تفاعل #10321

معادلة التفاعل

1-(2-thienylthio)acetone

→

3-methylthieno[2,3-b]thiophene

المردود 42.0%

المذيبات

chlorobenzene

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةThe reaction was heated
2. 2
   درجة الحرارةto reflux overnight
3. 3
   أخرىThe chlorobenzene layer was decanted off
4. 4
   workup.ADDITIONfurther chlorobenzene (15 mL x2) was added to the polyphosphoric acid residue
5. 5
   درجة الحرارةat reflux for 30 minutes
6. 6
   تركيزThe combined chlorobenzene extracts were concentrated in vacuo
7. 7
   أخرىpurified by flash column chromatography on silica
8. 8
   غسيلeluting with 40% dichloromethane/isohexane

الإجراء التجريبي

A 1M solution of 1-(2-thienylthio)acetone (2.6 g, 15.1 mmol) in chlorobenzene (15 mL) was heated to 110° C. under nitrogen and hot polyphosphoric acid (3 mL) was added. The reaction was heated to reflux overnight. The chlorobenzene layer was decanted off and further chlorobenzene (15 mL x2) was added to the polyphosphoric acid residue and stirred at reflux for 30 minutes. The combined chlorobenzene extracts were concentrated in vacuo and purified by flash column chromatography on silica, eluting with 40% dichloromethane/isohexane, to give 3-methylthieno[2,3-b]thiophene (0.97 g, 42%). 1H NMR (500 MHz, CDCl3) δ 7.34 (1H, dd, J=1.0, 5.2 Hz), 7.16 (1H, d, J=5.2 Hz), 6.94 (1H, t, J=1.1 Hz), 2.40 (3H, d, J=1.1 Hz).

المصدر