Isopropanol → 6-ethyl-9-oxo-9H-indeno[1,2-b]pyrazine-2,3-dicarbonitrile

HRID 240316

Reaction equation

[CH2:1]([C:3]1[CH:11]=[C:10]2[C:6]([CH2:7][C:8](=O)[C:9]2=O)=[CH:5][CH:4]=1)[CH3:2].[NH2:14]/[C:15](/[C:20]#[N:21])=[C:16](\[NH2:19])/[C:17]#[N:18].CC([OH:25])C>>[CH2:1]([C:3]1[CH:4]=[CH:5][C:6]2[C:7](=[O:25])[C:8]3[C:9]([C:10]=2[CH:11]=1)=[N:14][C:15]([C:20]#[N:21])=[C:16]([C:17]#[N:18])[N:19]=3)[CH3:2]

Participants

Reactant 3

HCID 3776Isopropanol

HCID 2723951Diaminomaleonitrile

HCID 57831019HCID 57831019, compound

Product 1

HCID 578310246-ethyl-9-oxo-9H-indeno[1,2-b]pyrazine-2,3-dicarbonitrile

Conditions

Temperature: 80 °C

Procedure

A suspension of 29c (298 mg, 1.71 mmol) and diaminomaleonitrile (185 mg, 1.71 mmol) in iPrOH (17 ml) was stirred at 80° C. for 20 h. The solvent was evaporated under reduced pressure and the crude was purified by flash chromatography (CH2Cl2). The obtained product was purified by preparative HPLC, obtaining 32 as yellow solid as 7:3 regioisomeric mixture with the 7-ethyl analogue. 1H NMR (300 MHz, CDCl3): main product: δ 7.95 (d, 1H), 7.80 (m, 1H), 7.67 (bd, 1H), 2.83 (q, 2H), 1.33 (t, 3H); minority product: δ 7.89 (d, 1H), 7.89 (m, 1H), 7.56 (bd, 1H), 2.86 (q, 2H), 1.36 (t, 3H). ESI+MS: calcd for C15H8N4O: 260.26; found: 261.1 (MH+).

Workup

customThe solvent was evaporated under reduced pressure
customthe crude was purified by flash chromatography (CH2Cl2)
customThe obtained product was purified by preparative HPLC

Sources & evidence

ORD record: ord-2ecba929284b42688b3bc34e18d072dc
Source dataset: uspto-grants-2014_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08648076B2

Linked notes

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