Polymeric reagents with propane-1,3-dithiol functions and their precursors for supported organic syntheses

Reliable completely odorless syntheses of soluble copolymeric reagents of styrene type containing propane-1,3-dithiol functions able to convert carbonyl compounds into 1,3-dithiane derivatives and to support other useful transformations are reported together with their progenitor copolymers containing benzenesulfonate or thioacetate groups perfectly stable in open air and suitable for unlimited storage. The effectiveness of the prepared reagents as tools for polymer-supported syntheses to produce ketones by aldehyde umpolung and alkylation is tested in the conversion of benzaldehyde to phenyl n-hexyl ketone starting from copolymers with different contents of active units and molecular weights. To facilitate the adaptation of the prepared soluble copolymeric reagents to other possible applications, a table of solvents and nonsolvents is presented.

Benzylamine-related compounds stimulate rat vas deferens neurotransmission and potentiate memory in the mouse acting as potassium channel blockers.

In stimulated rat vas deferens, the new compound 2, 6-dibutylbenzylamine (B25) and some related benzylamines, first potentiated then completely inhibited electrically-induced twitch response, showing the biphasic effect previously observed in unstimulated preparations. To verify if this effect could be referred to as a modulation of potassium channels the activity of some benzylamines, KCl, tetraetylammonium (TEA), BaCl(2), 4-aminopyridine (4-AP), glibenclamide (GLI), charibdotoxin (ChTX) and apamin (APA) has been compared. While KCl and benzylamine-related derivatives induced biphasic effects, TEA, 4-AP, BaCl(2), GLI stimulated but were unable to inhibit the twitches. The pretreatment with stimulating concentrations of TEA, 4-AP, GLI, APA or ChTX and B25, as reference compound in the benzylamine series, dose-dependently reduced the stimulatory effect of KCl but were unable to modify the inhibitory effect induced by this ion. Both KCl and B25 potentiated each others own inhibitory effect suggesting that, unlike other potassium channel blockers, they could modulate in an opposite way voltage-dependent potassium channels in order to facilitate and then depress neurotransmission. In other experiments, benzylamines, KCl, TEA, 4-AP and GLI reverted the inhibitory effect of cromakalim and omega-conotoxin GVIA (omega-CTX). This effect further supports a common mechanism of action (potassium channel blockade) probably inducing the opening of Ca(2+)channels different from N or L in the preparation. Finally, the prevention of minoxidil-induced amnesia in the mouse by B25 and related benzylamines, comparable to the same effect shown by TEA and 4-AP, indicates that these compounds are endowed with potential pharmacological activity in the CNS as well.

Reaction of pig plasma benzylamine oxidase with beta-aminopropionitrile.

Beta-aminopropionitrile (BAPN) is an inhibitor of pig plasma benzylamine oxidase. BAPN is oxidized by benzylamine oxidase. Inhibition develops in a time-dependent fashion upon incubation of BAPN with the enzyme in the absence of substrate. The product of oxidation of BAPN by benzylamine oxidase, cyanacetaldehyde, was identified and prepared by synthesis. It is an irreversible inhibitor of the enzyme.