Process for the preparation of 7-substituted 3-alkyl-3H-isobenzofuran-1-one derivatives
US7307175B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 2002 |
| Grant date | Dec 11, 2007 |
| Priority date | — |
| Expiry date | Nov 17, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C63/70
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Process for the preparation of compounds of formula (I) wherein R is halogen, R1O1R1S(O)n or (R1)2NC(X)O; R1 is C1-C8alkly, aryl-C1-C8alkyl, C1-C8haloalkyl or aryl; n is 0, 1, 2 or 3; X is O or S; and R2 is hydrogen, C1-C4alkyl or C1-C4haloalkyl, in which process, in a solvent, (1) an aniline derivative of formula (IV) wherein R is as defined above, and R3 is C1-C5alkyl or C1-C5haloalkyl, is diazotised in the presence of a mineral acid to form the corresponding diazonium salt of formul (II) wherein R and R3 are as defined above, Am− is an anion, and m is 1 or 2, (2) the resulting diazonium salt of formula (II) is carbonylated in the presence of a catalyst, CO and optionally a buffer, to form a benzoic acid derivative of formula (III) wherein R and R3 are as defined above, and (3) the benzoic acid derivative of formula (III) is then subjected to benzylic lactonisation in the ortho-position alkyl chain R3 in the presence of a free-radical initiator and a halogenating agent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.