Process for the synthesis of 4-substituted N-[(alk-2-en-1-yl)oxy]-and N-aralkyloxy-2,2,6,6-tetraalkylpiperidines
AssigneeCiba Specialty Chemicals Corporation
InventorsJoseph E. Babiarz, Stephen D. Pastor, Glen T. Cunkle
Life of this patent
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Abstract
An environmentally friendly process for the preparation of the 4-functionalized N—OR derivatives of 2,2,6,6-tetraalkylpiperidines involves the hydrogen peroxide of the corresponding N—H compound to form the corresponding N-oxyl derivative, reacting two equivalents of the N-oxyl compound with one equivalent of a compound having an allylic hydrogen, a benzylic hydrogen or an activated methine hydrogen to form one equivalent of the corresponding N—OH compound and one equivalent of the corresponding N—OR compound, and recycling the N—OH compound back to the corresponding N-oxyl compound using hydrogen peroxide or air.
Claims28
A process, involving two steps for the preparation of a selected N—OR derivative of the 2,2,6,6-tetraalkylpiperidines with a third step involving the recycling of the N—OH obtained concomitantly with the desired N—OR compound back to the corresponding N-oxyl starting material for the second step, which comprises
- in Step 1, preparing an N-oxyl compound by oxidation with hydrogen peroxide
- and,
- in Step 2, reacting two equivalents of N-oxyl with one allylic, benzylic or activated methine compound (R—H) to form one equivalent of N—OH and one equivalent of N—OR compound
- separating the N—OH and N—OR compounds, and,
- in Step 3, recycling the N—OH compound formed in Step 2 back to the N-oxyl compound needed as intermediate for Step 2
- where in the formulas A, B, C and D,
- G1 and G2 are independently alkyl of 1 to 4 carbon atoms, or G1 and G2 together are pentamethylene;
- X is hydrogen, hydroxyl, oxo, —NH—CO—E, —O—CO—E or —NH—CO—NH—E, where E is alkyl of 1 to 18 carbon atoms or said alkyl substituted by hydroxyl, or E is aryl of 6 to 10 carbon atoms;
- and
- R is an alkenyl of 3 to 20 carbon atoms;
- Y—CH—Z where Y and Z are independently, hydrogen, alkyl of 1 to 18 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one to four alkyl groups of 1 to 4 carbon atoms, provided that at least one of Y and Z is aryl and where is Y is aryl, then Z can be part of a fused ring system having methylene groups.
A process, for the preparation of a selected N—OR derivative of the 2,2,6,6-tetraalkylpiperidines followed by a subsequent step involving the recycling of the N—OH obtained concomitantly with the desired N—OR compound back to the corresponding N-oxyl starting material for the initial step, which comprises
- reacting two equivalents of N-oxyl with one allylic, benzylic or activated methine compound (R—H) to form one equivalent of N—OH and one equivalent of N—OR compound
- separating the N—OH and N—OR compounds, and,
- recycling the N—OH compound formed back to the N-oxyl compound needed as intermediate for the initial reaction
- where in the formulas B, C and D,
- G1 and G2 are independently alkyl of 1 to 4 carbon atoms, or G1 and G2 together are pentamethylene;
- X is hydrogen, hydroxyl, oxo, —NH—CO—E, —O—CO—E or —NH—CO—NH—E, where E is alkyl of 1 to 18 carbon atoms, said alkyl substituted by hydroxyl or E is aryl of 6 to 10 carbon atoms;
- and
- R is an alkenyl of 3 to 20 carbon atoms;
- Y—CH—Z where Y and Z are independently, hydrogen, alkyl of 1 to 18 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one to four alkyl groups of 1 to 4 carbon atoms, provided that at least one of Y and Z is aryl and where is Y is aryl, then Z can be part of a fused ring system having methylene groups.
A process, for the preparation of a selected N—OR derivative of the 2,2,6,6-tetraalkylpiperidines, which comprises
- reacting two equivalents of N-oxyl with one allylic, benzylic or activated methine compound (R—H) to form one equivalent of N—OH and one equivalent of N—OR compound
- separating the N—OH and N—OR compounds,
- where in the formulas B, C and D,
- G1 and G2 are independently alkyl of 1 to 4 carbon atoms, or G1 and G2 together are pentamethylene;
- X is hydrogen, hydroxyl, oxo, —NH—CO—E, —O—CO—E or —NH—CO—NH—E, where E is alkyl of 1 to 18 carbon atoms, said alkyl substituted by hydroxyl or E is aryl of 6 to 10 carbon atoms;
- and
- R is an alkenyl of 3 to 20 carbon atoms;
- Y—CH—Z where Y and Z are independently, hydrogen, alkyl of 1 to 18 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one to four alkyl groups of 1 to 4 carbon atoms, provided that at least one of Y and Z is aryl and where is Y is aryl, then Z can be part of a fused ring system having methylene groups.
Dependencies are inferred from the claim text.