Gas-Phase 1H NMR Studies of Internal Rotation Activation Energies and Conformer Stabilities of Asymmetric N,N-Disubstituted Formamides and Trifluoroacetamides
摘要:
Activation parameters and conformational stabilities characterizing the internal rotation about the peptide bond in a series of N,N-asymmetric dialkylformamides (HCONR1R2: R-1 = CH3, R-2 = propyl, butyl, and isopropyl) and N,N-asymmetric dialkyltrifluoroacetamides (F3CCONR1R2: R-1 = CH3, R-2 = propyl, butyl, and isopropyl) are determined from temperature-dependent gas-phase H-1 NMR spectra. Conformer free energy differences, Delta G(298)(0)(syn-anti), in cal mol(-1), and activation free energies, Delta G(298)(double dagger), in kcal mol(-1), for the formamides are -83(14)/19.4(0.1) for R-2 = Propyl, -80(14)/19.3(0.1) for R-2 = butyl, and -91(13)/19.1(0.1) for R-2 = isopropyl and for the trifluoroacetamides 178(24)/16.8(0.1) for R-2 = propyl, 191(53)/16.6(0.1) for R-2 = butyl, and 218(29)/16.3(0.1) for R-2 = isopropyl. The preferred conformer in both the gas and Liquid phases has the N-methyl group syn to the carbonyl oxygen in the formamide systems and the N-methyl group anti to the carbonyl oxygen in the trifluoroacetamides. The gas-phase results are compared to liquid-phase values.
The present invention provides a novel compound having an antiviral action, in particular, an HIV replication inhibiting action, as well as a pharmaceutical composition, in particular, an anti-HIV agent.
wherein, a broken line means the presence or absence of a bond; R
1
is substituted or unsubstituted alkyl etc., R
2
is substituted or unsubstituted alkyloxy etc.; n is 1 or 2; R
3
is a substituted or unsubstituted aromatic carbocyclic group; R
4
is a hydrogen atom etc.; R
5
is a substituted or unsubstituted aromatic carbocyclic group etc.; Y is a single bond etc.; R
6
is substituted or unsubstituted alkyl; R
7
is —Z—R
71
etc.; Z is —NR
72
—CO— etc.; R
71
is substituted or unsubstituted alkyl etc.; R
72
is a hydrogen atom etc.