Silica-bonded N-propyldiethylenetriamine sulfamic acid (SPDTSA) is employed as a recyclable heterogeneous solid acid catalyst for the synthesis of benzopyrano[2,3-d]pyrimidines  through one-pot condensation reaction of salicylaldehydes, malononitrile and secondary amines  at room temperature under solvent-free conditions. SPDTSA showed much the same efficiency when used in con...

BACKGROUND Pyrazolo[1,5-a]pyrimidines are purine analogues. They have beneficial properties as antimetabolites in purine biochemical reactions. This division compounds have attracted wide pharmaceutical interest because of their antitrypanosomal activity. RESULTS The present work depicts an effective synthesis convention of pyrazolo[1,5-a]pyrimidines, pyrazolo[5,1-c]triazines, thieno[2,3-b]py...

* Present address: Department of Chemistry, College of Science, Sulaimaniya, Iraq. Dimers/Radiolysis/Pyrimidines/N2O Aqueous solutions of pyrimidines (such as uracil and thymine) containing N2O (125 mM) were irradiated with Co-60 gamma rays source and analysed with paper chromatography technique using suitable solvent developing systems. Among the various radiation-induced products, the three d...

The algebraic structures of the genetic code are most important to obtain additional information about the semantic code and its applications. In this paper we define two dual Boolean codon lattices of the genetic code using hydrogen bond numbers and the chemical types of bases: purines and pyrimidines. The Boolean lattices reflect the role of hydrophobicity in the distribution of codon assignm...

5-Aryl-7-hydrazino-2-phenylpyrazolo[1,5-c]pyrimidines 1 were used as precursors for the preparation of a new series of 5-aryl-8-phenylpyrazolo[1,5-c]-1,2,4- triazolo[4,3-a]pyrimidines 2. The reactions of 2 with certain electrophilic reagents gave the respective 6-substituted derivatives 3-5 rather than the 7-isomeric products. Formylation of the key compounds 1 with ethyl formate yielded the fo...

The title compound, C(32)H(28)N(6)O(4)·2C(2)H(5)OH, consists of two 2-(propyl-amino)-benzofuro[3,2-d]pyrimidin-4(3H)-one units connected, via one of the pyrimidine N atoms, to a bridging benzene ring in the 1,4 positions. Two ethanol solvent mol-ecules are also present. The main mol-ecule lies on a center of symmetry located at the center of the benzene ring. The fused-ring system of the benzof...

I investigations carried out in this laboratory have been concerned with the initial responses of the corneal stromal cells to injury. One reaction which occurs in the stromal cells within a few hours after injury to the cornea is the activation of the fibrocytes to take up the vital dye, neutral red.' This reaction does not occur in the normal corneal stromal cells of the rat, but cells activa...

A new and facile synthesis of 2-thioxoquinazolin-4-ones by introducing a benzenoid system in the pyrimidine moiety by reacting ethoxymethylene derivatives of 1,3-diarylthiobarbituric acids (DTBA) with active methylene compounds, such as malononitrile and ethyl cyanoacetate, in presence of ZnCl₂ has been developed.