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Biomedical subjects

H H Ong

Publications and source records attributed to H H Ong.

At least 19 recordsLinked to original sources
PubMed1987

[(6,7-Dichlorobenzo[b]thien-5-yl)oxy]acetic acids and 1,1-dioxides. 1. A structurally novel class of diuretics with hypotensive activity.

A series of [(6,7-dichlorobenzo[b]thien-5-yl)oxy]acetic acids and their corresponding 1,1-dioxides were synthesized and evaluated for diuretic activity in the acute saline loaded mice (ASLM) and hypotensive activity in the spontaneously hypertensive rat (SHR). A significant number of compounds were found to display potent activity in one or both assays, and preliminary structure-activity relationships with respect to each assay were delineated. Compound 94, the 1,1-dioxide of [(6,7-dichloro-2-n-propylbenzo[b]thien-5-yl)oxy]acetic acid was markedly active in both the ASLM and SHR by oral administration. The combined diuretic/hypotensive profile of this compound was further substantiated by its good saluretic response in water loaded conscious dogs and a moderate to good activity in renal hypertensive rats and sinoaortic-deafferented hypertensive dogs.

Acetates↗
PubMed1984

Novel tetracyclic spiropiperidines. 4. Synthesis and pharmacological evaluation of spiro- and 6,7-dihydrospiro[benzo[b]pyrrolo[3,2,1-jk][1,4]benzodiazepine-2 (1H),4'-piperidine]s.

A previously described series of 1-arylspiro[indoline-3,4'-piperidine]s was reported by us to possess significant antidepressant properties. This biological activity was found to be at a maximum among those compounds bearing an ortho substituent (e.g., NH2 as in 1) in the pendant aryl ring. In order to explore further this "ortho effect", we synthesized cyclic analogues of type 3 and 4 in which the position of the o-NH2-substituted aryl group is conformationally restricted and defined. When tested for antidepressant activity by tetrabenazine ptosis prevention in mice, it was found that restriction of rotation of the pendant o-aminophenyl group in these rigid analogues resulted in a loss of antidepressant properties. However, analgesic activity was retained and even improved by this molecular constraint.

Animals↗
PubMed1983

Novel tetracyclic spiropiperidines. 3. 1-arylspiro[indoline-3,4'-piperidine]s as potential antidepressants.

A series of 1-arylspiro[indoline-3,4'-piperidine]s was synthesized and evaluated for potential antidepressant activity by tetrabenazine (TBZ) ptosis prevention and potentiation of 5-hydroxytryptophan (5-HTP) induced head twitching in pargyline-pretreated rats. Marked TBZ activity was observed with analogues bearing an ortho substituent on the pendant aromatic ring, as exemplified by lead compound 25a, 1-(2-chlorophenyl)spiro[indoline-3,4'-piperidine], which was also very active in potentiating 5-HTP stereotypy and yohimbine toxicity, as well as in inhibiting the muricidal behavior in rats. The potent in vivo activity of 25a, coupled with weak to moderate in vitro activity with respect to the blockade of neuronal reuptake of biogenic amines, seems to suggest a profile atypical of tricyclic antidepressants.

5-Hydroxytryptophan↗
PubMed1982

Tricyclics with analgesic and antidepressant activity. 2. [[(Alkylamino)ethyl]thio]dibenzo[b,f]thiepins and 10,11-dihydro derivatives.

A series of [[(alkylamino)ethyl]thio]dibenz[b,f]thiepins (III) and their 10,11-dihydro derivatives (IV) was synthesized and subjected to broad analgesic/CNS screening. Preliminary results indicated a combination of analgesic/antidepressant profiles, similar to that observed for the [[(alkylamino)ethyl]thio]dibenz[b,f]oxepins (I) and their corresponding dihydro derivatives (II). The most active congener from the present series, 10b, shows an antinociceptive potency in the pentazocine range as assessed by phenyl-p-quinone-induced writhing (PQW) and tail flick in mice. It is also more than twice as active as imipramine in preventing tetrabenazine-induced ptosis (TBZ), a test widely recognized to be of predictive value for clinically efficacious antidepressants.

5-Hydroxytryptophan↗
PubMed1981

Novel tetracyclic spiropiperidines. 1. 3-Aryl-1,3-dihydrospiro[benzo[c]thiophene-1,4'-piperidines] as potential antidepressants.

A series of 3-aryl-1,3-dihydrospiro[benzo[c]thiophene-1,4'-piperidine] derivatives was synthesized and evaluated pharmacologically for potential psychotropic activity. Potent antidepressant-like activity was noted throughout the series, as assessed by tetrabenazine (TBZ) ptosis prevention in mice and potentiation of 5-hydroxytryptophan (5-HTP) induced behavioral effects in rats. A possible therapeutic advantage of the title compounds appears to be the overall low anticholinergic potential in comparison with the classic tricyclic antidepressants. Several congeners with nuclear halogen substitution also exhibited CNS stimulant properties, as evidenced by their ability to induce a dopamine agonist-like stereotypy and to increase the spontaneous motor activity in mice.

5-Hydroxytryptophan↗
PubMed1980

Tricyclics with analgesic and antidepressant activity. 1. [[(Alkylamino)ethyl]thio]dibenz[b,f]oxepins and 10,11-dihydro derivatives.

