Susumu Kanno

Cyclization of polyenes: VI. Biogenetic-type synthesis of levantenolides isolated from Turkish tobacco☆

Abstract Keto acid (VII) was assumed to be a precursor in the biogenesis of levantenolides (IV and V). The syntheses of the analogous compounds (IX and X) and their cyclization to IV and V were carried out as follows. Reaction of farnesyl bromide (XV and XX) with 2,2′-di-3-methylfurylmercury afforded the corresponding furano derivatives (XVI and XXI), which were photo-oxidized to butenolide derivatives (IX and X). Biogenetic-type cyclization of IX and X with stannic chloride afforded IV, V, and XIX in moderate yields.

Cyclization of polyenes—V : Synthesis of α-chamigrene by the cyclization of cis- and trans-monocyclofarnesols☆

Abstract Trans-Monocyclofarnesic acid (IXa) was obtained from dihydro-β-ionone (X) and triethyl phosphono-acetate in moderate yield. Cis-Monocyclofarnesic acid (IXb) was separated from the mixture of the Wittig reaction. Cyclization of both cis- and trans-monocyclofarnesols with iodine afforded α chamigrene (V).

Extrinsic plasmalogens suppress neuronal apoptosis in mouse neuroblastoma Neuro-2A cells: importance of plasmalogen molecular species

The level of ethanolamine plasmalogen (Pls), a phospholipid with antioxidant activity, is known to decrease in the brains of patients suffering from Alzheimers disease (AD). The present study was performed to determine the mechanism underlying the neuroprotective effect of Pls. Neuronal apoptosis induced by serum starvation was suppressed by Pls in a concentration-dependent manner. Pls also induced the suppression of p53 and cytochrome c expression, which was increased due to serum starvation. Further, the activation of apoptosis signal-regulating kinase 1 (ASK 1) was also inhibited by Pls. Among the phospholipids analyzed, only Pls displayed an antiapoptotic effect. Pls also inhibited the reduction of cellular phospholipid and 20:4 levels. These functions underlying the action of Pls may be responsible for the regulation of membrane functions and second messenger production. In addition, of the species investigated, Pls with 22:6 (DHA) displayed the strongest suppression of neuronal apoptosis; however, no significant differences in reactive oxygen species (ROS) scavenging activity was observed between various species of Pls. Overall, our results show the potential of Pls, especially those containing DHA, in the prevention of AD.

The acid-catalysed cyclisation of polyolefins. Part IV. The cyclisation of β-monocyclofarnesic acid

Cyclisation of β-monocyclofarnesic acid (I) with gaseous boron trifluoride in benzene solution affords a ring-closed acid (III), the structure of which has been elucidated by chemical and physical methods.