4,6-Diamino-1H-pyrimidine-2-thione (1) was used for the preparation of pyrimidine derivatives 2-5. Compound 5 was cyclized to produce pyrimido[2,1-b][1,3]thiazine derivative 6 which was condensed with p-chlorobenzaldehyde to give compound 7. The latter compound was reacted with hydroxylamine to give isoxazolo[4,5-d]thiazino[2,3-a]pyrimidine 8. Compound 8b was treated with 2-chloroethyl methyl e...

A room-temperature electrochemical strategy for hydrogenation (deuteration) and reverse dehydrogenation of N-heterocycles over a bifunctional MoNi4 electrode is developed, which includes the quinoxaline using H2O as hydrogen source with 80% Faradaic efficiency hydrogen-rich 1,2,3,4-tetrahydroquinoxaline up to 99% yield selectivity. The in situ generated active atom (H*) plausibly involved quino...

The chain persistency of single-stranded (ss) DNA at a high-salt limit mainly arises from the so-called base-stacking interaction between consecutive bases along the strand. Stacking is appreciable for purine–purine (e.g., A–A) and purine–pyrimidine stacks (e.g., A–T), but it is weak for pyrimidine stacks (i.e., T–T, T–C, and C–C). We study how base stacking can stiffen the strand by classifyin...

We have found that the anaerobic protozoan parasite Giardia lamblia is incapable of de novo pyrimidine metabolism, as shown by its inability to incorporate orotate, bicarbonate, and aspartate into the pyrimidine nucleotide pool. Results from high performance liquid chromatography of pyrimidine and pyrimidine nucleoside pulse-labeled nucleotide pools and enzyme assays suggest that the parasite s...

In the title compound, C(6)H(10)N(3) (+)·C(7)H(3)N(2)O(6) (-)·2H(2)O, the amino-pyrimidine mol-ecule is protonated at one of the pyrimidine N atoms. The carboxyl-ate group of the 3,5-dinitro-benzoate anion inter-acts with the protonated pyrimidine N atom and the 2-amino group through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) motif. Two inversion-related pyrimidine rings are linked ...

In the biogenesis of riboflavin by the yeast, Eremothecium ashbyii, carbon atoms constituting the pyrimidine ring of adenine were incorporated into the 6,7-dimethylisoalloxazine ring of riboflavin with much greater efficiency than was the 8 position of the purine ring (1). It remained to determine whether the carbon atoms which constitute the pyrimidine ring of the purine are incorporated direc...

Understanding prebiotic nucleotide synthesis is a long standing challenge thought to be essential to elucidating the origins of life on Earth. Recently, remarkable progress has been made, but to date all proposed syntheses account separately for the pyrimidine and purine ribonucleotides; no divergent synthesis from common precursors has been proposed. Moreover, the prebiotic syntheses of pyrimi...

In this article we present a model for molecularly imprinted polymers, which considers both complexation processes in the pre-polymerization mixture and adsorption in the imprinted structures within a single consistent framework. As a case study we investigate MAA/EGDMA polymers imprinted with pyrazine and pyrimidine. A polymer imprinted with pyrazine shows substantial selectivity towards pyraz...

Coumarin derivatives containing pyrazolo[1,5-a]pyrimidine, tetrazolo[1,5-a]pyrimidine, imidazo[1,2-a]pyrimidine, pyrazolo[3,4-d]pyrimidine, 1,3,4-thiadiazoles and thiazoles were synthesized from 6-bromo-3-(3-(dimethylamino)acryloyl)-2H-chromen-2-one, methyl 2-(1-(6-bromo-2-oxo-2H-chromen-3-yl)ethylidene)hydrazine carbodithioate, 2-(1-(6-bromo-2-oxo-2H-chromen-3-yl)ethylidene) hydrazine carbothi...

In the crystal structure of the title polymeric complex, [Ca(C(5)H(3)N(2)O(2))(2)](n), the Ca(II) cation has site symmetry m2 and is N,O-chelated by four pyrimidine-2-carboxyl-ate anions in a square-anti-prismatic geometry. The planar pyrimidine-2-carboxyl-ate anion is located on a crystallographic special position, three C atoms have site symmetry 2mm, while the carboxyl O atom, the pyrimidine...