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Erlenmeyer—Plochl azlactone synthesis

Formation of 5-oxazolones (or azlactones ) by intramolecular condensation of acylglycines in the presence of acetic anhydride. [Pg.212]

Erlenmeyer, E., Jr. Ann. 1893, 275, 1. Emil Erlenmeyer, Jr. (1864—1921) was bom in Heidelberg, Germany to Emil Erlenmeyer (1825—1909), a famous chemistry professor at the University of Heidelberg. He investigated the Erlenmeyer-Plochl azlactone synthesis while he was a Professor of Chemistry at Strasburg. [Pg.212]

Brooks, D. A. Erlenmeyer—Plochl Azlactone Synthesis in Name Reactions in Heterocyclic Chemistry, Li, J. J. Corey, E. J., Eds. Wiley Sons Hoboken, NJ, 2005, 229-233. (Review). [Pg.213]

Name Reactions, 4th ed., DOI 10.1007/978-3-642-01053-8 88, Springer-Verlag Berlin Heidelberg 2009 [Pg.204]

He investigated the Erlenmeyer-Plochl azlactone synthesis while he was a Professor of Chemistry at Strasburg. The Erlenmeyer flasks are ubiquitous in organic chemistry laboratories. [Pg.205]

The azlactones of a-benzoylaminocinnamic acids have traditionally been prepared by the action of hippuric acid (1, Ri = Ph) and acetic anhydride upon aromatic aldehydes, usually in the presence of sodium acetate. The formation of the oxazolone (2) in Erlenmeyer-Plochl synthesis is supported by good evidence. The method is a way to important intermediate products used in the synthesis of a-amino acids, peptides and related compounds. The aldol condensation reaction of azlactones (2) with carbonyl compounds is often followed by hydrolysis to provide unsaturated a-acylamino acid (4). Reduction yields the corresponding amino acid (6), while drastic hydrolysis gives the a-0X0 acid (5).  [Pg.229]

In 1959, Crawford and Little reported superior yields of 3 in reactions of aromatic aldehydes by using isolated, crystalline 2-phenyloxazol-5-one (2, Ri = Ph) compared to direct reaction with hippuric acid (1, Ri = Ph). An early report by Boekelheide and Schramm on the use of ketones in the Erlenmeyer azlactone synthesis includes treatment [Pg.229]

Comforth has reviewed literature reports and independently studied the special cases of reaction of 1 with salicylaldehyde and with 2-acetoxybenzaldehyde. Coumarins (10) are afforded in the condensation of 1 with salicylaldehyde or its imine, whereas when 2-acetoxybenzaldehyde is used, acetoxy oxazolone 12 is the major product. The initial aldol condensation product between the oxazolone and 2-acetoxybenzaldehyde is the 4-(a-hydroxybenzyl)oxazolone 11, in which base-catalyzed intramolecular transacetylation is envisioned. The product 9 (R = Ac) can either be acetylated on the phenolic hydroxy group, before or after loss of acetic acid, to yield the oxazolone 12, or it can rearrange, by a second intramolecular process catalyzed by base and acid, to the hydrocoumarin, which loses acetic acid to yield 10. When salicylaldehyde is the starting material, aldol intermediate 9 (R = H) can rearrange directly to a hydrocoumarin. Comforth also accessed pure 4-(2 -hydroxyphenylmethylene)-2-phenyloxazol-5(4//)-one (13) through hydrolysis of 12 with 88% sulfuric acid. [Pg.230]

Bismuth(III) acetate catalyzes the synthesis of azlactones (17) from aromatic aldehydes in moderate to good yields via the Erlenmeyer synthesis. While the standard procedure for azlactone synthesis consists of using a stoichiometric amount of fused anhydrous sodium acetate, 10 mol% of Bi(OAc)3 is sufficient to catalyze the reaction and the crude product is found to be 98% pure. [Pg.231]


Formation of 5-oxazolones (or azlactones ) (2) by intramolecular condensation of acylglycines (1) in the presence of acetic anhydride is known as the Erlenmeyer-Plochl azlactone synthesis. ... [Pg.229]

A variant of the Perkin reaction is the Erlenmeyer-Plochl-azlactone synthesis By condensation of an aromatic aldehyde 1 with an N-acyl glycine 5 in the presence of sodium acetate and acetic anhydride, an azlactone 6 is obtained via the following mechanism ... [Pg.226]

This reaction is related to the Erlenmeyer-Plochl Azlactone Synthesis. [Pg.355]


See other pages where Erlenmeyer—Plochl azlactone synthesis is mentioned: [Pg.219]    [Pg.229]    [Pg.212]    [Pg.698]    [Pg.997]    [Pg.997]    [Pg.998]    [Pg.1000]    [Pg.204]    [Pg.205]    [Pg.230]    [Pg.652]    [Pg.718]    [Pg.204]   
See also in sourсe #XX -- [ Pg.226 ]

See also in sourсe #XX -- [ Pg.204 ]

See also in sourсe #XX -- [ Pg.204 ]




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