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Synthesis and in Vitro Antifungal Activity against Botrytis cinerea of Geranylated Phenols and Their Phenyl Acetate Derivatives.

Chávez MI, Soto M, Taborga L, Díaz K, Olea AF, Bay C, Peña-Cortés H, Espinoza L - Int J Mol Sci (2015)

Bottom Line: The effect of solvent on yields and product distribution is discussed.For monomethoxyphenols the reaction gives better yields when acetonitrile is used as a solvent and AgNO3 is used as a secondary catalyst.However, for di- and trimethoxyphenols the reaction proceeds only in dioxane.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química, Universidad Técnica Federico Santa María, Valparaíso 2340000, Chile. maria.chavez@usm.cl.

ABSTRACT
The inhibitory effects on the mycelial growth of plant pathogen Botritys cinerea have been evaluated for a series of geranylphenols substituted with one, two and three methoxy groups in the aromatic ring. The results show that the antifungal activity depends on the structure of the geranylphenols, increasing from 40% to 90% by increasing the number of methoxy groups. On the other hand, the acetylation of the -OH group induces a change of activity that depends on the number of methoxy groups. The biological activity of digeranyl derivatives is lower than that exhibited by the respective monogeranyl compound. All tested geranylphenols have been synthesized by direct coupling of geraniol and the respective phenol. The effect of solvent on yields and product distribution is discussed. For monomethoxyphenols the reaction gives better yields when acetonitrile is used as a solvent and AgNO3 is used as a secondary catalyst. However, for di- and trimethoxyphenols the reaction proceeds only in dioxane.

No MeSH data available.


Main correlations observed for compound 15, selective 1D NOESY (4a), and 2D1H–13C HMBC (4b).
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ijms-16-19130-f004: Main correlations observed for compound 15, selective 1D NOESY (4a), and 2D1H–13C HMBC (4b).

Mentions: Compound 15: In the 1H NMR spectrum a single hydrogen aromatic signal was observed at δH = 6.42 ppm (s, 1H), confirming the aromatic disubstitution pattern. The positions of geranyl chains on the aromatic ring were established by selective one-dimensional (1D) NOESY experiments, wherein the aromatic signal at δH = 6.42 ppm assigned to H-5 showed spatial correlations with two singlets at 3.87 and 3.77 ppm, assigned to CH3O-C6 and CH3O-C4 (by 2D HSQC and HMBC), respectively. In addition, the signal at δH = 3.39 ppm (d, J = 6.0 Hz, 2H) assigned to hydrogen H-1ʹ showed spatial correlations with the signals at δH = 5.31 (s, 1H) and δH = 1.76 ppm (s, 3H), assigned to OH and CH3-C3ʹ, respectively. The signal at δH = 3.31 ppm (d, J = 6.0 Hz, 2H) assigned to hydrogen H-1ʹʹ showed spatial correlations with CH3O-C4 and with δH = 1.74 ppm (s, 3H) assigned to CH3-C3ʹʹ. Ortho aromatic disubstitution of both geranyl chains was confirmed by the observation of spatial NOE interaction between hydrogen H-1ʹ and H-1ʹʹ (see Figure 4a). Finally, the complete structural determination was established by heteronuclear 2D HSQC and 2D HMBC correlations, where H-1ʹ showed 3JH–C coupling with C-3 (δC = 122.1 ppm), C-3ʹ (δC = 135.2 ppm) and C-1 (δC = 137.9 ppm) and 2JH–C coupling with C-2 and C-2ʹ (δC = 127.3 and 123.8 ppm, respectively). H-1ʹʹ showed 3JH–C coupling with C-4 (δC = 150.7 ppm), C-3ʹʹ (δC = 134.4 ppm) and C-2 (δC = 127.3 ppm) and 2JH–C coupling with C-2ʹʹ and C-3 (δC = 122.8 and 122.1 ppm, respectively). The signal of H-5 at δH = 6.42 ppm (s, 1H-Ar) showed3JH–C coupling with C-3 and C-1 (δC = 122.1 and 137.9 ppm, respectively) and 2JH–C coupling with C-6 and C-4 (δC = 144.4 and 150.7 ppm, respectively). These and other heteronuclear correlations are shown in Figure 4b.


