Reacción #2467976

Ecuación de reacción

methyl 3-[(dimethylamino)diazenyl]-5-phenylthiophene-2-carboxylate

sodium hydroxide

HCl

→

solid

Rendimiento 64.2%

3-[(dimethylamino)diazenyl]-5-phenylthiophene-2-carboxylic acid

Rendimiento 64.2%

Disolventes

methanol

water

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONThe mixture was diluted with ice cold water
2. 2
   workup.STIRRINGThe mixture was stirred for 30 min
3. 3
   Filtraciónthe precipitated solid was filtered
4. 4
   Lavadowashed with water
5. 5
   Otrodried
6. 6
   OtroThe solid was chromatographed over silica gel column
7. 7
   Otroto give the product
8. 8
   OtroThe crude solid was recrystallized from hexane-chloroform

Procedimiento

To a solution of methyl 3-[(dimethylamino)diazenyl]-5-phenylthiophene-2-carboxylate (1.8 g, 6.22 mmol) in methanol (50 mL) was added a solution of sodium hydroxide (1.24 g, 31.1 mmol) in water (15 mL) and stirred at rt for 16 h. The mixture was diluted with ice cold water and acidified with dil. HCl. The mixture was stirred for 30 min and the precipitated solid was filtered, washed with water and dried. The solid was chromatographed over silica gel column using hexane-ethyl acetate (70:30) as eluents to give the product. The crude solid was recrystallized from hexane-chloroform to give the product as a pale pink color solid (1.1 g, 61%), mp 162-166° C. IR (neat)νmax. 2923, 2853, 1708, 1260, 1220, 1173, 1042, 1020, 879, 836 cm−1; 1H NMR (400 MHz, CDCl3): δ 12.15 (1H, br s), 7.58-7.60 (2H, m), 7.44 (1H, s), 7.32-7.40 (3H, m), 3.65 (3H, s), 3.25 (3H, s); 13C NMR (100 MHz, CDCl3): δ 162.8, 153.3, 149.7, 133.3, 129.1, 129.0, 125.9, 120.1, 113.4, 44.3, 37.0; LC-MS (positive ion mode): m/z 298 (M+Na)+.

Fuente