Crystal and molecular structure of 2,6-dimethyl-3,5-di[N-methyl]-carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate and 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[furan]-1,4-dihydropyridine

The crystal structures of two dihydropyridines were solved by direct method s and refined by full-matrix least-squares procedure. 2,6-Dimethyl-3,5-di[N -methyl]carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate, C3 8H50N6O9 (compound 1): monoclinic, space group P2(1)/c, a = 16.940(2) Angst rom, b = 25.757(3) Angstrom, c = 8.922(1) Angstrom, beta = 93.03(1)degrees, V= 3887.4(8) Angstrom(3), Z = 4 and d(cal) = 1.29 Mg m(-3), R = 0.063 (R-w = 0.071) for 487 parameters and 3394 observations with I greater than or e qual to 3 sigma(I). 2,6-Di-methyl-3,5 -di[N-methyl]-carbamoyl-4-[furan]-1,4 -dihydropyridine C15H19N3O3 (compound 2): triclinic, space group P1, a = 7, 311(1) Angstrom, b = 7.792(1) Angstrom, c = 13.384(2) Angstrom, a = 90.48(6 )degrees, beta = 91.44(6)degrees, gamma = 104.24(7)degrees, V = 738.7(3) An gstrom(3), Z = 4 and d(cal) = 1.30 Mg m(-3), R = 0.062 (R-w = 0.067) for 37 9 parameters and 1751 observations with I greater than or equal to 3 sigma( I). Both compounds crystallize with two molecules in the asymmetric unit. In co mpound 1 these two molecules form a hydrate, thus they can be regarded as a monohydrated dimer, yielding Z = 4 in the unit cell. The dihydropyridine r ings are in shallow boat conformation with C4 substitutions are orientated closely towards the ideal bisection of the dihydropyridine ring. The orient ations of carbamoyl groups at C3 and C5 are synperiplanar and anticlinal in 1; and are anticlinal in 2. The presence of the furan ring in 2, instead o f the aryl ring, affects the orientation of its molecules. In 2, participat ion of the carbamoyl N atom has significantly changed the hydrogen bonding network.