Wagh, Y.B.Kuwar, A.S.Patil, D.R.Tayade, Y.A.Jangale, A.D.Terdale, S.S.Trivedi, D.R.Gallucci, J.Dalal, D.S.2026-02-052015Industrial and Engineering Chemistry Research, 2015, 54, 40, pp. 9675-96828885885https://doi.org/10.1021/acs.iecr.5b01746https://idr.nitk.ac.in/handle/123456789/26203A green and efficient method for the synthesis of newer 2-imino-4-oxothiazolidin-5-ylidene acetate derivatives under catalyst-free conditions by simply stirring symmetrical and unsymmetrical 1,3-diarylthioureas with dialkyl acetylenedicarboxylates in ethanol at room temperature has been developed. Interestingly, the regioselective synthesis affords the 2-imino-4-oxothiazolidin-5-ylidene acetate derivatives: the amine nitrogen bonded to an electron-withdrawing substituent becomes part of the imino component, and the amine nitrogen bonded to an electron-donating substituent becomes the heterocyclic nitrogen. This is the first report wherein the impact of substituents in directing the regiocyclization has been explained and the structure conflict resolved by single-crystal X-ray analysis. © 2015 American Chemical Society.CatalystsCrystal structureCyclizationNitrogenSingle crystalsSynthesis (chemical)X ray analysisAcetate derivativesAmine nitrogenDialkyl acetylenedicarboxylatesElectron-donating substituentsElectron-withdrawing substituentsHeterocyclic nitrogenRegioselective synthesisSingle crystal X-ray analysisRegioselectivity