import arcpy, os

ws = r"C:temp"
map_folder = os.path.join(ws, "maps")
pdf_folder = os.path.join(ws, "pdfs")

arcpy.env.workspace = map_folder
arcpy.env.overwriteOutput = True

# generate list of map documents in folder to loop through
map_list = arcpy.ListFiles("*.mxd")

###
def exportAISMap(mxd_path, out_path):
    mxd = arcpy.mapping.MapDocument(mxd_path)
    # arcpy.mapping.ExportToJPEG(mxd, out_path)
    # arcpy.mapping.ExportToPNG(mxd, out_path)
    arcpy.mapping.ExportToPDF(mxd, out_path)
    print "Exported map file: " + str(out_path) + "n"
    # mxd.save()
    del mxd
###

print "Saving out " + str(len(map_list)) + " map documentsn"

for map_file in map_list:
    print map_file

    mxd_path = os.path.join(map_folder, map_file)

    pdf_file = map_file.replace(".mxd", ".pdf")
    pdf_path = os.path.join(pdf_folder, pdf_file)

    exportAISMap(mxd_path, pdf_path)

from multiprocessing import process

exportAISMap(mxd_path, pdf_path)

p = Process(target = exportAISMap, args = (mxd_path, pdf_path))
p.start()
p.join()