Phosphorus oxychloride → HCID 69661784, compound
Reaction equation
[CH3:1][C:2]1[CH:3]=[C:4](O)[C:5]2[N:13]3[C:8]([C:9]([C:14]4[C:19]([CH3:20])=[CH:18][C:17]([CH3:21])=[CH:16][C:15]=4[CH3:22])=[CH:10][CH:11]=[CH:12]3)=[CH:7][C:6]=2[N:23]=1.OC1C2N3C(C=CC=C3)=C(C3C(C)=CC(C)=CC=3C)C=2N=C(C)C=1.P(Cl)(Cl)([Cl:51])=O>>[Cl:51][C:4]1[C:5]2[N:13]3[C:8]([C:9]([C:14]4[C:19]([CH3:20])=[CH:18][C:17]([CH3:21])=[CH:16][C:15]=4[CH3:22])=[CH:10][CH:11]=[CH:12]3)=[CH:7][C:6]=2[N:23]=[C:2]([CH3:1])[CH:3]=1Participants
3
Procedure
Heat at 100° C. for 1 h a solution of 4-hydroxy-2-methyl-10-(2,4,6-trimethylphenyl)pyridino-[2,3-b]indolizine 2-methyl-9-(2,4,6-trimethylphenyl)pyrido[2,3-b]-indolizin-4-ol (10.1 g; 32 mmol) in phosphorus oxychloride (60 mL), cool to ambient temperature, and concentrate in vacuo. Partition the residue into ice water and CH2Cl2. Separate the aqueous phase, extract twice with CH2Cl2, and wash the combined organic extracts with a 1 N aqueous sodium hydroxide solution and then with water. Dry the solution over Na2SO4, filter, and concentrate in vacuo. Filter the dark residue through a short pad of silica gel and wash with 25% EtOAc in hexane. Concentrate the filtrate in vacuo to obtain the title compound as a yellow solid: 1H NMR (400 MHz, CDCl3) δ 2.00 (s, 6H), 2.37 (s, 3H), 2.64 (s, 3H), 6.58 (t, 1H), 6.95 (dd, 1H), 7.00 (s, 2H), 7.07 (s, 1H), 7.08 (d, 1H), 9.26 (d, 1H).