38762-37-7Relevant academic research and scientific papers
Theoretical, structural, vibrational, NMR, and thermal evidence of the inter- versus intramolecular hydrogen bonding in oxamides and thiooxamides
Desseyn,Perlepes,Clou,Blaton,Van Der Veken,Dommisse,Hansen
, p. 5175 - 5182 (2007/10/03)
This contribution describes the study of hydrogen bonding in secondary oxamides, monothiooxamides, and dithiooxamides by ab initio calculations, X-ray diffractions, NMR spectra, thermal analysis, and variable-temperature infrared and Raman spectroscopy. The results can all be interpreted as a function of the change in the strength and the nature of the hydrogen bonding by substituting oxygen for sulfur in the series CH3-HNCOCONHCH3, CH 3HNCSCONHCH3, CH3HNCSCSNHCH3 and by changing the steric influence of the alkyl group in a series of oxamides (RHNCOCNHR; R = CH3, C2H5, iC3H 7, tC49).
Dihydropiperazine neonicotinoid compounds. Synthesis and insecticidal activity
Samaritoni, Jack G.,Demeter, David A.,Gifford, James M.,Watson, Gerald B.,Kempe, Margaret S.,Bruce, Timothy J.
, p. 3035 - 3042 (2007/10/03)
Syntheses of various isomeric dihydropiperazines can be approached successfully by taking advantage of the regioselective monothionation of their respective diones. Preparation of the precursor unsymmetrical N-substituted piperazinediones from readily available diamines is key to this selectivity. The dihydropiperazine ring system, as exemplified in 1-[(6-chloropyridin-3-yl)methyl]-4-methyl-3-oxopiperazin-2-ylidenecyanamide (4) and 1-[(2-chloro-1,3-thiazol-5-yl)methyl]-4-methyl-3-oxopiperazin-2- ylidenecyanamide (25), has been shown to be a suitable bioisosteric replacement for the imidazolidine ring system contained in neonicotinoid compounds. However, placement of the cyanoimino electron-withdrawing group further removed from the pyridine ring, as in 4-[(6-chloropyridin-3-yl)methyl]-3-oxopiperazin-2-ylidenecyanamide (3a), or relocation of the carbonyl group, as in 1-[(6-chloropyridin-3-yl)methyl]-4-methyl-5-oxopiperazin-2-ylidenecyanamide (5), results in significantly decreased bioisosterism. The dihydropiperazine ring system of 4 and 25 also lends a degree of rigidity to the molecule that is not offered by the inactive acyclic counterpart 2-[(6-chloropyridin-3-yl)-methyl-(methyl)amino]-2-(cyanoimino)-N, N-dimethylacetamide (6). A pharmacophore model is proposed that qualitatively explains the results on the basis of good overlap of the key pharmacophore elements of 4 and imidacloprid (1); the less active regioisomers of 4 (3a, 5, and 6) feature a smaller degree of overlap.
