The present work reports the synthesis of three new nitrogen-containing heteronuclear molecules (two pyrimidines and one pyrrolopyrimidine). Based on the 12 principles of green chemistry, chemical methodologies are planned and executed. Various phase transfer catalysts were examined in the crucial step to execute C?N bond formation (through the SnAr mechanism), TBAI was found to be a better option than those of TBAB and CTAB. The one-pot synthetic methodology was optimized involving Wittig olefination and bromination to achieve a key precursor for the synthesis of a new pyrrolopyrimidine.

4-(Dimethylamino)-1-((4-nitrophenyl)sulfonyl)pyridin-1-ium chloride ([DMAPNS]⁺Cl⁻) has been designed based on DFT studies to have higher reactivity coupled with better stability than that of [DMAPTS]⁺Cl⁻. Accordingly, this novel reagent was prepared by using 1.0 equivalent of p-nitrobenzene sulfonyl chloride (1), 1.0 equivalent of DMAP (2) with higher yield (>99%), using sustainable approaches. The following greener techniques were optimized in the preparation of the novel reagent (i) less hazardous method (3^rd principle of green chemistry), (ii) bio renewable (7^th principle of green chemistry), 2-MeTHF solvent (Class 3 solvent), (iii) room temperature (6^th principle of green chemistry), and (iv) column chromatography free methods (4^th principle of green chemistry). Graphical Abstract