Benzoylamino-acetic acid

The azlactones are first hydrolyzed with alkali to the A-benzoylamino acid and thence to 32 using an HBr-acetic acid mixture. 

When the translactonization reaction of 67 (R , R = Me, Et) was conducted in acetic acid (R" = Me) as a reaction solvent, at the boiling point, somewhat different results were obtained A mixture of products identified as the furanones 68 and the 4-benzoylamino-5-oxo-2,5-dihydrofuran-2-yl acetates 69 were obtained (Scheme 21) (97T1843). 

CN ( )-l-(4-chlorobenzoyl)-5-methoxy-2-methyl-lH-indole-3-acetic acid 2-I4-[3-[[4-(benzoylamino)-5-(dipropylamino)-1,5-dioxopentyl]oxy]propyl]-1 -piperazinyl]ethyl ester... 

The treatment of (2-benzoylamino-5-iodobenzoyl-amino)acetic acid ethyl ester 88 with hydrazine hydrate for 4h yielded hydrazine derivative 2-benzoylamino-iV-hydrazinocarbonylmethyl benzamide 89, which on refluxing with sodium acetate and acetic acid for 8 h resulted in the formation of 6-iodo-10-phenyl-3//-3,4,9,10a-tetra-azaphenanthren-2-one 90 <2000IJH59> (Scheme 5). 

Benzoylamino-6 -pyrido[l,2-a]pyrimidin-6-one 224 was prepared starting from 2-methylpyrimidine and N.TV-dimethylformamide dimethyl-acetate in boiling dimethylformamide (91BSB533). Then the resulting 2-[( )-2-(N,N-dimethylamino)ethenyl)]pyrimidine was reacted with 2-phenyl-5(4//)-oxazolone in refluxing acetic acid to give 6-oxopyrido-[l,2-a]pyrimidine 224 in 33% yield. 

H-INDOLE-3-ACETIC ACID, l-(1t-CHLOROBENZOYL)-5-METHOXY-2-METHYL-2-( t-(3-((It-(BENZOYLAMINO)-5"(DIPROPYLAMINO)-1,5-DIOXOPENTYL)OXY)PROPYL)-1 -PIPERAZINYL)ETHYL ESTER ( -)-, (Z)-2-BUTENEDI0ATE (1 2)... 

Thermally induced elimination of the elements of acetic acid from S-[( )-3-(4-methylphenyl)-2-propenyl] 2-(benzoylamino)-3-oxobutanethioate gave 5-[( )-3-(4-methylphenyl)-2-propenyl] 2-(benzoylimino)ethanethioate, which underwent IMDA reaction in situ80. 

If amino acids are treated in hot acetic acid with one molecular equivalent of acetic anhydride, the corresponding acetamino acid is formed without appreciable racemization (Enoop and Blanco, 1925). However, if the proportion of acetic anhydride is increased to two equivalents, complete racemization results (Bergmann and Zervas, 1929). This loss of optical activity could also be produced by treating an active AT-acetyl- or JV-benzoylamino acid even with less than one equivalent of acetic anhydride at 100.° Amino acid esters were not racemized by this method. With peptides interesting differences were noted. Thus glycyl-L-leucine was readily racemized, but, with L-phenylalanyl-ii-tyrosine, examination of the two amino acids after hydrolysis indicated complete racemization of the tyrosyl residue and only partial loss of activity in the phenylalanine moiety. Isovaline, which does not possess a hydrogen atom in the o-position, was not affected under the conditions used. 

The N-silylated enol acetate 1523 is cyclized by TMSOTf 20 in CHCI3, in 95% yield, giving the oxazole 1524 [57]. The dimeric derivative 1525 affords the 2,2 -bis-oxazole 1526 in 46% yield [57]. 2-Benzoylamino-3-chloropyridine 1527 is cyclized by polyphosphoric acid trimethylsilyl ester (PPSE) 195 on heating for 15 h in boiling 1,2-dichlorobenzene to give 40-60% 2-phenyloxazolo[5,4-f)]pyridine 1528 [58] (Scheme 9.34). 

The quinazoline ring of 1,2,4-triazolo[4,3-a]quinazoline 348 was formed (62TL1193) by the dehydrative cyclization of 3-benzoylamino-4,5-diphenyl-1,2,4-triazole (347). Alternatively, 1,2,4-triazolo[4,3-a]-quinazolines were prepared by assembling the fused 1,2,4-triazole ring onto the quinazoline nucleus when 2-hydrazinoquinazolines (e.g. 349) were cyclized with formic acid or acetic anhydride to give (86JHC833) angular l,2,4-triazolo[4,3-a]quinazolinones 350 in addition to linear 1,2,4-triazolo[3,4-/>]quinazolinones 351. 

Aqueous alcohol (followed by cupric acetate and then sulfuric acid) was reported by Ponzio to produce 3-benzoylamino-4-phenylfuroxan from 4-phenylfuroxan.380 Clearly, an extensive degradation has taken place of one of the two molecules of the furoxan involved in the product. 

Amino-l,2-dihydroacronycine (40 ) could be easily converted into variously substituted amines and amides. Treatment of 40 with formaldehyde and sodium borohydride afforded 2-dimethylamino-l,2-dihydroacronycine (42). Both aliphatic and aromatic amides were obtained from 4 upon treatment with acid anhydrides in pyridine. This latter reaction is exemplified by the preparation of 2-acetylamino-l,2-dihydroacronycine (43J and 2-benzoylamino-l,2-dihydroacronycine (44) using acetic anhydride and benzoic anhydride, respectively (53). 

Turchi and Cullen described the first examples of pyrazoles prepared from oxazoles (Scheme 1.231). Treatment of 5-ethoxy-p-oxo-2-phenyl-4-oxazolepropa-noic acid ethyl ester 857 with hydrazine did not afford the expected pyrazolone 858. Instead, the authors isolated ethyl-4-(benzoylamino)-5-ethoxy-l//-pyrazole-3-acet-ate 860 (R = H) in good yield. Similarly, reaction of 857 with methyUiydrazine produced 860 (R = CH3) in comparable yield. 

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