Synthesis, Computational and Pharmacological Evaluation of N-(2-benzoyl- 4-chlorophenyl)-2-(4-(Substituted Phenyl) Piperazin-1-yl) Acetamides as CNS Agents

BACKGROUND

A series of new N-(2-benzoyl-4-chlorophenyl)-2-(4-(substituted phenyl) piperazin-1-yl) acetamides (3a-j) have been synthesized by the chloroacetylation of 2-amino-5- chlorbenzophenone which was further reacted with substituted phenylpiperazine.

MATERIAL

The chemical structures of the compounds were confirmed on the basis of their TLC, IR, 1HNMR, 13CNMR and by elemental analysis. The physicochemical similarity of the target compounds with respect to standard drug diazepam was assessed by calculating from a set of physicochemical properties using software programs.

CONCLUSION

Molecular docking studies revealed that the target compounds correctly dock into the binding pocket of the GABAA receptor, while their bioavailability/drug-likeness was predicted to be acceptable but requires future optimization. The anxiolytic and skeletal muscle relaxant activity of the target compounds (3a-j) were evaluated in albino mice. Among them, compound 3h showed potent anxiolytic and skeletal muscle relaxant activity.

Synthesis and pharmacological screening for muscle relaxant, anticonvulsant, and sedative activities of certain Organic compounds produced by Michael addition

Michael addition of certain nucleophiles on alpha, beta-unsaturated ketones 1 led to the formation of adducts 2-7 as well as the reaction of arylidene derivatives with secondary amines afforded the amino compounds 9 and 11. Also, dialkylmalonates were treated with alpha-cyano cinnamide to afford 13. On the other hand, double Michael cycloaddition of ethylcyanoacetate or tetrachlorophthalic anhydride to the suitable divinylketone were synthesized to produce 15-17. Selected compounds (13 and 6) were screened for muscle relaxant, anticonvulsant, and sedative activities using established pharmacological models. Their activities were compared with that of phenobarbital sodium taken as standard. Compound 6 was the most potent muscle relaxant while compounds 13a and 13c offered the highest anticonvulsant activity. Meanwhile compound 13c showed the highest potentiation of phenobarbital induced sleep in mice.

Behavioural effects of thieno and pyrazolo [2,1] benzothiazepine derivatives in mice

Behavioural studies were conducted in mice with a number of hetero[2,1]benzothiazepine derivatives, analogues of tianeptine. Previously published studies in mice have shown that some of these compounds were effective in the tetrabenazine and Porsolt tests. In the present study, four of the 15 compounds under study potentiated the actions of 5-hydroxytryptophan (5-HTP, 50 mg/kg i.p.), but no significant antagonism of the apomorphine (16 mg/kg s.c.)-induced hypothermia and potentiation of the amphetamine actions was found. Moreover, some of them inhibited the stereotyped behaviour and/or climbing behaviour of low doses of apomorphine and compound 2 was effective in the plus-maze test. These compounds also produced a slight inhibition of exploratory behaviour in the holeboard test. On the other hand, no significant muscle relaxant and anticonvulsant activities were observed at any dose employed. Together, these data suggest that some of the compounds under study combine the antidepressant effects with additional neuroleptic or anxiolytic activities in mice.

Dantrolene analogues revisited: general synthesis and specific functions capable of discriminating two kinds of Ca2+ release from sarcoplasmic reticulum of mouse skeletal muscle

The general synthesis of dantrolene analogues with various substituents on its phenyl ring has been developed via palladium-catalyzed cross-coupling reactions, the Stille or Suzuki reaction, as the key step. The effects of synthesized analogues have been evaluated by two kinds of Ca(2+) release modes from sarcoplasmic reticulum (SR) of mouse skeletal muscle fibers based on: (1) the measurement of twitch contraction caused by the physiological Ca(2+) release (PCR) of intact skeletal muscle and (2) the rate of Ca(2+)-induced Ca(2+) release (CICR) in saponin-treated skinned muscle fibers. Although dantrolene, a lead compound, inhibits both twitch contraction and CICR, some structurally modified analogues exhibit one or the other of these effects. The methoxy congener, GIF-0185, potently inhibits the twitch contraction without affecting the CICR, while GIF-0166 and GIF-0248, the ortho-nitro regioisomer and ortho, ortho-dinitro substituted analogues, respectively, doubly potentiate the CICR exclusively.

