aString = 'C((H2)(C(H3))) C((H1)(Cl1)) C((C(H3))3)'
aList = aString.split()
for i in range(len(aList)):
    aList[i] = [pyp.nestedExpr().parseString(aList[i][1:]).asList()[0]]
print(aList)
Not finding the strings expected with pyparsing