Claims
- 1. A process for preparing tetrahydropyran-4-carboxylic acid and its esters of the formula I ##STR5## where R is hydrogen, C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.8 -cycloalkyl, aryl, C.sub.7 -C.sub.12 -alkylphenyl or C.sub.7 -C.sub.12 -phenylalkyl, which comprises reacting 2,7-dioxaspiro[4.4]nonane-1,6-dione of the formula II ##STR6## with water or alcohols of the formula III
- R--OH (III),
- in the presence of acidic catalysts at from 150.degree. to 350.degree. C. and from 0.01 to 100 bar.
- 2. A process for preparing tetrahydropyran-4-carboxylic acid and its esters of formula I as defined in claim 1, wherein the reaction is carried out at from 200.degree. to 300.degree. C.
- 3. A process for preparing tetrahydropyran-4-carboxylic acid and its esters of formula I as defined in claim 1, wherein the reaction is carried out at from 220.degree. to 270.degree. C.
- 4. A process for preparing tetrahydropyran-4-carboxylic acid and its esters of formula I as defined in claim 1, wherein the acidic catalysts used are acidic oxides of elements of main groups IIIA and IVA and of sub-groups IVB to VIB of the Periodic Table of the Elements.
- 5. A process for preparing tetrahydropyran-4-carboxylic acid and its esters of formula I as defined in claim 1, wherein the catalyst used is aluminum oxide.
Priority Claims (1)
Number |
Date |
Country |
Kind |
43 00 419.9 |
Jan 1993 |
DEX |
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Parent Case Info
This is an application under 35 USC .sctn. 371 of PCT/EP 93/03670 filed Dec. 23, 1993.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/EP93/03670 |
12/23/1993 |
|
|
3/24/1995 |
3/24/1995 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO94/15931 |
7/21/1994 |
|
|
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4837346 |
Becker et al. |
Jun 1989 |
|
5371246 |
Borchers et al. |
Dec 1994 |
|
5414097 |
Fischer et al. |
May 1995 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
284969 |
Oct 1988 |
EPX |
Non-Patent Literature Citations (1)
Entry |
J. Chem. Soc. 1930, pp. 2525 to 2530. |