ChemInform Abstract: BASE‐CATALYZED MICHAEL ADDITION OF ACTIVE METHYLENE COMPOUNDS ON ARYLIDENE MALONATES AND ARYLIDENE BARBITURIC ACIDS

Abstract

Arylidenmalonsäureester (I) reagieren mit Malodinitril (II) zu Gemischen aus Arylidenmalodinitrilen (III) und den Lactamen (IV).

Electrophilicity of 5-Benzylidene-1,3-dimethylbarbituric and -thiobarbituric Acids

“…13 C NMR (75.5 MHz, CDCl 3 ): δ 13.7 (CH 2 CH 3 ), 14.0 (CH 2 CH 3 ), 23.6 (CH 3 -5), 28.5 (NCH 3 ), 28. (17), 206 (12), 170 (10), 165 (49), 162 (12), 161 (100), 133 (14).…”

“…Benzylidenebarbituric and thiobarbituric acids are characterized by their strongly polarized exocyclic double bond with a positive partial charge on the arylidene carbon. , They have been termed as electrically neutral organic Lewis acids , because they react with typical Lewis bases, such as alkoxides, , amines, − thiols, water, and the hydrogensulfite ion , isonitriles, phosphacumulene ylids, , or organo zinc reagents). − Because of the fact that the active double bond in benzylidenebarbituric acids can easily be reduced, − these compounds can be used for the synthesis of unsymmetrical disulfides , and for the mild oxidation of alcohols. , Furthermore, benzylidenebarbituric and -thiobarbituric acids are important building blocks in the synthesis of pyrazolo-[3,4- d ]-pyrimidine derivatives, , which show a broad biological activity. − Benzylidenethiobarbituric acids also trap radicals and, therefore, can be used as thermal stabilizers in rigid PVC …”

“…1,2 They have been termed as electrically neutral organic Lewis acids 3,4 because they react with typical Lewis bases, 5 such as alkoxides, 3,6 amines, 6-9 thiols, 10 water, 11 and the hydrogensulfite ion. 12 Benzylidenebarbituric and -thiobarbituric acids also react with carbon nucleophiles (e.g., compounds containing an active methylene group, 13,14 isonitriles, 15 phosphacumulene ylids, 16,17 or organo zinc reagents). [18][19][20] Because of the fact that the active double bond in benzylidenebarbituric acids can easily be reduced, [21][22][23] these compounds can be used for the synthesis of unsymmetrical disulfides 24,25 and for the mild oxidation of alcohols.…”