US 11,753,379 B2
Process for forming 2-hydroxypyridine-1-oxide or derivatives thereof
Ute Back, Blankenbach (DE); Dirk Fischer, Hahnheim (DE); Sidonie Vollrath, Frankfurt am Main (DE); Lothar Fisch, Idstein (DE); and Thierry Muller, Ettelbruck (LU)
Assigned to CLARIANT INTERNATIONAL LTD, Muttenz (CH)
Appl. No. 17/59,144
Filed by Clariant International Ltd., Muttenz (CH)
PCT Filed May 27, 2019, PCT No. PCT/EP2019/063663
§ 371(c)(1), (2) Date Nov. 25, 2020,
PCT Pub. No. WO2019/228988, PCT Pub. Date Dec. 5, 2019.
Claims priority of application No. 18175246 (EP), filed on May 30, 2018.
Prior Publication US 2021/0214307 A1, Jul. 15, 2021
Int. Cl. C07D 213/89 (2006.01); C07C 215/08 (2006.01)
CPC C07D 213/89 (2013.01) [C07C 215/08 (2013.01)] 16 Claims
 
1. A process comprising the steps of:
(a) providing a solution comprising:
(i) at least one solvent, wherein the solvent is selected from the group consisting of ethanol, methanol, and mixtures thereof;
(ii) at least one acid;
(iii) at least one compound according to Formula (1)

OG Complex Work Unit Chemistry
wherein
R1 is selected from the group consisting of H, a non-substituted or halogen-substituted, branched or unbranched C1-C20-alkyl radical, a non-substituted or halogen-substituted C5-C8-cycloalkyl radical, a non-substituted or halogen-substituted C8-C10-aryl radical or a non-substituted or halogen-substituted, branched or unbranched C7-C20-aralkyl radical;
R2 is either O or S,
R3 is H or a branched or unbranched C1-C4-alkyl radical;
A1 is selected from the group consisting of H, a non-substituted halogen-substituted, branched or unbranched C1-C20-alkyl radical, a non-substituted or halogen-substituted C5-C8-cycloalkyl radical, a branched or unbranched hydroxylated C1-C20-alkyl radical;
A2 is selected from the group consisting of H, a non-substituted halogen-substituted, branched or unbranched C1-C20-alkyl radical, a non-substituted or halogen-substituted C5-C8-cycloalkyl radical, a branched or unbranched hydroxylated C1-C20-alkyl radical;
A3 is selected from the group consisting of H, a non-substituted halogen-substituted, branched or unbranched C1-C20-alkyl radical, a non-substituted or halogen-substituted C5-C8-cycloalkyl radical, a branched or unbranched hydroxylated C1-C20-alkyl radical;
(b) heating the solution to at least 35° C.; and
(c) recovering a compound according to Formula (2)

OG Complex Work Unit Chemistry
wherein
R1x is selected from the group consisting of H, an unsubstituted or halogen-substituted, branched or unbranched C1-C20-alkyl radical, an unsubstituted or halogen-substituted C5-C8-cycloalkyl radical, an unsubstituted or halogen-substituted C8-C10-aryl radical or an unsubstituted or halogen-substituted, branched or unbranched C7-C20-aralkyl radical;
R2x is either O or S,
R3x is H or a branched or unbranched C1-C4-alkyl radical.