Hexamethyldisilazane → 4-(Cyclopentylamino)-1-methylimidazo(1,2-a)quinoxaline

HRID 1954709

Reaction equation

HRID 1954709 reaction equation
[CH3:1][C:2]1[N:6]2[C:7]3[C:12]([NH:13][C:14](=O)[C:5]2=[N:4][CH:3]=1)=[CH:11][CH:10]=[CH:9][CH:8]=3.C[Si](C)(C)N[Si](C)(C)C.S([O-])([O-])(=O)=O.[NH4+].[NH4+].[CH:32]1([NH:37]C2CCCC2)[CH2:36][CH2:35][CH2:34][CH2:33]1>>[CH:32]1([NH:37][C:14]2[C:5]3[N:6]([C:2]([CH3:1])=[CH:3][N:4]=3)[C:7]3[C:12]([N:13]=2)=[CH:11][CH:10]=[CH:9][CH:8]=3)[CH2:36][CH2:35][CH2:34][CH2:33]1

Participants

5

Reactant 4

HCID 13838HexamethyldisilazaneHCID 247671DicyclopentylamineHCID 6097028Ammonium SulfateHCID 107743711-methylimidazo[1,2-a]quinoxaline-4(5H)-one

Product 1

HCID 101992194-(Cyclopentylamino)-1-methylimidazo(1,2-a)quinoxaline

Conditions

Temperature
120 °C

Procedure

A mixture of 3.5 g of 1-methylimidazo[1,2-a] quinoxalin-4(5H)-one (example 2), 13 ml of hexamethyl disilazane, 0.5 g of ammonium sulphate and 8.7 ml dicyclopentylamine is stirred at 120° C. in a Dean-Stark apparatus for 24 h. After concentrating the resulting mixture under vacuum, the residue is added with water and extracted with ethyl acetate. The organic extracts are then washed with water and saturated NaCl, dried and evaporated, thereby obtaining 1.5 g of a raw product that is subsequently chromatographed on SiO2 (eluent: CH2Cl2 /AcOEt 97:3). By recrystallizing from ethyl acetate, there is obtained 4-cyclopentylamino-1-methyl imidazo [1,2-a]quinoxaline. m.p. (DSC)=167.3° C. (onset); IR (KBr): 3294, 2948, 1544 cm-1 ; 1H-NMR (CDCl3): δ8.0 (1H,dd), 7.4÷7.05 (3H,m), 6.0 (1H,d), 4.6 (1H,m), 2.8 (3H,s), 2.3÷2.05 (4H,m), 2.0÷1.4 (4H,m); UV (EtOH): λmax =225, 243, 272 301, 316, 329 nm. Elementary analysis for C16H16N4 (m.w. 266.35): calcd. C 72.15, H 6.81, N 21.03%; found C 71.86, H 6.81, N 20.79%.

Workup

  1. concentrationAfter concentrating the resulting mixture under vacuum
  2. additionthe residue is added with water
  3. extractionextracted with ethyl acetate
  4. washThe organic extracts are then washed with water and saturated NaCl
  5. customdried
  6. customevaporated
  7. customobtaining 1.5 g of a raw product that
  8. customis subsequently chromatographed on SiO2 (eluent: CH2Cl2 /AcOEt 97:3)
  9. customBy recrystallizing from ethyl acetate

Sources & evidence

ORD record
ord-ffa357996fad4e948f4665cdf83da773
Source dataset
uspto-grants-2000_09
Patent number
US06124287

Linked notes

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