Nucleic Acid Related Compounds. 107. Efficient Nitration of Uracil Base and Nucleoside Derivatives¹

Characteristic Effects of 4,5-Disubstituted Pyridazin-3-one Derivatives with Various Functional Groups: Ab initio Study

“…The other isomers formed by the bond formations of (N1-H and N1-NO 2 ) between the N1 atom of the derivative anions and the substituent groups (H + , NO 2 + ) are also optimized as stable. The bond lengths of (N1-H and N1-NO 2 ) at [R (1)(2) and R (5)(6) ] are shorter than any of the others, while the bond lengths of (N1-H and N1-NO 2 ) at [R (2)(3) , R (3)(4) , and R (4)(5) ] are longer than any of the others.…”

“…To investigate the structural and electronic effects induced by the donating/ withdrawing groups of the functional and substituent groups, the summations of two hammett substitutent constants are scaled on the X-axis. 27 Due to the change from the electron donating group of OMe to the electron withdrawing group of NO 2 , the variations in the lengths of R (1)(2) , R (2)(3) , and R (3)(4) increase, and the variations of R (4)(5) and R (5)(6) decrease. Due to the change in the substituent groups (Y), the bond length of (1.26~1.36 Å) at R (1)(2) is shorter than the others, while the bond length of (1.4~1.48 Å) at R (3)(4) is the longest.…”

“…Therefore, the derivative anions without the substituent groups are optimized as stable structures. At the five bond lengths of [R (1)(2) , R (2)(3) , R (3)(4) , R (4)(5) , R (5)(6) ], the variations of the bond length of the derivative anions without the substituent (Y) groups are more linear than the others. These bond lengths are closer to that of the double bond of (R (C-C) = 1.34 Å).…”

“…Since pyridazine nucleosides were recognized as having biological activity 1,2 and as being useful as synthetic auxiliary materials, 3,4 many studies have focused on their synthesis [5][6][7][8][9][10][11][12][13][14][15] and applications. [16][17][18][19][20][21] Particularly, much effort has been made to develop convenient and efficient routes for their synthesis.…”

Synthesis of alkyl 6‐methyl‐4‐(2‐trifluoromethylphenyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates possessing a N‐3 nitro substituent to determine calcium channel modulation structure‐activity relationships

“…Thus, the acid catalyzed condensation of 2-trifluoromethyl-benzaldehyde (1), urea (2) and an alkyl acetoacetate (3) in MeOH at 85-87° for 8 hours afforded the respective product (4-7) in 27-50% yield. Nitration of the alkyl esters (4-7) using Cu(NO 3 ) 2 •3H 2 O and Ac 2 O [12], following a procedure similar to that used for the preparation of 1-methyl-3-nitrouracil [13], furnished the respective alkyl 6-methyl-3-nitro-4-(2-trifluoromethylphenyl)-1,2,3,4-tetrahydro-2H-pyrimidine-2-one-5-carboxylate (8-11) in 35-51% yield.…”