Convert PDF to Doc with Google Script Editor

I'm looking to convert PDF to google Doc in Drive using Google Script Editor. However keep getting error message "Converting from application/pdf to application/doc is not supported". Is this conversion possible in script? My attempt as below, would be great to hear any advice.

function convertdPDF2doc() {
  var pdffile = DriveApp.getFileById();
  var pdfblob = pdffile.getAs('application/doc');

  pdfblob.setName(doc.getName() + ".doc");
  DriveApp.createFile(docblob);

}

function pdfToDoc() {  
  var fileBlob = DriveApp.getFileById('0B3m2D6239t6aWHo5TVpyYzhxV1U').getBlob();  
  var resource = {
    title: fileBlob.getName(),
    mimeType: fileBlob.getContentType()
  };
  var options = {
    ocr: true
  };
  var docFile = Drive.Files.insert(resource, fileBlob, options);  
  Logger.log(docFile.alternateLink);  
}

Add Drive API to google apps script project https://developers.google.com/apps-script/guides/services/advanced#enabling_advanced_services

You can see you pdf file id on google drive when you download it http://i.imgur.com/3pYvwjx.png