[New findings on the synthesis of the centrally acting muscle relaxant chlormezanone and its resolution of a gram scale using a Chiralcel OD column]

2-(4-Chlorophenyl)-4-metathiazanone (2) is the intermediate product for the two step-synthesis of chlormezanone (1), a centrally acting muscle relaxant. The second step includes the oxidation of its sulfur atom. It has been found that the foregoing reaction of 4-chlorobenzaldehyde with methylamine forming the hemiaminale and the subsequent addition of beta-mercaptopropionic acid leads to a remarkable better yield (67% of th.) than the route via the hemimercaptale (42% of th.). 2 could be oxidized with sodium perborate superior to potassium permanganate. The racemic chlormezanone (1) is resolved quickly on a gram scale by preparative column chromatography on a Chiralcel OD column (tris(3,5-dimethyl-phenyl-carbamoyl)cellulose on silicagel). The resolution needed only 40 min, if flow rate, composition of the mobile phase and temperature as the most important factors are determined prior with an analytical column. Both dissociation constants could be determined for the first time with the aid of a log pKa-Titrator of the Sirius Co., which needs for the registration of the curves only 15-17 min in the pH range of 2-12. This speed outplayed the disturbing cleavage of the S-C bond of chlormezanone at strong acidic and alkaline pH values.

Indanylidenes. 2. Design and synthesis of (E)-2-(4-chloro-6-fluoro-1-indanylidene)-N-methylacetamide, a potent antiinflammatory and analgesic agent without centrally acting muscle relaxant activity

Extension of the structure-activity relationship studies that led to the discovery of the nonsedating potent muscle relaxant, antiinflammatory, and analgesic agent (E)-2-(4,6-difluoro-1-indanylidene)acetamide, 1, has given rise to (E)-2-(4-chloro-6-fluoro-1-indanylidene)-N-methylacetamide, 2. Compound 2 is a potent antiinflammatory and analgesic agent without centrally acting muscle relaxant activity.

Indanylidenes. 1. Design and synthesis of (E)-2-(4,6-difluoro-1-indanylidene)acetamide, a potent, centrally acting muscle relaxant with antiinflammatory and analgesic activity

The design of rigid cyclic analogues derived from cinnamamide 1, (E)-N-cyclopropyl-3-(3-fluorophenyl)prop-2-enamide, and beta-methylcinnamamide 2, (E)-N-cyclopropyl-3-(3-fluorophenyl)but-2-enamide, has led to the discovery of the potent, centrally acting muscle relaxant (E)-2-(4,6-difluoro-1-indanylidene)acetamide, 17. Compound 17 also possesses potent antiinflammatory and analgesic activity. This paper describes the synthesis and the muscle relaxant, antiinflammatory, and analgesic structure-activity relationships of 17 and 67 of its analogues. Compound 17 has been taken into phase I clinical trials.

Synthesis and benzodiazepine receptor affinity of pyrazolo[1,5-a]pyrimidine derivatives. 3. New 6-(3-thienyl) series as alpha 1 selective ligands

New 3-aryl-6-(3-thienyl)pyrazolo[1,5-a]pyrimidin-7-ones (2a-j) are synthesized and evaluated in vitro on Bz/GABA(A) receptors and on recombinant benzodiazepine receptors (alpha x beta 2/3 gamma 2; x = 1-3, 5) expressed in HEK293 cells. SAR studies on the new compounds are conducted and molecular modeling is accomplished to better investigate requirements leading to subtype selectivity. Some of the synthesized compounds are tested in vivo to explore their pharmacological effect as a consequence of their high alpha 1 beta 2 gamma 2 subtype selectivity observed in vitro.

