  In this paper we explore the idea of looking at the Dirac quantisation
conditions as $\hbar$-dependent constraints on the tangent bundle to
phase-space. Starting from the path-integral version of classical mechanics and
using the natural Poisson brackets structure present in the cotangent bundle to
the tangent bundle of phase- space, we handle the above constraints using the
standard theory of Dirac for constrained systems. The hope is to obtain, as
total Hamiltonian, the Moyal operator of time-evolution and as Dirac brackets
the Moyal ones. Unfortunately the program fails indicating that something is
missing. We put forward at the end some ideas for future work which may
overcome this failure.
