Amino acid derivatives, part 2: Synthesis, antiviral, and antitumor activity of simple protected amino acids functionalized at <i>N</i>‐terminus with naphthalene side chain

Self Cite

Methyl 2-[2-(3-acetyl-4-methyl-2-oxo-1,2-dihydroquinolin-1-yl)acet-amido] alkano-ate 7; Oregioisomers 12 and N-substituted dipeptides 14 were efficiently prepared by azide coupling of amino acid esters with the azide derivatives 5, 11 and 13, respectively. Further the N-substituted ester 7 reacted with N 2 H 4 .H 2 O to give the hydrazide 8 which was condensed with furan-2-carbaldehyde to exhibit the hydrazone 9.

Section: Methodsmentioning

confidence: 99%

Convenient syntheses of methyl 2-[2-(3-acetyl-4-methyl-2-oxo-1,2-dihydroquinolin-1-yl)acetamido] alkanoates and their O-regioisomers

Ali¹,

Fathalla²,

Rayes³

2008

Self Cite

“…The synthesis of the target thioacetyl amino acid derivatives 8a-g were efficiently formed from key intermediate ester 2 via the azide coupling method, [16][17][18] which was reported to minimize the degree of racemization in amino acid coupling. The in situ generated azide 4 solution in ethyl acetate reacted with amino acid methyl ester hydrochloride 7 in the presence of triethyl amine to afford the methyl-2-(2-(4,5-dihydro-4-methyl-5-oxo- [1,2,4]triazolo [4,3-a]quinazolin-1-yl-thio)acetamido) alkanoate 8a-g in good yield, scheme 2.…”

Section: Methodsmentioning

confidence: 99%

Convenient synthesis of 1-substituted-4-methyl-5-oxo [1,2,4]triazolo[4,3-a]quinazolines

Fathalla¹,

Rayes²,

Ali³

2007

Self Cite

A new and convenient synthesis of a variety of methyl-2-(2-(4,5-dihydro-4-methyl-5-oxo-[1,2,4]triazolo[4,3-a]quinazolin-1-yl-thio) acetamido and propanamido alkanoate 8a-h and 9a-c, respectively has been developed via azide and DCC coupling methods. Hydrazinolysis of the ester 8a-g gave the hydrazide 10a-g, which subsequently reacted with furfural to give the hydrazone 11a-f. Compounds 8-11 might show non sedative H1-antihistamines activities. Compounds 8-11 were characterized by elemental analysis, IR, mass and 1 H NMR data.

“…Currently, HOBt is used very frequently as activating agent for the coupling of carboxylic acid group and amino group, not only because the coupling process is fast, but also it suppresses racemization, especially in the presence of DCC. [30][31][32][33] Thus, the peptides 5a-e were prepared by coupling of 2b with the appropriate L-amino acid methyl ester hydrochloride in the presence of HOBt and DCC as coupling reagents in 81-87% yields. Alternatively, 2a was boiled with hydrazine hydrate in ethanol to afford the hydrazide 3 34 which subsequently converted into the new azide 4 by treatment with NaNO 2 /HCl mixture.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of chiral N-(2-(1-oxophthalazin-2(1H)-yl) ethanoyl)-α-amino acid derivatives as antitumor agents

El‐Nezhawy¹,

Radwan²,

Gaballah³

2009

A series of chiral α-amino acid derivatives conjugated with 1-oxophthalazine moiety 5a-e were synthesized by coupling of various L-acylated amino acid derivatives with 2-(1-oxophthalazin-2(1H)-yl)acetic acid in the presence of 1-hydroxybenzotriazole (HOBt) and N,N`-dicyclohexylcarbodiimide (DCC) as coupling reagent. Alternatively, compounds 5a-e were prepared by the reaction of the corresponding aizde 4, via the azide-coupling method, with Lacylated amino acid derivatives. The peptide esters 5a-d were converted into their corresponding amides 6a-d by treating with methanolic ammonia. Moreover, 5a was boiled with hydrazine hydrate to afford the corresponding hydrazide 7. Finally, the dipeptides 8a-c were prepared by coupling of 5a with the appropriate L-amino acid methyl ester. The synthesized compounds were tested against Caucasian breast adenocarcinoma MCF7 cell line.