Search

An extensive series of carboxyarylindoles has been evaluated for antiinflammatory activity in the carrageenin paw edema assay. The requirements for optimal antiinflammatory activity in this series are relatively specific: a central pyrrole nucleus with (a) a 3-carboxy-4-hydroxyphenyl moiety substituted directly on the nitrogen, (b) a 2-phenyl group (R2) with a substituent of low electronegativity, (c) absence of a substituent in the 3 position (R3), and (d) a system fused across the 4,5 positions (X), which is lipophilic, quasiplanar, and does not interact sterically with the N-phenyl group. One derivative, 3-(3-carboxy-4-hydroxyphenyl)-2-phenyl-4,5-dihydro-3H-benz[e]indole (42), has been selected for further study.

A series of [(3-aryl-1,2-benzisoxazol-6-yl)oxy]acetic acids was synthesized and tested for diuretic activity in saline-loaded mice and in conscious, water-loaded dogs. The structural requirements for good diuretic activity in both mice and dogs were found to be very specific. In summary, the compounds with the best diuretic activity (13i, 13q, and 13ff) were substituted with a 2-fluorophenyl group at the 3 position and chlorine or bromine at the 7 position. Compound 13ff, [(7-bromo-3-(2-fluorophenyl)-1,2-benzisoxazol-6-yl]oxy]acetic acid (HP 522), was found to be moderately uricosuric in chimpanzees and was selected for further development.

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.

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.

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.

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.

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.

The synthesis and antihypertensive activity of several piperidinebenzenesulfenamides related to the previously reported potent hypotensive agents 1 and a series of 1-arypiperazine-4-benzenesulfenamides 7 are described. A number of the latter compounds exhibit marked antihypertensive properties. The most interesting of these compounds, 7a and 7k, have been evaluated in several other animal models. In addition, benzenesulfinamides 9a and 9b and benzensulfonamides 10a and 10b have been prepared for comparison purposes.

Antidepressant-like activity, as evidenced by marked inhibition of tetrabenazine-induced ptosis, was previously reported for (+/-)-4,5-dihydro-4-phenyl-3H-1,3-benzodiazepine derivatives. Since optimal antitetrabenazine activity was associated with (+/-)-4,5-dihydro-2,3-dimethyl-4-phenyl-3H-1,3-benzodiazepine (9k, HRP 543) and the 2-ethyl-3-methyl analogue (10k), the synthesis and evaluation of nuclear-substituted derivatives of these two compounds was also investigated. The initial synthesis involved Friedel-Crafts acylation of substituted benzenes with 2-nitrophenylacetyl chloride to afford 1-aryl-2-(2-nitrophenyl)ethanones 2, which were converted in five steps to (+/-)-alpha-aryl-N-methyl-2-nitrobenzeneethanamines 7. Greater flexibility with respect to the introduction of nuclear substituents was achieved by conversion of 2-nitrotoluene derivatives to 2 via acylation of intermediate beta-(dimethylamino)-2-nitrostyrenes with various aroyl chlorides and hydrolysis. Reductive amination of 2 with methylamine and sodium cyanoborohydride afforded 7 directly and significantly reduced the number of synthetic steps. Reduction of 7a-j to diamines 8a-j and cyclization with appropriate ortho esters gave nuclear-substituted analogues of 9k and 10k. Marked antitetrabenazine activity was associated with many of these compounds. Significant enhancement of activity with respect to the unsubstituted analogues 9k and 10k was not observed, with the exception of 9c which appeared to be slightly more potent than 9k.

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.

4-(Dimethylamino)- and 4-(methylamino)-3'-arylspiro[cyclohexane-1,1'(3'H)-isobenzofuran] derivatives were prepared as analogues of previously reported 3-arylspiro[isobenzofuran-1(3H),4'-piperidines]. Metalation of benzanilide with n-butyllithium, addition of 4-(dimethylamino)cyclohexanone, and acidification afforded a mixture of cis- and trans-4-(dimethylamino)spiro[cyclohexane-1,1'(3'H)-isobenzofuran]-3'-ones (1a,b), which were separated by fractional crystallization. Addition of aryllithium or aryl Grignard reagents to 1a,b and formic acid reduction afforded cis- and trans-4-(dimethylamino)-3'-arylspiro[cyclohexane-1,1'(3'H)-isobenzofurans] 3a-f, which were converted to secondary amine analogues 5a-e. Tentative stereochemical assignments are based on chemical arguments and are supported by 13C NMR chemical shift data. Marked inhibition of tetrabenazine-induced ptosis is a property of most antidepressants, and significant antitetrabenazine activity is observed for several of these compounds. Optimal antitetrabenazine activity is associated with the cis-3'-phenyl series, and the cis secondary amine 5a is approximately twice as potent as the cis tertiary amine 3a. The various compounds are relatively weak with respect to potentiation of L-5-hydroxytryptophan-induced seizures.

The synthesis of 1'-[3-(4-fluorobenzyoyl)propyl]-3-phenylspiro[isobenzofuran-1(3H),4'-piperidine] (2a) and eight halo and methoxy analogues is described. The compounds were generally more potent per os than chlorpromazine in the Sidman avoidance paradigm in rats and less potent than haloperido. 1'-[3-(4-Fluorobenzoyl)propyl]-3-(4-fluorophenyl)spiro[isobenzofuran-1(3H),4'-piperidine] (2e) approached the per os potency of haloperidol in this test and was shown to be active in inhibiting monkey avoidance also. Compound 2e was much less active than haloperidol in antagonizing apomorphine-induced emesis in dogs, apomorphine-induced stereotypy in rats, and amphetamine-induced circling in lesioned rats. This lack of nonselective, dopamine-receptor blocking effects makes 2e attrative as a potential neuroleptic.

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.

An extensive series of 3-(1-indolinyl)benzylamines and related compounds was synthesized and tested for analgesic activity. After a detailed study of structure-activity relationships, 3-(1-indolinyl)benzylamine (2b) was selected for further investigation as the most interesting member of this novel class of compounds. It was active in both the phenylquinone writhing and tail-flick assays for analgesic activity. No motor deficits were observed in the rotorod test, and 2b was found to be free of any other effects on the central nervous system. The compound did not bind to opiate receptors, since it was inactive in inhibiting the stereospecific binding of [3H]naloxone in rat brain homogenates. Thus, 3-(1-indolinyl)benzylamine represents a novel analgesic with an unusual chemical structure and biological profile.

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.

The indazole, benzisothiazole, and benzisothiazole 1,1-dioxide analogues of [[7-chloro-3-(2-fluorophenyl)-1,2-benzisoxazol-6-yl]oxy]acetic acid were synthesized and tested for diuretic activity in saline-loaded mice. Each analogue was found to be less active than the parent benzisoxazole: the diuretic activity followed the order O greater than S greater than N = SO2 in regard to the heteroatom in the 1-position of the ring.

The synthesis and antihypertensive activity of a series of 2-benzamido-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]-quinolizines are reported. A number of these compounds exhibit extremely potent hypotensive properties (e.g., N-methylbenzamides 42, 48, and 50 and N-ethylbenzamide 53 cause drops of 110, 103, 79, and 83 mmHg, respectively, in systolic blood pressure in the spontaneous hypertensive rat at the screening dose of 50 mg/kg po). Structure-activity relationships for the entire series are discussed.