The reaction of 2-amino-3'-chlorobenzophenone (I) with dichloroacetyl chloride (II) in acetone gives o-(m'-chlorobenzoyl)-2,2-dichloroacetanilide (III), which is cyclized with potassium cyanide in water yielding 2-amino-3-(m-chlorophenyl-3H-indol-3-ol (IV). Finally, this compound is condensed with 1,3-dibromopropane (A) in refluxing ethanol.

The reduction of 2'-oxospiro-(1,3-dioxolane-2,3'-indoline)-1'-propionitrile (V) with H2 over Raney-Ni in NH3 saturated ethanol gives 2'-oxospiro-(1,3-dioxolane-2,3'-indoline)-1'-propanamine (VI), which, without isolation, is cyclized in refluxing xylene yielding 3',4'-dihydrospiro[1,3-dioxolane-2,10'(2H,10H)pyrimido-[1,2-a]indole] (VII). The hydrolysis of (VII) with aqueous HCl at 85 C affords 3,4-dihydropyrimido[1,2-a]indole-10(2H)-one (VIII), which is finally treated with m-chlorophenylmagnesium bromide (IX) in refluxing ethyl ether.

The reaction of 2-amino-3'-chlorobenzophenone (I) with dichloroacetyl chloride (II) in acetone gives o-(m'-chlorobenzoyl)-2,2-dichloroacetanilide (III), which is cyclized with potassium cyanide in water yielding 2-amino-3-(m-chlorophenyl-3H-indol-3-ol (IV). Finally, this compound is condensed with 1,3-dibromopropane (A) in refluxing ethanol.

The reduction of 2'-oxospiro-(1,3-dioxolane-2,3'-indoline)-1'-propionitrile (V) with H2 over Raney-Ni in NH3 saturated ethanol gives 2'-oxospiro-(1,3-dioxolane-2,3'-indoline)-1'-propanamine (VI), which, without isolation, is cyclized in refluxing xylene yielding 3',4'-dihydrospiro[1,3-dioxolane-2,10'(2H,10H)pyrimido-[1,2-a]indole] (VII). The hydrolysis of (VII) with aqueous HCl at 85 C affords 3,4-dihydropyrimido[1,2-a]indole-10(2H)-one (VIII), which is finally treated with m-chlorophenylmagnesium bromide (IX) in refluxing ethyl ether.