Nobuo Ohno

Preparation of optically active 1-acetoxy-2-aryloxypropionitriles and its application to a facile synthesis of (S)-(−)-propranolol

Abstract (S)-1-acetoxy-2-aryloxypropionitriles were synthesized by an asymmetric hydrolysis of the racemates with an enzyme. (S)-propranolol, a typical β-adrenergic blocker, was synthesized from (S)-1-acetoxy-2-α-naphthyloxypropionitrile in two steps.

Sesquiterpene lactones and diterpenoids from Helianthus argophyllus

Abstract Three germacranolide sesquitepene lactones (argophyllin-A and -B and eupatolide), three diterpenoids (ciliaric acid, (−)-16-α-hydroxy-kaur-11-en-19-oic acid and (−)-16-α-hydroxykaurane) and one flavonoid (nevadensin) were isolated and characterized from a chloroform extract of Helianthus argophyllus. Argophyllin-A and -B are both described here for the first time. Their structures were deduced by 1H NMR and 13C NMR. Argophyllin-A and -B were found to show anti-auxin effects while eupatolide exhibited weak insecticidal activity.

A polyhalogenated insecticidal monoterpene from the red alga, Plocamium telfairiae

Abstract A new polyhalogenated insecticidal monoterpene was isolated from the red alga, Plocamium telfairiae . Its structure was elucidated by NOE difference spectrum (NOED) analysis. This compound exhibited strong insecticidal activity against mosquito larvae ( Culex pipiens pallens ).

Trichoclin, a new furocoumarin from trichocline incana

Abstract The structure for trichoclin, ( E )-8-(3-methyl-4-hydroxy-2-butenyloxy)-psoralen, a new furocoumarin isolated from Trichocline incana , has been established. Phellopterin and isopimpinellin were also obtained. The new side chain of trichoclin was confirmed by synthesis.

Three sesquiterpene lactones from Helianthus niveus subsp. canescens and H. argophyllus

Abstract Further investigation of the minor terpenoids in Helianthus niveus subsp. canescens and H. argophyllus afforded two known 12,8-fused sesquiterpene lactones, 3-acetylchamissonin and simsiolide as well as one new germacranolide, argophyllin C. Identification and structure elucidation of these lactones by 1 H NMR and chemical transformations are described.