Process for preparing cross-bridged tetraaza macrocycles
AssigneeThe Procter & Gamble Company
InventorsGeorge Douglas Hiler, II, Christopher Mark Perkins
Life of this patent
Estimating the term…
Abstract
The present invention relates to a process for preparing a cross-bridged tetraaza macrocyclic ligands having formula (I), wherein each R is independently C1-C22 linear alkyl, C1-C22 branched alkyl, C7-C22 alkylenearyl, C8-C22 alkyl substituted alkylenearyl, and mixtures thereof; each index n is independently from 0 to 3, by contacting the a di-quaternary cis tetracycle precursor with as little as one equivalent of a borohydride reducing agent. The present process eliminates the need to use up to a twenty fold excess of reducing agent thereby further eliminating the need for work-up conditions which liberate significant amounts of hydrogen gas and which requires the disposal of large amounts of boron waste products.
Claims14
A process for preparing a tetraaza macrocyclic ligand having the formula:
- wherein each R is independently C1-C22 linear alkyl, C1-C22 branched alkyl, C7-C22 alkylenearyl, C8-C22 alkyl substituted alkylenearyl, and mixtures thereof;
- each index n is independently from 0 to 3, said process comprising the steps of:
- a) reacting one mole equivalent of a tetraaza macrocyclic ligand precursor having the formula:
- wherein X− is an anion which provides charge neutrality, with from 1 mole equivalent to 3 mole equivalents a reducing agent having the formula MBH4 wherein M is selected from the group consisting of lithium, sodium, potassium, and mixtures thereof;
- at a pH of at least 11 to form a macrocyclic ligand;
- and
- b) optionally isolating said macrocyclic ligand.
A process for preparing a tetraaza macrocyclic ligand having the formula:
- wherein R is C1-C22 linear alkyl, C1-C22 branched alkyl, C7-C22 alkylenearyl, C8-C22 alkyl substituted alkylenearyl, and mixtures thereof;
- each index n is independently from 0 to 3, said process comprising the steps of:
- a) combining in a reaction vessel a one molar solution of base and a solvent, wherein the ratio of said base to said solvent is from 1:10 to 1:1;
- to form a two phase solution;
- b) adding to said two phase solution one mole equivalent of a tetraaza macrocyclic ligand precursor having the formula:
- wherein X− is an anion which provides charge neutrality, and from 1 mole equivalent to 3 mole equivalents of a reducing agent having the formula MBH4 wherein M is selected from the group consisting of lithium, sodium, potassium, and mixtures thereof;
- at a pH of at least 11 to form a macrocyclic ligand;
- c) separating the aqueous and non-aqueous phases;
- and
- d) optionally isolating said macrocyclic ligand.
A process for preparing a tetraaza macrocyclic ligand having the formula:
- wherein R is C1-C22 linear alkyl, C1-C22 branched alkyl, C7-C22 alkylenearyl, C8-C22 alkyl substituted alkylenearyl, and mixtures thereof;
- each index n is independently from 0 to 3, said process comprising the steps of:
- a) combining in a reaction vessel a one molar solution of base, said base selected from the group consisting of potassium carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, and mixtures thereof;
- and a solvent, said solvent selected from the group consisting of benzene, toluene, methanol, ethanol, n-propanol, isopropanol, diethyl ether, tetrahydrofuran, and mixtures thereof;
- wherein the ratio of said base to said solvent is from 1:10 to 1:1;
- to form a two phase solution;
- b) adding to said two phase solution, at a temperature of from 10° C. to 70° C., a tetraaza macrocyclic ligand precursor having the formula:
- wherein X− is an anion which provides charge neutrality, with from 1 mole equivalent to 3 mole equivalents a reducing agent having the formula MBH4 wherein M is selected from the group consisting of lithium, sodium, potassium, and mixtures thereof;
- at a pH of at least 11 to form a macrocyclic ligand;
- c) separating the aqueous and non-aqueous phases;
- and
- d) optionally isolating said macrocyclic ligand from said non-aqueous phase.
A process for preparing 5,12-dimethyl-1,5,8,12-tertaaza-bicyclo[6.6.2]hexadecane having the formula:
- said process comprising the steps of:
- a) combining in a reaction vessel a one molar solution of base, said base selected from the group consisting of potassium carbonate, sodium carbonate, and mixtures thereof;
- and a solvent, said solvent selected from the group consisting of ethanol, n-propanol, isopropanol, and mixtures thereof;
- wherein the ratio of the volume of said base to said volume of solvent is 1:4;
- to form a two phase solution comprising an aqueous phase and a solvent phase;
- b) adding to said two phase solution, at a temperature of from 50° C., a macrocyclic ligand precursor having the formula:
- wherein X− is an anion which provides charge neutrality, together with 2 mole equivalents of NaBH4 at a pH of at least 12 to form 4,11-dimethyl-1,4,8,11-tetraaza-bicyclo[6.6.2]hexadecane;
- c) separating from said two phase system said solvent phase;
- and
- d) isolating from said solvent phase 5,12-dimethyl-1,5,8,12-tertaaza-bicyclo[6.6.2]hexadecane.
Dependencies are inferred from the claim text.