patent number
US05227383

Reaction notes

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