[surayutaka]

Measure 2,5-dimethoxytetrahydrofuran into a flask. Add p-toluenesulfonamide and acetic acid. Heat at reflux for two hours.

Q: What is the function of acetic acid in this synthesis?

I guess its a solvent and acid catalyst? Any take?

[discodermolide]

Measure 2,5-dimethoxytetrahydrofuran into a flask. Add p-toluenesulfonamide and acetic acid. Heat at reflux for two hours.

Q: What is the function of acetic acid in this synthesis?

I guess its a solvent and acid catalyst? Any take?

2,5-dimethoxytetrahydrofuran is effectively an acetal, the acetic acid will cause ring opening allowing the toluenesulfonamide to attack with following ring closure.

[surayutaka]

Thanks. Will the acid be reformed after the reaction in this case?

[surayutaka]

its fine! i got it! its just a standard pyrrole synthesis 

[discodermolide]

its fine! i got it!

Good, no problem!