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Ethyl 2-amino-5-ethylthiophene-3- carboxylate 1, obtained from the reaction of butyraldehyde, ethyl cyanoacetate, sulfur, and triethylamine, reacted with benzoylisothiocyanate to give the corresponding ureido derivatives 2 in a high yield. Further reactions of the compound 2 with an aqueous-alcohol solution of potassium hydroxide and then with hydrochloric acid gave the 2-thio-thieno[2,3-d]pyrimidine-4-ones 3, which were reacted with RX to give novel compounds 4a-4i. Treating the compound 3 with dibromoalkane led to the formation of triacylic compounds 5j-5m. Their structures were clearly verified by IR, 1H NMR, EI-MS spectroscopy, and elemental analysis. The results of a preliminary bioassay indicated that some compounds possess excellent inhibitory activities against the root and the stalk of Brassica napus (rape) and Echinochloa crusgalli (barnyard grass) at a dosage of 100 mg/L. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. [ABSTRACT FROM AUTHOR]

Abstract  An efficient, fast and facile pyrazolo[1,5-a]pyrimidine synthetic protocol has been established by the condensation of aminopyrazoles with 1,3-dicarbonyl components in AcOH/H2SO4 system. The pyrazolo[1,5-a]pyrimidine sulfides were selectively oxidized to the sulfones via a temperature-controlled stepwise oxidative fashion. The correlation between the substitution patterns of these pyrazolo[1,5-a]pyrimidines and their fluorescent spectroscopic properties were further examined, which provided the fundamentals for their potential applications in the development of new fluorescent probes. Red-shifts were easily achieved by the incorporation of unsaturated groups at the 5- and 7-positions, which suggested an approach for synthesizing long wavelength pyrazolo[1,5-a]pyrimidine dyes. The fluorescent spectroscopic properties were found to be sensitive to the hydroxy-containing and carbonyl-containing media such as alcohol and acetone, which helps to confirm the promising perspectives of further investigations in this area. [ABSTRACT FROM AUTHOR]

In the title molecule, C18H25N3O2S, the central thienopyrimidine ring system is essentially planar. The cyclohexene ring, in which the four CH2 groups are disordered in an approximately 1:1 ratio, adopts a half-chair conformation, while the morpholine ring is in a standard chair conformation. The butyl group is disordered in an approximately 2:1 ratio. In the crystal structure, weak intermolecular C—H⋯O hydrogen-bonding interactions stabilize the crystal structure. [ABSTRACT FROM AUTHOR]

The tetra­hydro­pyrimidine ring of the title mol­ecule, C12H14N2OS, adopts a half-chair conformation. In the crystal structure, the mol­ecules are linked to form centrosymmetric­ally related hydrogen-bonded dimers. [ABSTRACT FROM AUTHOR]

The article presents information related to the organic compound 3-(2-Chlorobenzyl)-2-thioxoperhydro-pyrimidin-4-one. The tetrahydropyrimidine ring of the compound adopts a half-chair conformation. The derivatives of uracil and thiouracil are known for their varied bioactivity. Lenacil, bromacil, butafenacil, flupropacil, isocil and terbacil are widely used as herbicides. Some of them possess antidiabetic activity. This led researchers to pay more attention to the synthesis and structure determination of these compounds.

The tetra­hydro­pyrimidine ring of the title mol­ecule, C11H11FN2OS, adopts a half-chair conformation. In the crystal structure, the mol­ecules are linked to form centrosymmetric hydrogen-bonded dimers. [ABSTRACT FROM AUTHOR]