http://www.cerlabs.com/experiments/1053497774X.pdf follow this link to a pdf file this gives the whole information of synthesis of paracetamol from 4-aminophenol and acetic anhydride.
As an anhydride, It can be prepared by dehydrating its acid, i.e. Acetic acid, by strong dessicant such as Tetraphosphorus decaoxide (P4O10) : P4O10 + 12 CH3COOH ----> 4 H3PO4 + 6 (CH3CO)2O