2-Methyl-4,5-dihydroimidazole as a doubly nucleophilic unit: preparation of dihydroimidazole azaprostanoids

2-Methyl-4,5-dihydroimidazole is incorporated as a doubly nucleophilic synthon, by successive alkylations at N-1 and C-2(Me), into monocyclic 9,12- and 8,11-diazaprostanoids containing the dihydroimidazole moiety. 2-Methyl-3a,4,7,7a-tetrahydrobenzimidazole is prepared (from 1,2,3,6-tetrahydrophthalic anhydride) and elaborated in the same way into a diazaprostacyclin precursor.