反応 #2467976

反応方程式

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

sodium hydroxide

HCl

→

solid

収率 64.2%

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

収率 64.2%

溶媒

methanol

water

反応条件

後処理

1. 1
   workup.ADDITIONThe mixture was diluted with ice cold water
2. 2
   workup.STIRRINGThe mixture was stirred for 30 min
3. 3
   ろ過the precipitated solid was filtered
4. 4
   洗浄washed with water
5. 5
   その他dried
6. 6
   その他The solid was chromatographed over silica gel column
7. 7
   その他to give the product
8. 8
   その他The crude solid was recrystallized from hexane-chloroform

実験手順

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)+.

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