The condensation of 2-chlorobenzoyl chloride (I) with cyanacetic acid (II) by means of butyllithium in THF gives 2-(2-chlorobenzoyl)acetonitrile (III), which is cyclized with N-(ethoxycarbonyl)piperidin-4-one (IV) by means of S and morpholine in refluxing methanol yielding the bicyclic ethyl ester (V). The acylation of (V) with bromoacetyl bromide (VI) in chloroform affords the corresponding 2-(bromoacetamido) derivative (VII), which by reaction with dry ammonia in THF is converted into the 2-glycinamido derivative (VIII). The cyclization of (VIII) in refluxing pyridine gives the tricyclic ethyl ester (IX), which by reaction with P2S5 in refluxing pyridine is converted into the corresponding thioketone (X). The reaction of (X) with hydrazine in methanol yields the 2-hydrazino derivative (XI), which is acylated with acetyl chloride (XII) and NaHCO3 in THF affording the 2-(acetylhydrazino) derivative (XIII). The cyclization of (XIII) in refluxing acetic acid gives the tetracyclic ethyl ester (XIV), which is decarboxylated with 30% HBr yielding the tetracyclic precursor (XV). The acylation of (XV) with 2-(3,4-dimethoxyphenylthio)acetic acid (XVI) by means of dicyclohexylcarbodiimide (DCC) in DMF affords the acylated compound (XVII), which is finally treated with P2S5 or Lawesson's reagent.

The condensation of 2-chlorobenzoyl chloride (I) with cyanacetic acid (II) by means of butyllithium in THF gives 2-(2-chlorobenzoyl)acetonitrile (III), which is cyclized with N-(ethoxycarbonyl)piperidin-4-one (IV) by means of S and morpholine in refluxing methanol yielding the bicyclic ethyl ester (V). The acylation of (V) with bromoacetyl bromide (VI) in chloroform affords the corresponding 2-(bromoacetamido) derivative (VII), which by reaction with dry ammonia in THF is converted into the 2-glycinamido derivative (VIII). The cyclization of (VIII) in refluxing pyridine gives the tricyclic ethyl ester (IX), which by reaction with P2S5 in refluxing pyridine is converted into the corresponding thioketone (X). The reaction of (X) with hydrazine in methanol yields the 2-hydrazino derivative (XI), which is acylated with acetyl chloride (XII) and NaHCO3 in THF affording the 2-(acetylhydrazino) derivative (XIII). The cyclization of (XIII) in refluxing acetic acid gives the tetracyclic ethyl ester (XIV), which is decarboxylated with 30% HBr yielding the tetracyclic precursor (XV). The acylation of (XV) with 2-(3,4-dimethoxyphenylthio)acetic acid (XVI) by means of dicyclohexylcarbodiimide (DCC) in DMF affords the acylated compound (XVII), which is finally treated with P2S5 or Lawesson's reagent.