Claims for Patent: 5,569,772

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):	David W. Hoard, Wayne D. Luke
Assignee:	Eli Lilly and Co
Application Number:	US08/486,873
Patent Claims:	1. A compound of the formula ##STR8## wherein: R1 is hydrogen, C1 -C4 alkoxy, arylalkoxy, halo, or amino; andR2 is hydrogen, C1 -C4 alkoxy, arylalkoxy, halo, or amino. 2. The compound of claim 1 wherein:R1 is hydrogen, C1 -C4 alkoxy, or arylalkoxy; and R2 is hydrogen, C1 -C4 alkoxy, or arylalkoxy. 3. The compound of claim 2 wherein:R1 is hydrogen or C1 -C4 alkoxy; and R2 is hydrogen or C1 -C4 alkoxy. 4. The compound of claim 3 wherein R1 and R2 are C1 -C4 alkoxy. 5. The compound of claim 4 wherein R1 and R2 are methoxy. 6. A process for preparing a compound of the formula ##STR9## wherein: R1 is hydrogen, C1 -C4 alkoxy, arylalkoxy, halo, or amino; andR2 is hydrogen, C1 -C4 alkoxy, arylalkoxy, halo, or amino; which comprises reacting a compound of the formula ##STR10## wherein: R1 and R2 are as defined above, and R3 is a thermally-labile or acid-labile C2 -C10 alkyl, C4 -C10 alkenyl, or aryl (C1 -C10 alkyl) group; with an acid catalyst at a temperature of about 100° C. to about 140° C., wherein the concentration of the formula II compound is about 0.05M to about 0.2M. 7. The process of claim 6 wherein:R1 is hydrogen, C1 -C4 alkoxy, or arylalkoxy; and R2 is hydrogen, C1 -C4 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®, Amberlyst®, and Amberlite®. 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®, Amberlyst®, and Amberlite®. 10. The process of claim 9 wherein the acid catalyst is selected from the group consisting of methanesulfonic acid, p-toluenesulfonic acid, Nafion®, Amberlyst®, and Amberlite®. 11. The process of claim 10 wherein R3 is a thermally-labile or acid-labile C2 -C10 alkyl or aryl (C1 -C10 alkyl) group. 12. The process of claim 11 wherein R3 is a thermally-labile or acid-labile C2 -C10 alkyl group. 13. The process of claim 12 wherein R3 is t-butyl. 14. The process of claim 13 wherein R1 and R2 are C1 -C4 alkoxy. 15. The process of claim 14 wherein R1 and R2 are methoxy. 16. The process of claim 15 wherein the acid catalyst is p-toluenesulfonic acid.