Diisopropyl Ether → Pyrano(2,3-g)indole-2-carboxylic acid, 1,7,8,9-tetrahydro-

HRID 1374809Notes

Reaction equation

HRID 1374809 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[C:7]3[O:13][CH2:12][CH2:11][CH2:10][C:8]3=2)[CH:3]=[C:2]1[C:14]([O:16]C)=[O:15].[O:18]1[C:30]2[C:22]([CH2:23][C:24]3[CH2:25][CH2:26][NH:27][C:28]=3[CH:29]=2)=[CH:21][CH:20]=[C:19]1[C:31]([O:33]C)=[O:32].[O:35]1[C:40]2[C:41]3[CH:42]=[CH:43][NH:44][C:45]=3[CH2:46][CH2:47][C:39]=2[CH:38]=[CH:37][CH:36]1[C:48]([O:50]C)=[O:49].C(OC(C)C)(C)C.C(OC(C)C)(C)C.CCCCCCC>>[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[C:7]3[O:13][CH2:12][CH2:11][CH2:10][C:8]3=2)[CH:3]=[C:2]1[C:14]([OH:16])=[O:15].[O:18]1[C:30]2[C:22]([CH2:23][C:24]3[CH2:25][CH2:26][NH:27][C:28]=3[CH:29]=2)=[CH:21][CH:20]=[C:19]1[C:31]([OH:33])=[O:32].[O:35]1[C:40]2[C:41]3[CH:42]=[CH:43][NH:44][C:45]=3[CH2:46][CH2:47][C:39]=2[CH:38]=[CH:37][CH:36]1[C:48]([OH:50])=[O:49]

Participants

8

Reactant 5

HCID 7914Diisopropyl EtherHCID 12831970Methyl 7,8-dihydro-9h-pyrano[2,3-g]indol-2-carboxylateHCID 22282688HCID 22282688, compoundHCID 22997467HCID 22997467, compoundHCID 86600348HCID 86600348, compound

Product 3

HCID 3067316Pyrano(2,3-g)indole-2-carboxylic acid, 1,7,8,9-tetrahydro-HCID 222827195,6-dihydro-7H-pyrano[2,3-e]indole-2-carboxylic acidHCID 866003476,7-dihydro-5H-pyrano[3,2-f]indole-2 carboxylic acid

Procedure

7,8-Dihydro-9H-pyrano[2,3-g]indole-2-carboxylic acid, 6,7-dihydro-5H-pyrano[3,2-f]indole-2-carboxylic acid and 5,6-dihydro-7H-pyrano[2,3-e]indole-2-carboxylic acid were prepared according to the method described in Example 3, using a mixture (10:5:2) of methyl 7,8-dihydro-9H-pyrano[2,3-g]indole -2-carboxylate, methyl 6,7-dihydro-5H-pyrano[3,2-f]indole -2-carboxylate and methyl 5,6-dihydro-7H-pyrano[2,3-e]indole -2-carboxylate (4.33 g, 18.7 mmol) to produce, after trituration with isopropyl ether, a mixture [(2,3-g):(3,2-f):(2,3-e)—7:1:2] of products (2.30 g, 57%) as a white solid. The filtrate was evaporated and purified by flash column chromatography [SiO2; ethyl acetate-heptane (2:1)+0.5% acetic acid] to afford an oil which solidified upon treatment with isopropyl ether-heptane to afford a mixture [(2,3-g):(3,2-f):(2,3-e)—44:22:34] of products (818 mg, 20%) as a white solid. The products were combined and used without further purification.

Workup

  1. customto produce
  2. customThe filtrate was evaporated
  3. custompurified by flash column chromatography [SiO2; ethyl acetate-heptane (2:1)+0.5% acetic acid]
  4. customto afford an oil which

Sources & evidence

ORD record
ord-e707c482b52b415e8a0585fc6acfad06
Source dataset
uspto-grants-2007_01
Patent number
US07166613B2

Reaction notes

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