Efficient One‐Pot Multicomponent Approach to 3‐Phenylpyrrolo[1,2‐a]Pyrazine and Novel 3‐Phenylpyrazino[1,2‐a]Indole in Aqueous Medium

A facile and atom‐efficient route via a new aqueous synthetic protocol for the greener and more efficient preparation of 3‐phenylpyrrolo[1,2‐ a ]pyrazine and 3‐phenylpyrazino[1,2‐ a ]indole by the one‐pot, three‐component method under mild reaction conditions is developed with substituted phenacyl bromides, aqueous ammonium hydroxide, and the corresponding 1 H ‐pyrrole‐2‐carbaldehyde and 1 H ‐indole‐2‐carbaldehyde. A reaction cascade consisting of N‐alkylation, imine formation, and annulation by condensation produces a sequence of three C−N bonds.