AbstractN‐Isobutylidenemethylamine reacted with dimethyl methoxymethylenemalonate to afford theN‐alkylation product3aexclusively. Exchanging theN‐substituent of the Schiff's base from methyl tot‐butyl altered the course of the reaction, allowing Michael addition to take place predominantly. The Michael adduct4con reaction with hydrazinoalkanols6a,b, 6c,dand6egave tetrahydropyrazolo[5,1‐b]oxazoles9a,b, tetrahydro‐pyrazolo[5,1‐b][1,3]oxazines9c,dand hexahydropyrazolo[5,1‐b][1,3]oxazepine9