N,N-Diethylaniline → 4-chloroimidazo[1,2-a]quinoxaline

HRID 389078Notes

Reaction equation

HRID 389078 reaction equation
[CH:1]1[N:5]2[C:6]3[C:11]([NH:12][C:13](=O)[C:4]2=[N:3][CH:2]=1)=[CH:10][CH:9]=[CH:8][CH:7]=3.C(N(CC)C1C=CC=CC=1)C.C(Cl)[Cl:27].CO>P(Cl)(Cl)(Cl)=O>[Cl:27][C:13]1[C:4]2[N:5]([CH:1]=[CH:2][N:3]=2)[C:6]2[C:11]([N:12]=1)=[CH:10][CH:9]=[CH:8][CH:7]=2

Participants

5

Reactant 3

HCID 7061N,N-DiethylanilineHCID 15667665Imidazo[1,2-a]quinoxalin-4(5H)-oneHCID 21226129Dichloromethane methanol

Product 1

HCID 107745254-chloroimidazo[1,2-a]quinoxalineYield 75%

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent2×

Procedure

Compound 11 (1.4 g, 6.4 mmol) is solubilized in phosphorus oxychloride (24 ml), and N,N-diethylaniline (3.6 ml). The reaction mixture obtained is carried to reflux for approximately 2 h. The product is insoluble in POCl3 even after heating. The reaction is monitored by TLC, eluent: CH2Cl2/MeOH (95/5). TLC shows the presence of the end product, but also the appearance of breakdown products. The reaction mixture is dark brown in colour. The POCl3 is evaporated under vacuum. The residue is cooled in an ice bath before adding a little water and, dropwise, a saturated sodium bicarbonate solution to neutralize POCl3. A light yellow foam and a brown precipitate appear. The solid is isolated by filtration and is recrystallized in methanol. A beige solid (0.97 g, 75%) is obtained; 1H NMR (300 MHz, DMSO-d6) δ: 8.5 (s, 1H, N—CH—C), 8.06 (d, 1H, ArH), 7.56 (s, 1H, C—CH—N), 7.35 (m, 1H, ArH), 7.25 (m, 2H, ArH). Analysis calculated for C10H6N3C1: C, 58.98; H, 2.97; N, 20.64. Experimental: C, 59.12; H, 2.76; N, 20.45.

Workup

  1. customThe reaction mixture obtained
  2. temperatureto reflux for approximately 2 h
  3. temperatureafter heating
  4. customThe POCl3 is evaporated under vacuum
  5. temperatureThe residue is cooled in an ice bath
  6. additionbefore adding a little water
  7. customThe solid is isolated by filtration
  8. customis recrystallized in methanol

Sources & evidence

ORD record
ord-868b9243070e4501ab42b4d893cf4864
Source dataset
uspto-grants-2013_02
Patent number
US08378098B2

Reaction notes

Loading…