ChemicalBook CAS DataBase List Vardenafil IMpurity 2

Vardenafil IMpurity 2 synthesis

5synthesis methods

Product Name:Vardenafil IMpurity 2
CAS Number:1417529-69-1
Molecular formula:C23H30N6O6S
Molecular Weight:518.59

5308-25-8 Synthesis

5308-25-8
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Imidazo[5,1-f][1,2,4]triazine-7-carboxylic acid, 2-[5-(chlorosulfonyl)-2-ethoxyphenyl]-1,4-dihydro-5-methyl-4-oxo-, ethyl ester

1417529-68-0
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1417529-69-1
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Yield:1417529-69-1 62%

Reaction Conditions:

in tetrahydrofuran at 0 - 20; for 18 h;

Steps:

8 4.8. 2-[(2-Ethoxy-5(4-ethylpiperazine-1-sulphonyl)phenyl)]-7-ethoxycarbonyl-5-methyl-imidazo[5,1-f][1,2,4]triazin-4(3H)-one 15e

2-(2-Ethoxyphenyl)-7-ethyl-5-methyl-imidazo[5,1-f][1,2,4]triazin- 4(3H)-one 14e (200 mg, 5.84 10 4 mol) was slowly added to chlorosulfonic acid (0.5 mL, 874.5 mg; 7.5 10 4 mol). The reaction mixturewas stirred for 1.5 h at room temperature. The product was poured into ice-water (5 mL) and extracted with dichloromethane (3 15 mL). The chloroformextracts were combined, dried (MgSO4), filtered, and the solvent was evaporated to give a benzenesulfonyl chloride (234 mg, 92%) as white powder; Rf (EtOAc/EtOH 3:1) 0.34; Rf (EtOAc) 0.7. Benzenesulfonyl chloride (234 mg, 5.32 10 4 mol) was dissolved in THF (3 mL) and cooled to 0 C. N-Ethylpiperazine (133.7 mg, 0.15 mL; 1.17 10 3 mol) was added to this solution. The reaction mixture was stirred at room temperature for 18 h. The solvent was evaporated in vacuo and the residue was dissolved in dichloromethane (5 mL). The organic solution was washed twice withwater, dried (MgSO4), filtered, and the solventwas evaporated. The residue was purified by column chromatography on silica gel (hexane/EtOAc, 1:1 v/v) afforded the product as a light yellow solid, which was crystallized from absolute ethanol to give 170 mg (62%), mp 215e7 C; [found: C, 53.45; H, 5.85; N, 16.25; S, 6.20. C23H30N6O6S requires C, 53.27; H, 5.83; N, 16.21; S, 6.18%]; Rf (EtOAc/EtOH, 6:1) 0.23; Rf (EtOAc) 0.1. nmax (crystal): 3289, 2981, 2935, 1710, 1614, 1590 cm 1. 1H NMR (CDCl3, d ppm): 10.18 (br s, 1H, NH/O), 8.69 (d, J 2.4 Hz, 1H, 6-H of C6H4), 7.92 (dd, J 2.4 and 8.8 Hz, 1H, 4-H of C6H4), 7.20 (d, J 8.8 Hz, 1H, 3-H of C6H4), 4.54 (q, J 7.2 Hz, 2H, CH2O), 4.40 (q, J 7 Hz, 2H, CH2O), 3.21 (br s, 4H, 2 CH2N), 2.73 (s, 3H, CH3C), 2.67 (br s, 4H, 2 CH2N), 2.53 (br s, 2H, NCH2CH3), 1.64 (t, J 6.8 Hz, 3H, CH3), 1.52 (t, J 7.1 Hz, 3H, CH3), 1.12 (br s, 3H, NCH2CH3). 13C NMR: (CDCl3, d ppm): 157.5, 157.5, 154.4, 148.4, 141.2, 134.0, 132.8, 130.8, 128.5, 117.8, 116.7, 113.2, 65.7, 62.2, 54.2, 48.4, 45.8, 14.9, 14.6, 13.3. MS (ESI, matrix CCA): [MtH]t found 519.3. C23H30N6O6S requires 518.20.

References:

Olszewska, Teresa;Gajewska, Ewa P.;Milewska, Maria J. [Tetrahedron,2013,vol. 69,# 2,p. 474 - 480]