Process for the production of 2H-1-benzopyrans
US5919953A · kind A · utility
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10Claims
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Key dates
| Filing date | Aug 11, 1998 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Aug 11, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D311/58
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
There is provided a 2-stage process for making 2H-1-benzopyrans wherein an alpha,beta-unsaturated aldehyde is reacted with an alkanol or an alkane-diol in the presence of a dehydrating compound which is an orthoformate and an aluminum oxide/silicon oxide catalyst to form an aliphatic acetal, which is then condensed in a second stage with a phenol in the presence of base in an organic solvent.
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