Aporphines. 31. Synthesis and antitumor activity of aporphine nitrogen mustards.

A series of aporphine nitrogen mustards and their congeners (1b-g) has been prepared. N-[[Bis(2-chloroethyl)-amino]-2,11-dihyroxy-10-methoxynoraporphine (1b) and its mono- and diacetyl ester derivatives (1c-d) were prepared from N-(chloroacetyl)-2,11-diacetoxy-10-methoxynoraporphine (2). Reaction of 2 with diethanolamine under various conditions and different solvents resulted in the corresponding N-[[bis(2-hydroxyethyl)amino]acetyl] precursors, which were subsequently treated with SOCl2 to yield the target compounds. N-(2-Choroethyl)norapocodeine (1e) was obtained from the chlorination of N-(2-hydroxyethyl)norapocodeine (9) with SOCl2. Prolonging such treatment was found to result in the formation of N-[2-(chloroethoxy)ethyl]norapocodeine (1f) at the expense of 1e. N-[[[N'-(2-Chloroethyl)carbamyl]oxy]ethyl]norapocodeine (1g) and its 11-(2-chloroethyl)carbamyl derivative (1h) were also prepared. All the double-armed aporphine amide nitrogen mustards (ab-d) were found to have antitumor activity. The single-armed aporphine nitrogen mustard (1e) was also active in P388 but the activity was less than that observed with 1b-d. The lead compound 1a was inactive in the LE1210 and P388 systems at the doses tested. Similarly, the two aporphine mustard congeners (1f,g) were also inactive in the P388 system. All the activity was observed in the intraperitoneally innoculated tumor systems.

Aporphines. 34. (-)-2,10,11-Trihydroxy-N-n-propylnoraporphine, a novel dopaminergic aporphine alkaloid with anticonvulsant activity.

(-)-2,10,11-Trihydroxy-N-n-propylnoraporphine (TNPA,2c) has been synthesized from thebaine (3a), via northebaine (3b), normorphothebaine (2a), and alkylation to the N-propyl derivative 2b. O-Demethylation gave the desired product 2c. Compound 2c showed activity comparable to its 10,11-dihyroxy counterpart (NPA, 1b) on the stimulation of dopamine-sensitive adenylate cyclase in carp retinal homogenates. The evaluation of 2c on audiogenic seizures in mice, in the protection against paroxysimal EEG and myoclonic response to photic stimulation in the baboon, revealed a similar pharmacological profile in comparison to NPA and apomorphine, with TNPA showing a prolonged duration of action in abolishing myoclonic response to photic stimulation in the baboon.

Rigid analogues of dopamine: synthesis and interaction of 6-exo- and 6-endo-(3',4'-dihydroxyphenyl)-2-azabicyclo[2.2.2]octanes with dopamine uptake sites and receptors.

Two isomeric 6-endo- and 6-exo-(3',4'-dihydroxyphenyl) derivatives (1 and 2) of 2-azabicyclo[2.2.2]octane were synthesized as semirigid analogues of dopamine (DA) to help evaluate the preferred conformation of dopamine at the uptake site of the presynaptic nerve terminal and at the DA receptor. Against the uptake of 0.1 microM [3H]DA by a synaptosomal preparation of corpus striatum from the reserpine-pretreated rat, 2 was found to have a weak inhibitory effect that was three times greater than that of 1 (IC50 = 32 vs. 110 microM). Interactions with DA receptors were assessed with competition for binding of [3H]apomorphine (APO) and on the effect on DA-sensitive adenylate cyclase. Compounds 1 and 2 were both virtually inactive against the binding of 0.5 nM [3H]APO at a screening concentration of 100 microM. The experimental compounds also exhibited only slight adenylate cyclase stimulation in rat striatal homogenates, with 1 appearing to be somewhat more active (at 50 or 400 microM). The weak activities of 1 and 2 and their relatively small differences in activity in these test systems suggest that the DA analogues interact only weakly with the DA transport and receptor sites, possibly as a result of the steric interference caused by the bulky bicyclic ring.

Aporphines, 36. Dopamine receptor interactions of trihydroxyaporphines. Synthesis, radioreceptor binding, and striatal adenylate cyclase stimulation of 2,10,11-trihydroxyaporphines in comparison with other hydroxylated aporphines.

The presence of the A ring of aporphines and the addition of substituents to it and to other portions of the aporphine ring systems can extend explorations of the dimensions and other characteristics of the dopamine receptors. Accordingly, the synthesis and some physical and pharmacological properties of a series of (-)-2,10,11-trihydroxyaporphines (3a-g) are described. Structure-activity relationships among mono-, di-, and trihydroxyaporphines were evaluated against the high-affinity (nanomolar) binding of [3H]apomorphine (APO) and [3H]spiroperidol (SPR) with a subcellular fraction (P4) of caudate nucleus from bovine brain. In addition, DA-sensitive adenylate cyclase activity was evaluated in homogenates of rat brain striatal tissue. The rank order of displacement of [3H]APO by potent aporphines (IC50 less than or equal to 30 nM) correlated approximately with their ability to stimulate cyclic AMP synthesis. Potency orders against two ligands were dissimilar; for example, increasing the size of N6-alkyl substituents increased potency vs. [3H]SPR but not vs. [3H]APO binding. Moreover, [3H]SPR binding correlated poorly with cyclase activity or [3H]APO binding, suggesting a closer relationship of [3H]APO binding to dopamine-sensitive adenylate cyclase activity.

