One-pot synthesis of benzisoindolenines used in the preparation of naphthalocyanines
A method of effecting a one-pot conversion of a tetrahydronaphthalic anhydride of formula (I): to a nitrate salt of a benzisoindolenine of formula (II): The method comprises heating the tetrahydronaphthalic anhydride of formula (I) with a reagent mixture comprising ammonium nitrate so as to effecting concomitant dehydrogenation during the conversion.
1. A method of effecting a one-pot conversion of a tetrahydronaphthalic anhydride of formula (I):
to a nitrate salt of a benzisoindolenine of formula (II):
said method comprising heating said tetrahydronaphthalic anhydride of formula (I) with a reagent mixture comprising ammonium nitrate so as to effecting concomitant dehydrogenation during the conversion, 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.
2. The method of claim 1 , wherein R 1 , R 2 , R 3 and are all hydrogen.
3. The method of claim 1 , wherein said reagent mixture comprises at least 2 equivalents of ammonium nitrate with respect to said tetrahydronaphthalic anhydride of formula (I).
4. The method of claim 1 , wherein said reagent mixture comprises urea.
5. The method of claim 1 , wherein said reagent mixture comprises at least one further ammonium salt.
6. The method of claim 5 , wherein said at least one further ammonium salt is selected from the group consisting of: ammonium sulfate and ammonium benzenesulfonate.
7. The method of claim 1 , wherein said reagent mixture comprises ammonium molybdate.
8. The method of claim 1 , wherein said heating is within a temperature range of 150 to 200° C.
9. The method of claim 8 , wherein said heating is in the presence of a solvent selected from the group consisting of: nitrobenzene, diphenyl, diphenyl ether, mesitylene, anisole, phenetole, dichlorobenzene, trichlorobenzene and mixtures thereof.
10. The method of claim 1 , further comprising the step of:
liberating the benzisoindolenine of formula (II) from the benzisoindolenine nitrate salt using sodium methoxide.
11. The method of claim 10 , further comprising the step of:
macrocyclizing said benzisoindolenine to form a naphthalocyanine of formula (III):
wherein:
M is absent or selected from Si(A 1 )(A 2 ), Ge(A 1 )(A 2 ), Ga(A 1 ), Mg, Al(A 1 ), TiO, Ti(A 1 )(A 2 ), ZrO, Zr(A 1 )(A 2 ), VO, V(A 1 )(A 2 ), Mn, Mn(A 1 ), Fe, Fe(A 1 ), Co, Ni, Cu, Zn, Sn, Sn(A 1 )(A 2 ), Pb, Pb(A 1 )(A 2 ), Pd and Pt;
A 1 and A 2 are axial ligands, which may be the same or different, and are selected from —OH, halogen or —OR q ;
R q is selected from C 1-16 alkyl, C 5-20 aryl, C 5-20 arylalkyl, C 1-20 alkylcarbonyl, C 1-20 alkoxycarbonyl or Si(R x )(R y )(R z ); and
R x , R y and R z may be the same or different and are selected from C 1-20 alkyl, C 5-20 aryl, C 5-20 arylalkyl, C 1-20 alkoxy, C 5-20 aryloxy or C 5-20 arylalkoxy.
12. The method of claim 11 , wherein M is Ga(A 1 ).
13. The method of claim 11 , wherein macrocyclizing step comprises heating said benzisoindolenine of formula (II) in the presence of GaCl 3 .