IAtomContainer newContainer, IAtomContainer oldcontainer) {
IChemModel chemModel = controllerhub.getChemModel();
IReaction reaction = ReactionSetManipulator.getReactionByReactionID(chemModel.getReactionSet(), reactionId);
IAtomContainer mol=newContainer.getBuilder().newInstance(IAtomContainer.class,newContainer);
mol.setID(newContainer.getID());
reaction.addReactant(mol);
chemModel.getMoleculeSet().removeAtomContainer(oldcontainer);
if(chemModel.getMoleculeSet().getAtomContainerCount()==0)
chemModel.getMoleculeSet().addAtomContainer(chemModel.getBuilder().newInstance(IAtomContainer.class));
if(controllerhub.getUndoRedoFactory()!=null && controllerhub.getUndoRedoHandler()!=null){
IUndoRedoable undoredo = controllerhub.getUndoRedoFactory().getMakeReactantOrProductInExistingReactionEdit(chemModel, newContainer, oldcontainer, reactionId, true, "Make Reactant in "+reactionId);