Oligonucleotide sequencing using guanine-specific methylation and electrospray ionization ion trap mass spectrometry.

This paper describes a novel method to map guanine bases in short oligonucleotides using a simple chemical modification reaction and subsequent analysis by electrospray ionization ion trap mass spectrometry (ITMS). In situ guanine-specific methylation followed by gas-phase fragmentation permits the determination of the positions of all guanine residues. Collision-induced dissociation (CID) of the monomethylated oligonucleotide strand promotes rapid depurination and further collision (MS3) of the apurinic oligonucleotide leads to preferential cleavage of the backbone at the site of depurination. The mass of the resulting complementary product ions verifies the position of each guanine base in the sequence. The utility of this methodology is demonstrated for oligonucleotide sequences up to 10 bases in length. In addition, this technique successfully illustrates the use of selective fragmentation for sequencing oligonucleotides by ITMS.

Chloroethylnorapomorphine, a proposed long-acting dopamine antagonist: interactions with dopamine receptors of mammalian forebrain in vitro.

N-Chloroethylnorapomorphine (NCA) interacts with homogenates of rat corpus striatum to block subsequent stimulation of cyclic AMP synthesis by 50 micro M dopamine (DA) (IC50 30 micro M). The 10-O-methylated (11-monophenolic) analog of NCA is weaker; an O,O'-diester of NCA is inactive. The NCA-induced inhibition is counteracted by coincubation with DA or apomorphine, but not norepinephrine. Blockade by NCA is non-competitive vs. DA and not readily reversed by washing. NCA also competes for binding of 3H-apomorphine to subsynaptosomal calf caudate membranes (IC50 285 nM) with greater potency than the monophenolic or diester analogs. NCA may represent a unique long-acting antagonist of DA receptors.

Evaluation of 2-azabicyclo[2.2..2]octane analogs of 4-anilidopiperidine analgesics.

Eight analogs of the fentanyl-type analgesics, in which the piperidine ring is restricted into a boat conformation, were evaluated for analgesic activity. All analogs were less active than fentanyl, but interesting conformational and structural relationships were observed. Results of the study are discussed.

Synthesis of 5,6-benzo-2-azabicyclo[2.2.2]octane derivatives as potential benzomorphan-type analgesic agents.

The synthesis of two N-substituted 5,6-benzo-2-azabicyclo[2.2.2]octane analogs of benzomorphan-type analgesics via benzyne addition to appropriate N-substituted N-alkyl-2-pyridones is described. Neither derivative possessed observable analgesic activity at the doses tested.

Effect of cooking on the nitrate levels in vegetables.

The effects on the nitrate content of vegetables exposed to boiling in water for various lengths of time is described. Whilst certain cultivars show a steady decrease in nitrate levels, other varieties show an initial rise. The nitrate content of the cooking water used shows a sustained increase as the cooking time is extended.

Nitrate in vegetables: estimation by HPLC.

Over the past fifty years the development of high-tech farming has led to excessive amounts of fertiliser being applied to soil. Some research aspects of this abuse are described in relation to the uptake of nitrate into vegetables. In order to monitor this problem a high precision HPLC method capable of rapid throughput has been evolved. Using this HPLC method the results over a twelve month period are presented and compared with the existing standards now legally enforced in Switzerland and Holland.

Novel poly-substituted aryl acridinium esters and their use in immunoassay.

A new series of stable acridinium ester conjugates have been developed for use as non-isotopic labels in immunoassay. They have proved to be a flexible alternative to radioimmunoassay. We present data showing the successful development of immunoassays in sandwich, competitive and receptor formats. In addition, hydrophilic acridinium ester analogues have been synthesized, encapsulated in liposomes, and utilized as labels in immunoassay. The potential of this technology is discussed.

A chemiluminescent immunoassay for urinary thromboxane B2.

Because of the vasoactive properties of thromboxane A2 and other related prostaglandins, much research has been conducted on drugs which alter their levels. Urinary levels of thromboxane B2 and 2,3-dinor thromboxane B2 (major urinary metabolite of thromboxane B2) are used as an indication of thromboxane production in-vivo. In order to accurately measure urinary TXB2 levels of subjects on investigative drugs which lower TXA2 and subsequently TXB2, a simple and sensitive analytical tool becomes necessary. We have thus developed a non-radioisotopic (chemiluminescent) assay for urinary TXB2. Sensitivity has been demonstrated to 5 pg/ml. The method correlates well with gas chromatography/mass spectrometry (the accepted reference method) even without column chromatographic purification prior to the conduct of the chemiluminescent assay (r = 0.96). In addition, we have demonstrated feasibility for a chemiluminescent assay to measure urinary 2,3-dinor TXB2.

(-)N-(chloroethyl)norapomorphine inhibits striatal dopamine function via irreversible receptor binding.

beta-Haloalkylamine derivatives such as phenoxybenzamine are thought to irreversibly inactivate noradrenaline receptors by a process involving the formation of a reactive ethyleneimmonium cation which is followed by ring scission yielding the reactive carbonium ion which can then react further with a nucleophilic centre located on the receptor. Further study of catecholamine function has awaited the development of similar agents which can alkylate the dopamine receptor. We report here on the structure (Fig. 1) and evaluation of one agent with such potential, (--)N-(chloroethyl)norapomorphine [(--)NCA], and that this compound may be of significant value as a pharmacological and biochemical probe of the dopamine receptor.