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Last Updated: March 28, 2024

Claims for Patent: 5,569,772


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Summary for Patent: 5,569,772
Title: Process for the synthesis of benzo[b]thiophenes
Abstract:The present invention is directed to a new process for the synthesis of 2-aryl benzo[b]thiophenes, and to novel intermediates therefor.
Inventor(s): Hoard; David W. (Lafayette, IN), Luke; Wayne D. (West Lafayette, IN)
Assignee: Eli Lilly and Company (Indianapolis, IN)
Application Number:08/486,873
Patent Claims: 1. A compound of the formula ##STR8## wherein: R.sub.1 is hydrogen, C.sub.1 -C.sub.4 alkoxy, arylalkoxy, halo, or amino; and

R.sub.2 is hydrogen, C.sub.1 -C.sub.4 alkoxy, arylalkoxy, halo, or amino.

2. The compound of claim 1 wherein:

R.sub.1 is hydrogen, C.sub.1 -C.sub.4 alkoxy, or arylalkoxy; and

R.sub.2 is hydrogen, C.sub.1 -C.sub.4 alkoxy, or arylalkoxy.

3. The compound of claim 2 wherein:

R.sub.1 is hydrogen or C.sub.1 -C.sub.4 alkoxy; and

R.sub.2 is hydrogen or C.sub.1 -C.sub.4 alkoxy.

4. The compound of claim 3 wherein R.sub.1 and R.sub.2 are C.sub.1 -C.sub.4 alkoxy.

5. The compound of claim 4 wherein R.sub.1 and R.sub.2 are methoxy.

6. A process for preparing a compound of the formula ##STR9## wherein: R.sub.1 is hydrogen, C.sub.1 -C.sub.4 alkoxy, arylalkoxy, halo, or amino; and

R.sub.2 is hydrogen, C.sub.1 -C.sub.4 alkoxy, arylalkoxy, halo, or amino; which comprises reacting a compound of the formula ##STR10## wherein: R.sub.1 and R.sub.2 are as defined above, and

R.sub.3 is a thermally-labile or acid-labile C.sub.2 -C.sub.10 alkyl, C.sub.4 -C.sub.10 alkenyl, or aryl (C.sub.1 -C.sub.10 alkyl) group; with an acid catalyst at a temperature of about 100.degree. C. to about 140.degree. C., wherein the concentration of the formula II compound is about 0.05M to about 0.2M.

7. The process of claim 6 wherein:

R.sub.1 is hydrogen, C.sub.1 -C.sub.4 alkoxy, or arylalkoxy; and

R.sub.2 is hydrogen, C.sub.1 -C.sub.4 alkoxy, or arylalkoxy.

8. The process of claim 7 wherein the acid catalyst is selected from the group consisting of methanesulfonic acid, benzenesulfonic acid, 1-naphthalenesulfonic acid, 1-butanesulfonic acid, ethanesulfonic acid, 4-ethylbenzenesulfonic acid, 1-hexanesulfonic acid, 1,5-naphthalenedisulfonic acid, 1-octanesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, Nafion.RTM., Amberlyst.RTM., and Amberlite.RTM..

9. The process of claim 8 wherein the acid catalyst is selected form the group consisting of methanesulfonic acid, benzenesulfonic acid, camphorsulfonic acid, p-toluenesulfonic acid, Nafion.RTM., Amberlyst.RTM., and Amberlite.RTM..

10. The process of claim 9 wherein the acid catalyst is selected from the group consisting of methanesulfonic acid, p-toluenesulfonic acid, Nafion.RTM., Amberlyst.RTM., and Amberlite.RTM..

11. The process of claim 10 wherein R.sub.3 is a thermally-labile or acid-labile C.sub.2 -C.sub.10 alkyl or aryl (C.sub.1 -C.sub.10 alkyl) group.

12. The process of claim 11 wherein R.sub.3 is a thermally-labile or acid-labile C.sub.2 -C.sub.10 alkyl group.

13. The process of claim 12 wherein R.sub.3 is t-butyl.

14. The process of claim 13 wherein R.sub.1 and R.sub.2 are C.sub.1 -C.sub.4 alkoxy.

15. The process of claim 14 wherein R.sub.1 and R.sub.2 are methoxy.

16. The process of claim 15 wherein the acid catalyst is p-toluenesulfonic acid.

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