Process for preparing 5-phenoxy-1(3)isobenzofuranone
Inventors
Wang, Zheqing • Wu, Lillian • Zhao, Yang • Li, Zhenwei
Assignees
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Publication Number
US-10611745-B2
Publication Date
2020-04-07
Expiration Date
Abstract
The disclosure provides a simple and efficient method for producing a compound of Formula I. The method includes treating an N-substituted-4-nitro-phthalimide of Formula VII with sodium or potassium phenoxide to form an N-substituted-4-phenoxy-phthalimide of Formula VIII and then treating the N-substituted-4-phenoxy-phthalimide of Formula VIII with, for example zinc, in the presence of a base to give 5-phenoxy-1(3H)-isobenzofuranone of Formula I, its isomer of 6-phenoxy-1 (3H)-isobenzofuranone of Formula Ia, and alkyl amine or aryl amine NH2R (Formula IX)
Core Innovation
The invention relates to a process for the preparation of 5-phenoxy-1(3H)-isobenzofuranone of Formula I. The process includes treating an N-substituted-4-nitro-phthalimide of Formula VII with sodium or potassium phenoxide to form an N-substituted-4-phenoxy-phthalimide of Formula VIII.
The N-substituted 4-phenoxy-phthalimide of Formula VIII is then treated in the presence of a base with zinc, iron powder, granulated iron, tin powder, granulated tin, combinations of iron powder with ferrous sulfate, combinations of tin powder with stannous chloride, or combinations thereof. This treatment gives 5-phenoxy-1(3H)-isobenzofuranone of Formula I, its isomer 6-phenoxy-1(3H)-isobenzofuranone of Formula Ia, and alkyl amine or aryl amine NH2R of Formula IX, and the process includes isolating Formula I from Formula Ia.
The disclosure emphasizes regioselectivity toward Formula I over Formula Ia. It also describes reuse or recovery of the alkyl amine (Formula IX) to regenerate intermediate Formula VII.
Claims Coverage
The independent claims cover 2 inventive features across a two-stage sequence for preparing 5-phenoxy-1(3H)-isobenzofuranone of Formula I and isolating it from the 6-phenoxy isomer.
Phenoxide conversion of N-substituted-4-nitro-phthalimide to N-substituted-4-phenoxy-phthalimide
Treating an N-substituted-4-nitro-phthalimide of Formula VII with sodium or potassium phenoxide to form an N-substituted-4-phenoxy-phthalimide of Formula VIII.
Metal reductant treatment in base to form Formula I and isolate from Formula Ia
Treating the N-substituted 4-phenoxy-phthalimide of Formula VIII with zinc, iron powder, granulated iron, tin powder, granulated tin, combinations of iron powder with ferrous sulfate, or combinations of tin powder with stannous chloride, in the presence of a base to give 5-phenoxy-1(3H)-isobenzofuranone of Formula I, its isomer of 6-phenoxy-1(3H)-isobenzofuranone of Formula Ia, and alkyl amine or aryl amine NH2R of Formula IX, and isolating Formula I from Formula Ia.
The inventive coverage centers on converting Formula VII to Formula VIII using sodium or potassium phenoxide, then reductively treating Formula VIII with specified metal or metal/metal-salt compositions in the presence of a base to produce Formula I together with Formula Ia and Formula IX, with isolation of Formula I from Formula Ia.
Stated Advantages
Regioselectivity toward 5-phenoxy-1(3H)-isobenzofuranone (Formula I) over 6-phenoxy-1(3H)-isobenzofuranone (Formula Ia).
Low waste via elimination of heavy-metal reagents.
Purification by recrystallization or slurry.
Reuse or recovery of amine (Formula IX) to regenerate intermediate Formula VII.
Documented Applications
Preparation of 5-phenoxy-1(3H)-isobenzofuranone of Formula I using a greener, efficient 2-step process, including isolation of Formula I from the Formula Ia isomer.
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