Method of preparing sultines
A method of preparing a sultine of formula (V) from a dihalogeno compound of formula (IV) is provided. The method comprises reacting the dihalogeno compound (IV) with a hydroxymethanesulfinate salt in a DMSO solvent, 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 arylalkoxy, C 5-20 heteroaryl, C 5-20 heteroaryloxy, C 5-20 heteroarylalkoxy or C 5-20 heteroarylalkyl; and X is Cl, Br or I.
1. A method of preparing a sultine of formula (V) from a dihalogeno compound of formula (IV)
said method comprising the steps of:
reacting said dihalogeno compound (IV) with a hydroxymethanesulfinate salt in a DMSO solvent so as to prepare said sultine (V); and
reacting said sultine (V) with maleic anhydride at elevated temperature to generate tetrahydronaphthalic anhydride as a Diels-Alder adduct,
wherein:
R 1 , R 2 , R 3 and R 4 are each independently selected from the group consisting of: 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 and C 5-20 heteroarylalkyl; and
X is selected from the group consisting of: Cl, Br and I.
2. The method of claim 1 , wherein X is Cl or Br, and NaI is present.
3. The method of claim 1 , wherein a metal carbonate base is present.
4. The method of claim 1 , wherein said hydroxymethanesulfinate salt is sodium hydroxymethanesulfinate.
5. The method of claim 1 , wherein R 1 , R 2 , R 3 and R 4 are all hydrogen.
6. The method of claim 1 , wherein said preparation is performed on a scale of at least 0.3 moles of the dihalogeno compound (IV).
7. The method of claim 1 , wherein said temperature is in the range of 50 to 100° C.
8. The method of claim 1 , wherein said tetrahydronaphthalic anhydride is used as a precursor for naphthalocyanine synthesis.
9. The method of claim 8 , wherein said naphthalocyanine synthesis proceeds via conversion of said tetrahydronaphthalic anhydride to a benzisoindolenine.