Patent ID: 7825262

Claim:
A method of effecting a one-pot conversion of a tetrahydronaphthalic anhydride of formula (I): to a salt of a benzisoindolenine of formula (II): said method comprising heating said tetrahydronaphthalic anhydride of formula (I) with a reagent mixture comprising ammonium nitrate, wherein: R 1 , R 2 , R 3 and R 4 are each independently selected from hydrogen, hydroxyl, C 1-20 alkyl, C 1-20 alkoxy, amino, C 1-20 alkylamino, di(C 1-20 alkyl)amino, halogen, cyano, thiol, C 1-20 alkylthio, nitro, C 1-20 alkylcarboxy, C 1-20 alkylcarbonyl, C 1-20 alkoxycarbonyl, C 1-20 alkylcarbonyloxy, C 1-20 alkylcarbonylamino, C 5-20 aryl, C 5-20 arylalkyl, C 5-20 aryloxy, C 5-20 arylalkoxy, C 5-20 heteroaryl, C 5-20 heteroaryloxy, C 5-20 heteroarylalkoxy or C 5-20 heteroarylalkyl.