Using O=Cc1ccc2c(c1)NC(=O)CS2, [PH3+]C(c1ccccc1)(c1ccccc1)c1ccccc1 to produce C=Cc1ccc2c(c1)NC(=O)CS2, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.