Plant Growth Suppressive Activity of (R)-3-(7′-Aryl-9′-hydroxyprop-8′-yl)coumarin, Structural Isomer of Z-2-Hydroxybenzylidene-γ-butyrolactone-type Lignan

Abstract

3-(7′-Aryl-9′-hydroxyprop-8′-yl)­coumarin, which is a structural isomer of a Z-2-hydroxybenzylidene-γ-butyrolactone-type lignan, was stereoselectively synthesized and subjected to plant growth regulation examination. (R)-4′-Methoxyphenyl derivative 3 showed stereospecific plant growth suppressive activity. The significance of the presence of hydroxy group at the 9′-position for the activity was clarified. The effect of the substituent at the 7′-aryl group was also shown. The 3′-methoxy, 4′-methoxy, and 4′-trifluoromethyl derivatives 10, 3, and 22 led to the most significant growth suppression of Italian ryegrass roots. The 2′-methoxy derivative 9 and 4′-methoxy derivative 3 provided the most growth suppressive activity against lettuce shoots and roots, respectively.

Regiospecific and Enantiospecific Effects of the β-Benzyl-α-benzylidene-γ-butyrolactone Structure on Phytotoxic Fungi

“…The chemical shift of the Ebenzylidene olefinic proton of 10 resonated at a lower field (7.98 ppm) than the Z-benzylidene olefinic proton of 8 (7.45 ppm). 11,14 The NOE between the synthesized E-benzylidene olefinic proton and the benzylic proton was not observed. The E-2-butoxybenzylidene 11 was prepared from 9.…”

“…Table illustrates the preliminary analysis of the antifungal properties of E -, Z -, R -, and S -forms of benzylidene compounds and R - and S - forms of coumarin compounds. The coumarin compounds 7 , ent - 7 , Z -2-methoxybenzylidene 8 , ent - 8 , E -phenolic benzylidene 9 , and ent - 9 have been obtained in previous work . The E -2-methoxybenzylidene 10 and ent - 10 were prepared by methylation using CH 3 I and Ag 2 O from phenol 9 and ent - 9 , respectively.…”

“…The numbering of compounds follows the IUPAC rule for lignans . Coumarin 7 , ent - 7 and benzylidene 8 , ent - 8 , 9 , and ent - 9 were obtained in the previous experiment . The starting 3-(4-methoxybenzyl)-4-butanolide, I-1 , I-2 , and I-3 , were also prepared by the previously described stereoselective asymmetric synthetic method or the modified method …”

“…17 7 and benzylidene 8, ent-8, 9, and ent-9 were obtained in the previous experiment. 14 The starting 3-(4-methoxybenzyl)-4-butanolide, I-1, I-2, and I-3, were also prepared by the previously described stereoselective asymmetric synthetic method or the modified method. 14 General Procedure for E-2-Methoxy Compounds.…”

“…Z -Benzylidene 2 could be obtained from 3-(7′-aryl-9′-hydroxyprop-8′-yl)­coumarin 1 through the trans-lactonization. In our previous study, the synthetic methods of 3-(7′-aryl-9′-hydroxyprop-8′-yl)­coumarin 1 and E / Z -β-benzyl-α-2-hydroxybenzylidene-γ-butyrolactone 2 and 3 were estimated, leading to the discovery of the enantiospecific suppression of plant growth caused by 3-(7′-aryl-9′-hydroxyprop-8′-yl)­coumarin 1 . In the pharmaceutical research, phenprocoumon bearing a bond between the 3-position of the coumarin structure and the 7′-position of phenylpropanoid has been known as a vitamin K antagonist .…”