Synthesis of 5‐(functionalized acyl)‐1,3‐dialkyl‐substituted barbituric and 2‐thiobarbituric acids

Abstract

A sodium derivative of 1,3-dimethylbarbituric acid or 1,3-diethyl-2-thiobarbituric acid undergoes an efficient monoacylation at C5 by the reaction with ω-chloroalkanoyl chloride or diacid dichloride in the presence of pyridine in tetrahydrofuran. A nucleophilic displacement of the chlorine in a 5-chloroacetylbartiburate can be accomplished by using a one-pot procedure. By contrast, a similar transformation of a 5-(chlorobutanoyl)barbituric acid requires intramolecular cyclization in the presence of a nonnucleophilic base followed by treatment with a nucleophile of the resultant 5-[4,5-dihydro(3H)-2-furylidene]barbiturate.

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

“…The sodium derivatives of 1,3-dialkylbarbituric acid or 2-thiobarbituric acid derivatives 256 undergo monoacylation at C–5 to give the corresponding 5-chloroacetyl derivatives 258 which cyclized on treatment with Et 3 N in ethanol to give the corresponding furano[3,2- e ]pyrimidindione deri-vatives 259 ( Scheme 76 ) [ 506 ].…”

Behavior of 2‐iminothiazolidin‐4‐one with different reagents

“…There is an interest for introduction of a substituent at C-5 of pyrimidine moiety because biological activity enhancement of the products formed [23][24][25]. Therefore, this prompted us to prepare ethyl 3,7-dioxo-5-phenyl-3,5,6,7-tetrahydro-2H-thiazolo[3,2-a]pyrimidine-6-carboxylate (18) through the cyclocondensation of 5 with benzylidenemalonate which is formed in situ was unsuccessful.…”

A Versatile Synthesis, PM3‐Semiempirical, Antibacterial, and Antitumor Evaluation of Some Bioactive Pyrazoles

“…Because of the enhanced biological activity of pyrimidine moiety [20], it was of interest to introduce a substituent at position 5 of this moiety, whereby a highly conjugated derivative 5 can be synthesized. Treatment of 1 with triethylorthoformate and 6‐aminothioruacil or glycine afforded methylidene‐dipyrazolinone 6 .…”