Preparation of the intermediates will be shown in the examples below.Compounds of the present invention wherein R is other than hydrogen are conveniently prepared by treating the corresponding heterocycle where R is hydrogen with an appropriate acylating agent such as an acyl halide, e.g., undecanoyl chloride,pivaloyl chloride, benzoylchloride, p-methoxybenzoyl chloride or an ahydride, e.g. acetic