Synthesis and in Vitro Antifungal Activity against Botrytis cinerea of Geranylated Phenols and Their Phenyl Acetate Derivatives.

Chávez MI, Soto M, Taborga L, Díaz K, Olea AF, Bay C, Peña-Cortés H, Espinoza L - Int J Mol Sci (2015)

Main correlations observed for compound 15, selective 1D NOESY (4a), and 2D1H–13C HMBC (4b).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581290&req=5

ijms-16-19130-f004: Main correlations observed for compound 15, selective 1D NOESY (4a), and 2D1H–13C HMBC (4b).
Mentions: Compound 15: In the 1H NMR spectrum a single hydrogen aromatic signal was observed at δH = 6.42 ppm (s, 1H), confirming the aromatic disubstitution pattern. The positions of geranyl chains on the aromatic ring were established by selective one-dimensional (1D) NOESY experiments, wherein the aromatic signal at δH = 6.42 ppm assigned to H-5 showed spatial correlations with two singlets at 3.87 and 3.77 ppm, assigned to CH3O-C6 and CH3O-C4 (by 2D HSQC and HMBC), respectively. In addition, the signal at δH = 3.39 ppm (d, J = 6.0 Hz, 2H) assigned to hydrogen H-1ʹ showed spatial correlations with the signals at δH = 5.31 (s, 1H) and δH = 1.76 ppm (s, 3H), assigned to OH and CH3-C3ʹ, respectively. The signal at δH = 3.31 ppm (d, J = 6.0 Hz, 2H) assigned to hydrogen H-1ʹʹ showed spatial correlations with CH3O-C4 and with δH = 1.74 ppm (s, 3H) assigned to CH3-C3ʹʹ. Ortho aromatic disubstitution of both geranyl chains was confirmed by the observation of spatial NOE interaction between hydrogen H-1ʹ and H-1ʹʹ (see Figure 4a). Finally, the complete structural determination was established by heteronuclear 2D HSQC and 2D HMBC correlations, where H-1ʹ showed 3JH–C coupling with C-3 (δC = 122.1 ppm), C-3ʹ (δC = 135.2 ppm) and C-1 (δC = 137.9 ppm) and 2JH–C coupling with C-2 and C-2ʹ (δC = 127.3 and 123.8 ppm, respectively). H-1ʹʹ showed 3JH–C coupling with C-4 (δC = 150.7 ppm), C-3ʹʹ (δC = 134.4 ppm) and C-2 (δC = 127.3 ppm) and 2JH–C coupling with C-2ʹʹ and C-3 (δC = 122.8 and 122.1 ppm, respectively). The signal of H-5 at δH = 6.42 ppm (s, 1H-Ar) showed3JH–C coupling with C-3 and C-1 (δC = 122.1 and 137.9 ppm, respectively) and 2JH–C coupling with C-6 and C-4 (δC = 144.4 and 150.7 ppm, respectively). These and other heteronuclear correlations are shown in Figure 4b.

Bottom Line: The effect of solvent on yields and product distribution is discussed.For monomethoxyphenols the reaction gives better yields when acetonitrile is used as a solvent and AgNO3 is used as a secondary catalyst.However, for di- and trimethoxyphenols the reaction proceeds only in dioxane.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química, Universidad Técnica Federico Santa María, Valparaíso 2340000, Chile. maria.chavez@usm.cl.

ABSTRACT
The inhibitory effects on the mycelial growth of plant pathogen Botritys cinerea have been evaluated for a series of geranylphenols substituted with one, two and three methoxy groups in the aromatic ring. The results show that the antifungal activity depends on the structure of the geranylphenols, increasing from 40% to 90% by increasing the number of methoxy groups. On the other hand, the acetylation of the -OH group induces a change of activity that depends on the number of methoxy groups. The biological activity of digeranyl derivatives is lower than that exhibited by the respective monogeranyl compound. All tested geranylphenols have been synthesized by direct coupling of geraniol and the respective phenol. The effect of solvent on yields and product distribution is discussed. For monomethoxyphenols the reaction gives better yields when acetonitrile is used as a solvent and AgNO3 is used as a secondary catalyst. However, for di- and trimethoxyphenols the reaction proceeds only in dioxane.

No MeSH data available.