Pentane → 1,1'-diBOC-2,10-dicarbethoxy-6-ethoxycarbonyloxy-indolo[2,3-b]carbazole

HRID 33734Notes

Reaction equation

HRID 33734 reaction equation
[C:1]([C:6]1[CH:7]=[C:8]2[C:16](=[CH:17][CH:18]=1)[NH:15][C:14]1[C:13]([O:19][C:20]([O:22][CH2:23][CH3:24])=[O:21])=[C:12]3[NH:25][C:26]4[CH:27]=[CH:28][C:29]([C:32]([O:34][CH2:35][CH3:36])=[O:33])=[CH:30][C:31]=4[C:11]3=[CH:10][C:9]2=1)([O:3][CH2:4][CH3:5])=[O:2].[Li][C:38]([CH3:41])([CH3:40])[CH3:39].CCCCC.BrC1C=C2C(=CC=1)N([C:61]([O:63][C:64]([CH3:67])([CH3:66])[CH3:65])=[O:62])C1C(OC(OCC)=O)=C3N(C(OC(C)(C)C)=O)C4C=CC(Br)=CC=4C3=CC2=1.Cl[C:90]([O:92]CC)=[O:91].[NH4+].[Cl-]>C1COCC1.CCOC(C)=O.CCCCCC>[C:90]([C:30]1[C:29]([C:32]([O:34][CH2:35][CH3:36])=[O:33])=[CH:28][CH:27]=[C:26]2[C:31]=1[C:11]1[C:12](=[N:25]2)[C:13]([O:19][C:20]([O:22][CH2:23][CH3:24])=[O:21])=[C:14]2[N:15]=[C:16]3[C:8]([CH:7]=[C:6]([C:1]([O:3][CH:4]([C:61]([O:63][C:64]([CH3:67])([CH3:66])[CH3:65])=[O:62])[CH3:5])=[O:2])[CH:18]=[CH:17]3)=[C:9]2[CH:10]=1)([O:92][C:38]([CH3:41])([CH3:40])[CH3:39])=[O:91]

Participants

9

Reactant 6

HCID 8003PentaneHCID 10928Ethyl chloroformateHCID 25517Ammonium ChlorideHCID 115693742,10-Dicarbethoxy-6-ethoxycarbonyloxy-5,7-dihydro-indolo[2,3-b]carbazoleHCID 167494182,10-Dibromo-6-ethoxycarbonyloxy-5,7-diBOC-indolo[2,3-b]carbazoleHCID 178418306HCID 178418306, compound

Product 1

HCID 865912841,1'-diBOC-2,10-dicarbethoxy-6-ethoxycarbonyloxy-indolo[2,3-b]carbazoleYield 89%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 21226206Ethyl acetate hexaneSolvent

Conditions

Temperature
-10 °C

Procedure

2,10-Dicarbethoxy-6-ethoxycarbonyloxy-5,7-dihydro-indolo [2,3-b]carbazole (63). To a solution of 1.7 M t-BuLi in pentane (32.3 mL, 54.8 mmol) in THF (200 mL) at −100° C. under argon was added 61 (7.0 g, 9.97 mmol) in THF (20 mL), and stirred for 10 min. ClCO2CH2CH3 (30 mL) was added and the mixture was slowly warmed to −10° C. during 2.5 h. The reaction mixture was poured into saturated aqueous NH4Cl and extracted with 50% EtOAc/hexane. The combined organic extracts were dried (MgSO4), filtered, and concentrated to afford a crude product. Flash chromatography (10%; 20% EtOAc/hexane) yielded 1,1′-diBOC-2,10-dicarbethoxy-6-ethoxycarbonyloxy-indolo[2,3-b]carbazole 62 as a white solid (6.1 g, 89%). 62 (4.3 g, 6.24 mmol) was deprotected using the general procedure. Recrystallization (ethyl acetate/hexane) afforded 63 as a white solid (2.8 g, 92%): 1H NMR (300 MHz, CDCl3) δ 1.50 (m, 9, CO2CH2CH3), 4.48 (m, 6, CO2CH2CH3), 7.46 (d, J=8.3 Hz, 2, ArH), 8.16 (dd, J=1.5, 8.3 Hz, 2, ArH), 8.49 (br.s, 2, NH), 8.71 (s, 1, ArH), 8.89 (d, J=1.5 Hz, 2, ArH).

Workup

  1. extractionextracted with 50% EtOAc/hexane
  2. dry with materialThe combined organic extracts were dried (MgSO4)
  3. filtrationfiltered
  4. concentrationconcentrated
  5. customto afford a crude product

Sources & evidence

ORD record
ord-3c8301ab02824f52a60b235ab89881b7
Source dataset
uspto-grants-2008_09
Patent number
US07429610B2

Reaction notes

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