A series of [[(alkylamino)ethyl]thio]dibenz[b,f]oxepins (I) and their 10,11-dihydro derivatives (II) was synthesized and subjected to broad analgesic/CNS screening. Several analogues of both types, carrying small N-substituents and frequently a nuclear fluorine function, have been found to possess potent analgesic activity in the phenylquinone writhing assay (PQW) and the tail-flick test in mice. Many of these compounds also exhibited significant activity in antagonizing tetrabenazine-induced ptosis, as exemplified by 10b, 16b, and 18b. Results from the mouse jumping test indicated low physical dependence potential for these compounds, and further evidence for a nonnarcotic profile was provided by the absence of significant naloxone interactions with the tail-flick response. Compound 10b did not produce tolerance in mice following chronic administration in the PQW screen.

Amphetamine↗
PubMed1980

Synthesis and analgesic activity of some 5-(4-hydroxyphenyl)-2-azabicyclo[3.2.1]octanes.

A representative series of 5-(4-hydroxyphenyl)-2-azabicyclo[3.2.1]octanes was synthesized and evaluated in vitro, as well as in vivo, as potential analgetic agents. In general, moderate to good activity (19 twice as active as morphine) was observed in the phenylquinone writhing assay (PQW), while only marginal activity was detected by the tail-flick method. Compounds 19 and 18, being the most active in the PQW model, also demonstrated weak binding affinity for the opiate receptors labeled by [3H]naloxone in rat brain homogenates.

Analgesics↗
PubMed1979

Synthesis and analgesic activity of some spiro[dibenz[b,f]oxepin-10,4'-piperidine] derivatives.

A series of 10,11-dihydro-11-oxospiro[dibenz[b,f]oxepin-10,4'-piperdine] derivatives (II) was synthesized and evaluated for analgesic activity in the phenylquinone writhing assay (PQW) and the tail-flick test in mice. Preliminary structure-activity correlations indicate that optimum activity is associated with a short-chain (R less than or equal to C2) N substituent and a nuclear fluorine function, as exemplified by 9b. This compound, when administered orally, was equipotent to morphine in protecting against mouse writhing. The observation that the PQW activity of 9b remained relatively unchanged after naloxone challenge seems to favor a nonnarcotic profile.

Analgesics↗
PubMed1978

Synthesis and analgetic activity of some 5-aryl-2azabicyclo[3.2.1]octanes.

A series of 5-aryl-2-azabicyclo[3.2.1]octanes II has been synthesized and evaluated for analgetic agonist-antagonist activity. These compounds can be regarded as five-membered, conformationally more rigid analogues of the potent agonist-antagonist (-)-5-(3-hydroxyphenyl)-2-methylmorphan (I). Several of these compounds have demonstrated marked analgesic potency comparable to morphine in the mouse writhing assay. Structure-activity correlations, generated by varying N-substitution and O-acetylation of the phenolic function, seem to indicate that optimum activity is associated with an arylethyl side chain attached to the basic nitrogen. Among the most interesting compounds in this series are the phenethyl analogue 31 and its O-acetate 39; the former shows the profile of a well-balanced analgetic-antagonist virtually devoid of physical dependence liability as demonstrated in the rat infusion test.

Analgesics↗
PubMed1976

Synthesis of spiro[isobenzofuran-1(3H),4'-piperidines] as potential central nervous system agents.

Synthesis of 1'-methyl-3-phenylspiro[isobenzofuran-1(3H),4'-piperidine] (7a, HP 365) and the demethyl analogue 9a (HP 505) was prompted by recognition of an aminoalkyl(aryl)isobenzofuran moiety common to the antidepressants talopram (Lu 3-010) and trans-10,11-dihydro-5,10-epoxy-5-[3-(methylamino)propyl]-5H-dibenzo[a,d]cyclohepten-11-ol (MK-940). Convenient laboratory synthesis of 7a was provided by lithiation of 2-bromobenzhydryl methyl ether, followed by addition of 1-methyl-4-piperidone and acid-catalyzed cyclization. N-Dealkylation by standard methods afforded 9a. Synthesis of analogues was stimulated by discovery of marked inhibition of tetrabenazine-induced ptosis for lead compounds 7a and 9a. Optimal antitetrabenazine activity is associated with the 3-phenylspiro-[isobenzofuran-1(3H),4'-piperidine] moiety where nitrogen is basic. Modification of this moiety by introduction of large nitrogen substituents or a C-3 substituent greater than H significantly reduced antitetrabenazine activity. A series of analogues with aromatic substituents was investigated; however, few of these compounds were significantly more active than 7a and 9a. Compound 9a was selected for additional studies.

Animals↗
PubMed1975

Analgetic activity and in vitro binding constants of some N-alkyl-3-benzazocines.

A homologous series of 3-alkyl-1,2,3,4,5,6-hexahydro-8-hydroxy-6-methyl-3-benzazocines (2) has been synthesized. Analgetic activity and binding constants for the opiate receptor for 2 and for an analogous series of benzomorphans (1 and 3) are reported. In 1, hot-plate analgesic activity is lost on increase of the N-alkyl chain length from ethyl through butyl (lc-e) and regained with amyl (lf) and hexyl (lg). Compounds lc-e show that antagonist properties and binding constants are similar throughout the series. With 2, where there has been loss of steric constraints through removal of the 2,6-methano bridge of 1 and 3, greatly diminished analgetic activity and receptor affinity and no antagonist properties were observed. Like 1, however, greatest agonist activity was shown by the N-methyl (2c), amyl (2g), hexyl (2h), and heptyl (2i) homologs and there is a parallel of in vitro binding strength and analgetic activity.

Analgesics↗