Structure-activity relationships in reactivators of organophosphorus-inhibited acetylcholinesterase. 9. N-Heterocyclic acraldoximes methiodides

N-Heterocyclic acraldoximes methiodides, where the heterocyclic residues are 2-, 3-, and 4-pyridyl, 2-(1-methyl)imidazolyl or 4-pyrimidyl, were prepared and tested for their reactivating potency on acetylcholinesterase inhibited from diisopropylphosphorofluoridate (DFP). The in vitro testing revealed that the new compounds are good reactivators of the phosphorylated electric eel cholinesterase. The structure-activity relationships are briefly discussed.

Synthesis and biological activity of some antitumor benzophenanthridinium salts

A facil synthesis of benzophenanthridinium salts has been developed and used for preparing a number of these compounds. The antitumor activities in mouse leukemia L1210 (LE) and P388 (PS) were determined as well as some selected antimicrobial activities. Although antitumor activity was exhibited by several of the derivatives, none was as active as the naturally occurring alkaloid fagaronine. Fagaronine was made available as a synthetic by an improved procedure. Some structure-activity relationships among antitumor benzophenanthridinium salts are discussed.

[Purification of the acetylcholinesterase from human erythrocytes by affinity chromatography (author's transl)]

The acetylcholinesterase from human erythrocytes was released from the plasma membrane with 0.2% Triton X-100 at low ionic strength and purified by two affinity chromatography steps on Sepharose-bound m-[6-(6-amino-caproylamino)caproylamino]phenyltrimethyl-ammonium. The synthesis of the inhibitor is described. The purified, detergent-free acetylcholinesterase was obtained with a specific activity of 4270 U/mg (158000-fold purification) and a 28% yield. The enzyme is a glycoprotein and aggregates in the absence of Triton X-100 into higher molecular complexes. The molecular weight was estimated by sodium dodecylsulfate electrophoresis to be 80000 +/- 3000 in the presence of 2-mercapto-ethanol and 154000 +/- 6000 in its absence.

Cholinergic compounds. V - New synthesis and further pharmacological evaluation of desethermuscarine

Two new methods of syntesis of (+/-)-desethermuscarine (I) are reported along with the pharmacological evaluation of (I) extended to several muscarinic and nicotinic receptors.

Cholinergic compounds. III - Synthesis and biological activity of epi-desmethyldesethermuscarine, desmethyldesethermuscarine and desmethyldesethermuscarone

As a further contribution to better understanding of the nature of the cholinergic receptors, desmethyldesethermuscarone (I), epi-desmethyldesethermuscarine (II a) and desmethyldesethermuscarine (II b) were synthesized. With few exceptions, the drop in muscarinic activity of these compounds compared with that of desethermuscarone and desethermuscarines emphasizes the importance of C-7 methyl (5). As far as nicotinic activity is concerned, C-7 methyl appears much less critical.

High frequency discharge experiment. I: Formation of organic compounds from methane and ammonia

Investigations of the synthesis of organic compounds from methane and ammonia were carried out by using high frequency discharges. The radical of CN was observed in the early phase of the discharge. Therefore it is considered that the CN radical contributes to the successive reaction steps. An important intermediate, a tetramer of hydrogen cyanide was observed to be formed at room temperature. The amounts of this compound progressively increased with time. It was speculated that the purines which were identified in the refluxed sample were synthesized through the above tetramer. Compounds which are thought to be heterocyclic (max:250-265nm) were initially formed in the sample trapped at liquid nitrogen temperature. After hydrolysis with hydrochloric acid, Gly, Asp Ala, etc. were observed in the sample. Overall yield of organic compounds was estimates at 5-6% based on input carbon of methane.

Sterochemical preferences for curarimimetic neuromuscular junction blockade III: enantiomeric bisquaternary amines related to benzoquinonium as probes

Enantiomeric neuromuscular junction blocking agents, which are of the benzoquinonium type but which have a methyl group introduced adjacent to the quaternary moieties to provide an asymmetric center were synthesized and tested to determine whether the neuromuscular junction exhibits the relatively modest (R) greater than (S) superiority shown toward previously tested bisquaternaries. Testing included a mouse inclined screen assay and an in vivo cat hypoglossal nerve-tongue preparation, as well as standard estimations of anticholinesterase activity since the candidate compounds are known to have such a component in their activity spectrum. The observed 2:1 difference in blocking activity favoring the compound with an (R)-configuration is the same as that for previously tested bisquaternaries, both in direction and magnitude. Furthermore, it cannot be accounted for by preferential inhibition of acetylcholinesterase by the (S)-enantiomer. Absolute configurations of the enantiomers were assigned on the basis of comparison with compounds of known configuration.

Preparation and antileukemic activity of some alkoxybenzo(c)phenanthridinium salts and corresponding dihydro derivatives

Salts of 2,3,8,9-tetrasubstituted alkoxy-, hydroxy-, and acetoxybenzo(c)phenanthridines as well as the corresponding 6-methoxy-5,6-dihydrobenzo(c)phenanthridines were prepared from appropriate chalcones through the tetralone and the 4b,10b,11,12-tetrahydrobenzo(c)phenanthridine intermediates. Complete O-demethylation of the tetramethoxybenzophenanthridine was achieved by fusion with pyridine hydrochloride at elevated temperature. The title compounds are active against leukemias L1210 and P388 in mice and some are curative against Lewis lung carcinoma. The importance of the nature of the environment about the nitrogen atom of these compounds and the substituents is discussed. 3,4-Dimethoxy-3,4-methylenedioxychalcone possesses activity against leukemia P388.