[Synthesis and pharmacological study of three 1-alkyl-3-(ethoxycarbonylmethylene)-2-oxo quinoxalines]

The acute toxicity study and the psychotropic activity of three alkylated derivatives of 3-(ethoxycarbonylmethylene) -2-oxo quinoxaline did not demonstrate any toxicity of these products at therapeutic dosages. In the animal, these compounds have sedative, myorelaxant and anxiolytic properities.

Study of the antidepressant activity of 4-phenyl-2-thioxo-benzo[4,5]thieno[2,3-d]pyrimidine derivatives

A series of 23 4-phenyl-2-thioxo-benzo[4,5]thieno[2,3-d]pyrimidine derivatives were tested for acute toxicity and antidepressant activity in mice. Eight of the 23 compounds tested clearly antagonised the tetrabenazine effects and four of them (5, 7, 19, 23) showed activity values ranging from 40 to 75%, close to those shown by imipramine and viloxazine, the drugs chosen as reference standards. Compounds 7, 19 and 23 were also notably effective in the Porsolt test, shortening the immobility period of mice by more than 20%. The values obtained were very close to those elicited by imipramine and viloxazine. The most effective compounds in these tests were found among those bearing a primary amine or a benzoylamino group at the position 3 of the thieno[2,3-d]pyrimidine general structure (7, 19 and 23). The substitution of the thioxocarbonyl group at position 2 by a methylmercapto substituent maintained the activity (23). Compounds 7, 19 and 23 were chosen as prototypes for the design of new molecules with better antidepressant activity. These compounds did not present the adverse anticholinergic effects found in most tricyclic antidepressant drugs.

Synthesis of optically active NC-1800, a therapeutic agent for urinary disturbance

A new synthetic method for chiral oxazolidinone derivatives, therapeutic agents for treating urinary disturbance, is described. The condensed compound obtained from chiral 1-amino-3-phenyl-2-propanol and 1-phenyl-3-morpholino-1-propanone was reduced with Me4NBH(OAc)3 to give the intermediate, 1-(3-morpholino-1-phenylpropyl)amino-3-phenyl-2-propanol (MAPP) in 34% diastereomeric excess (d.e.). MAPP was converted to an urethane and purified by recrystallization of its methanesulfonate, to afford a single isomer, (2R)-1-[N-[(1S)-3-morpholino-1-phenylpropyl]-N -ethoxycarbonyl]amino-3-phenyl-2-propanol methanesulfonate (4-A. methanesulfonate).

Benzodiazepine receptor ligands. 4. Synthesis and pharmacological evaluation of 3-heteroaryl-8-chloropyrazolo[5,1-c][1,2,4] benzotriazine 5-oxides

The synthesis of new 3-heteroaryl-8-chloropyrazolo[5,1-c][1,2, 4]benzotriazine 5-oxides and their binding activities at the central benzodiazepine receptor (BZR) are reported. The derivatives substituted at the 3-position with electron-rich five-membered rings, such as pyrrole 11, 2-thiophene 13c, or 3-thiophene 13d, showed good affinity values for BZR. In in vivo tests the 3-(thien-3-yl)-8-chloropyrazolo[5,1-c][1,2,4] benzotriazine 5-oxide (13d) showed selective anticonvulsant activity.

[3H]Azidodantrolene: synthesis and use in identification of a putative skeletal muscle dantrolene binding site in sarcoplasmic reticulum

