Chaykovsky, Michael et al. published their research in Journal of Medicinal Chemistry in 1977 | CAS: 7413-34-5

Sodium (S)-2-(4-(((2,4-diaminopteridin-6-yl)methyl)(methyl)amino)benzamido)pentanedioate (cas: 7413-34-5) belongs to amides. The solubilities of amides and esters are roughly comparable. Typically amides are less soluble than comparable amines and carboxylic acids since these compounds can both donate and accept hydrogen bonds. Tertiary amides, with the important exception of N,N-dimethylformamide, exhibit low solubility in water. Amides are not in general accessible by the direct condensation of amines with carboxylic acids for two reasons: first, both components are readily deactivated by a transfer of a proton from the acid to the amine and second, the hydroxy unit on the carbonyl of the acid is a relatively poor leaving group. Nevertheless, the formation of five- and six-membered rings is often surprisingly simple provided that other factors can be brought into play to assist in the condensation.COA of Formula: C20H20N8Na2O5

Methotrexate analogs. 9. Synthesis and biological properties of some 8-alkyl-7,8-dihydro analogs was written by Chaykovsky, Michael;Hirst, Margaret;Lazarus, Herbert;Martinelli, Jack E.;Kisliuk, Roy L.;Gaumont, Yvette. And the article was included in Journal of Medicinal Chemistry in 1977.COA of Formula: C20H20N8Na2O5 This article mentions the following:

Eight title derivatives were prepared by direct alkylation of 7,8-dihydromethotrexate (I) [14009-31-5]. I and 8-methyl-7,8-dihydromethotrexate (II) [54820-64-3] were comparable to methotrexate (MTX) in their inhibition of Lactobacillus casei growth. I and all its derivatives were less inhibitory toward dihydrofolate reductase [9002-03-3] than MTX, but all were more inhibitory towared thymidylate synthetase [9031-61-2] from L. casei. I was about as active as MTX in vitro against CCRF-CEM human lymphoblastic cells, but was inactive against L1210 leukemia in mice. The 8-alkyl derivatives of I were much less toxic than I, and several derivatives had some in vivo activity against L1210 leukemia. In the experiment, the researchers used many compounds, for example, Sodium (S)-2-(4-(((2,4-diaminopteridin-6-yl)methyl)(methyl)amino)benzamido)pentanedioate (cas: 7413-34-5COA of Formula: C20H20N8Na2O5).

Sodium (S)-2-(4-(((2,4-diaminopteridin-6-yl)methyl)(methyl)amino)benzamido)pentanedioate (cas: 7413-34-5) belongs to amides. The solubilities of amides and esters are roughly comparable. Typically amides are less soluble than comparable amines and carboxylic acids since these compounds can both donate and accept hydrogen bonds. Tertiary amides, with the important exception of N,N-dimethylformamide, exhibit low solubility in water. Amides are not in general accessible by the direct condensation of amines with carboxylic acids for two reasons: first, both components are readily deactivated by a transfer of a proton from the acid to the amine and second, the hydroxy unit on the carbonyl of the acid is a relatively poor leaving group. Nevertheless, the formation of five- and six-membered rings is often surprisingly simple provided that other factors can be brought into play to assist in the condensation.COA of Formula: C20H20N8Na2O5

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics