Thermochemistry of aqueous solutions of alkylated nucleic acid bases

Aqueous solutions of pyrimidine nucleic acid bases. Solute-solvent interactions

“…The experimental enthalpies of solution ⌬ sol H m , enthalpies of sublimation ⌬ sub H m , partial molar volumes V 2 Њ and partial molar heat capacities CЊ p,2 reported earlier [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] [7], VЊ 2 [6], ⌬HЊ sol [9]); 20. 1,3-dimethyl-5-butyl (CЊ p,2 [7]), VЊ 2 [6], ⌬HЊ sol [9] [7], VЊ 2 [7], ⌬HЊ sol [8]); 25.…”

“…In the case of the series of 1,3-dimethyl-5-alkyluracils (6,17,19,20) [5,6,19], 1,6-dimethyl-3-alkyluracils (7,(24)(25)(26) [8,11] and 1,3-dimethyl-6-alkyluracils (10,21-23) [5,11] erratic changes were observed to occur in the values of the enthalpy of hydration. The higher values of the enthalpy increment correspond to the odd number of CH 3 groups added while the lower values correspond to those with the even n CH 2 number.…”

“…Substitution of the hydrogen atom by a methyl group on the C(5) or C(6) ring carbon atom of the skeleton, i.e. on the apolar side of the uracil ring, results in contribution to the enthalpy of hydration the average value of which is equal to 9.8 kJ/mol [5], and is practically equal to that obtained for aliphatic hydrocarbons [23]. The contribution of methyl group at an amide N-ring nitrogen N(1), N(3) on the uracil skeleton brings about reduction of ⌬ hydr H m with the mean increment close to ¹2 kJ/ mol.…”

Topochemical polymerization using bis-thyminyl monomers

“…: 111.9 C. MS (ESI) + : calcd for C 23 H 32 N 4 O 8 : m/z 492.2; found: m/z 515.1 (M + Na) + . 1 H NMR (400 MHz, D 6 -DMSO): 13 C NMR (100 MHz, CDCl 3 ): d C 13.0 (C5-CH 3 ), 24 (11.38, 11.34). (7).…”