Molecular Structure of Heterocycles: 2^#

^#For Part 1, see Ref. 1.

NMR Spectroscopy, X- ray Diffraction, and Semiempirical MO Calculations of 5-Bromo-4, 6-dimethoxy-4-trichloromethyl-hexahydropyrimidin-2-one.

Abstract

The structure of 5-Bromo-4, 6-dimethoxy-4-(trichloromethyl)hexahydro 2-pyrimidinone (3), synthesized from the reaction of 4-methoxy-4-(trichloromethyl)tetrahydro-2-pyrimidinone (2) with bromo and methanol, was determined by nmr spectroscopy, X-ray diffraction, and semiempirical MO calculations.

¹H and ¹³C nmr data shown that only one pair of the diastereoisomers was obtained. The AM1 calculations showed that 3a is the more stable diastereoisomers pair. The x-ray diffraction data confirmed that only the structure 3a (4S5S6R/4R5R6S) of compound 3 was obtained. Compound 3a (C₇H₁₀BrCl₃N₂O₃, M_r = 356.43) crystallizes in the orthorhombic space group P2₁2₁2₁ with the unit cell dimensions a = 7.112(2), b = 14.719(2) and c = 12.084(3) Å, R = 7.32 % and wR₂ = 14.92 % for an F ² refinement on unique data with 2931 reflections collected and 2248 independent (R_int = 4.01%), Flack parameter 0.00(3).

^#For Part 1, see Ref. 1.

Key Words:

• Pyrimidin-2-ones
• NMR
• X-ray Structure Investigation
• MO calculations
• AM1

Notes

^#For Part 1, see Ref. 1.