Hippuric acid, phenyl ester

The possibility of the triazene linking system for the ester-enolate imine condensation was initially investigated on model compounds 110 and 111 (Scheme 35). Dibenzyltriazene 110 was used as a model compound for monobactam derivatives and prepared by diazotization of hippuric acid methyl ester. Dibenzyltriazene 111 was used as a model compound for 3-phenyl-substituted azetidin-2-ones and prepared by diazotization of 2-(4-aminophenyl)-propionic acid methyl ester and conversion with dibenzylamine in 64% overall yield. The low yields of /V-unsub-stituted lactams, during the model studies, hint at a problematic transfer to solid support. 

Hippuric acid Ph ester, in H-00078 A -Hydroxy-3-(4-hydroxyphenyl)-A -phenyl-2-propenamide, H-00241... 

Azlactones 12 were obtained from hippuric acid (11, R2=phenyl) in higher purity and in better yield than those from N-acetylglycine (11, R2=methyl). The question as to which of the aldehydes, vanillin (10, Rj= acetyl) or veratrumaldehyde (10, R3 = methyl), should be chosen was decided by the availability of the latter at a relatively low price from Italy. By asymmetric hydrogenation applying [Rh(Ph-/ -glup)(cod)]BF4 (see formula 15, cod=ds,ds-cydoocta-l,5-diene, A =tetrafluoroborate) all acid substrates led to higher enantioselectivities than their esters (Tab. 1) [12]. 

Benzoylacetyl. See 1-Phenyl-1,2-propanedione Benzoyl alcohol. See Benzyl alcohol Benzoylaminoacetic acid. See Hippuric acid o-(Benzoylamino) diphenyl disulfide. See 2,2 -Dibenzamidodiphenyl disulfide Benzoylbenzene. See Benzophenone 2-Benzoyl benzoic acid methyl ester o-Benzoylbenzoic acid methyl ester. See o-M ethyl benzoyl benzoate 4-Benzoylbiphenyl... 

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