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Self‐Acylation of 1‐Adamantylacetic Acid in Trifluoroacetic Anhydride Medium: A Route to 2,4‐Bis(1‐adamantyl)acetoacetic Acid and Its Derivatives
Author(s) -
Kovalev Vladimir,
Shokova Elvira,
Shmailov Alexander,
Vatsouro Ivan,
Tafeenko Viktor
Publication year - 2010
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201000312
Subject(s) - chemistry , acylation , trifluoroacetic acid , trifluoroacetic anhydride , organic chemistry , acetoacetic ester synthesis , thiourea , medicinal chemistry , catalysis
The self‐acylation of 1‐adamantylacetic acid ( 1 ) in trifluoroacetic anhydride, catalyzed by triflic acid, proceeds through the formation of the mixed 2,4‐bis(1‐adamantyl)acetoacetic–trifluoroacetic anhydride 2 , and it was used as an efficient approach to previously unknown 2,4‐bis(1‐adamantyl)acetoacetic acid ( 3 ), its esters 4 – 6 and amides 7 – 11 , and the sterically hindered 1‐adamantyl(1‐adamantylacetyl)ketene ( 12 ). The latter is stable in solution and can be isolated as a neat solid. Addition of methanol or primary amines to 12 gave the corresponding derivatives of acid 3 . Acid 3 was decarboxylated to 1,3‐bis(1‐adamantyl)acetone ( 22 ), whereas theheterocyclization of phenyl ester 6 with thiourea gave two isomeric adamantylated thiouracils 23 and 24 . The structures of N ‐benzylamide 7 and thiouracil 23 were confirmed by single‐crystal X‐ray analysis. The utilization of the self‐acylation method for the conversion of some other aliphatic acids is discussed and preliminarily tested.