New isomeric 2‐ortho‐(meta‐ and para‐) chloro‐(bromo and nitro‐)benzylthio‐6‐aminouracils

Abstract

Ten new ortho, meta and para substituted derivatives of 2-benzylthio-6-aminouracils have been prepared. Electron Impact (EI) induced mass spectral fragmentation of these compounds was investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transition measurements. The correlation between the intensities of the M +. and the selected fragment ions of these compounds is discussed. The data obtained create the basis for dinstinguishing isomers. The 1 H and 13 C NMR spectra of these compounds were assigned unambiguously using a combination of heteronuclear (HETCOR) spectra the chemical shifts. The data derived from these spectra can be used to differentiate the isomers.

Synthesis and Physicochemical Characterization of Fluorescent (E)‐2‐Stilbenyloxyalkylthiouracils and Isomer Differentiation Using EIMS.

“…It has been established by us previously that the diff e rences in the values of coefficients µ are useful for diff e r e n t ation of the positional isomers of benzylthiouracils [35][36][37].…”

Time‐Efficient Synthesis of Pyrido­[2,3‐d]pyrimidinones via α‐Oxoket­enes

“…Dimethyl sulfate (1.06 mL, 11.21 mmol) was added dropwise to a solution of 6-amino-2-[(3-chlorobenzyl)thio]pyrimidin-4(3H)-one [23] (1.00 g, 3.74 mmol) in 1.0 N NaOH (11 mL) at 35°C. After stirring for 24 h, the precipitate was filtered, washed with water, and dried at 100°C to give the pure compound as a white solid (750 mg, 71 %).…”