Dantrolene sodium is a medically important hydantoin derivative that interferes with release of Ca2+ from intracellular stores of skeletal muscle by an unknown mechanism. Identification of the molecular target of dantrolene would greatly aid in understanding both the mechanism of action of the drug and the dynamics of intracellular Ca2+ release in muscle. [3H]Azidodantrolene was designed and synthesized as a photoaffinity analogue in order to identify a putative dantrolene receptor in skeletal muscle. Introduction of 1 mole-atom of tritium into aldehyde 5b was required during radioligand synthesis in order to ensure high enough specific activity for detection of photo-cross-linked proteins by fluorographic methods. This was accomplished by reduction of ester 3 with custom synthesized, 100% tritium-labeled lithium triethylborotritide, followed by oxidation to 5b by manganese(IV) oxide. Compound 6b was demonstrated to be >/=95% tritium-labeled at the imine position by NMR spectroscopy, and the specific radioactivity of [3H]azidodantrolene sodium was empirically determined by HPLC and liquid scintillation counting to be 24.4 Ci/mmol, approximately 85% of theoretical maximum. [3H]Azidodantrolene was found to be pharmacologically active in ligand-receptor binding studies with skeletal muscle sarcoplasmic reticulum membranes. Photo-cross-linking experiments analyzed by SDS-PAGE and tritium fluorography have identified a approximately 160-kDa specifically labeled protein as the putative, intracellular, skeletal muscle dantrolene receptor. This photolabeled protein comigrates with a protein in Western blots immunologically cross-reactive to a polyclonal anti-rabbit skeletal muscle ryanodine receptor antibody. Thus, the putative dantrolene receptor may be related to the skeletal muscle ryanodine receptor.

[Synthesis and pharmacologic study of 1,5-benzodiazepine-2,4-diones and their alkyl derivatives]

From the pharmacodynamic studies of 1,5-benzodiazepin-2,4-diones and alkyl derivatives prepared in our laboratories, we can conclude that these products are not toxic at therapeutic dosage. They have sedative, myorelaxant and anxiolytic actions. The two products alkylated by allyl bromide have also hypnotic, sedative and anticonvulsant properties.

[Synthesis and pharmacologic study of 1,5-benzodiazepine-2,4-dithiones and their alkyl derivatives]

From the pharmacodynamic studies of 1,5-benzodiazepine-2,4-dithiones and alkyl derivatives, we can conclude that these products are not toxic at therapeutic dosage. They have sedative, myorelaxant and anxiolytic actions.

CNS effects of a series of 1,2,4-triazolyl heterocarboxylic derivatives

A series of 1,2,4-triazolyl heterocarboxylic derivatives were tested for acute toxicity and CNS effects in mice. Several of these compounds demonstrated clear psychostimulant effects. Other components of the series, however, showed a definite central depressant activity. Some of the screened derivatives showed interesting anxiolytic properties.

Synthesis of some indane derivatives of central muscle relaxant and anticonvulsant profiles

A series of 2,2-bis(hydroxymethyl)indane derivatives 1a-f, 2a-e and 3a-f were synthesized to investigate their central muscle relaxant and anticonvulsant activities. The synthesized compounds 1a-f, 2a-e and 3a-f were found to be devoid of central muscle relaxant activity using meprobamate (100 mg/kg) as a reference standard. However, they showed remarkable anticonvulsant properties in a dose of 80 mg/kg (s.c.) compared with diphenylhydantoin sodium (80 mg/kg) as a reference standard.

Agents for the treatment of overactive detrusor. IX. Synthesis and pharmacological properties of metabolites of N-tert-Butyl-4,4-diphenyl-2-cyclopentenylamine (FK584) in human urine

We synthesized the racemates of the five presumed metabolites (1b-f) of (S)-(--)-N-tert-butyl-4,4-diphenyl-2-cyclopentenylamine hydrochloride (FK584, S(--)-1a), a novel agent for the treatment of overactive detrusor syndrome, in order to confirm the structures of the metabolites and also to evaluate their inhibitory activity against detrusor contraction. (+/-)-N-tert-Butyl-4-(4-hydroxyphenyl)- and 4-(4-hydroxyphenyl)- and 4-phenyl-2-cyclopentenylamines (1b--e) were synthesized via 5-(4-methoxyphenyl)- and 5-(4-benzyloxy-3-methoxyphenyl)-5-phenyl-2-cyclopenten-1-one (9g, h), respectively. Compounds 1b-f prepared in this study were identical with the metabolites in human urine in gas chromatography-mass spectrometry and analytical HPLC. The inhibitory activity of compounds 1b-f against detrusor contraction in vitro induced by electrical field stimulation in guinea-pigs was less potent than that of FK584.

Synthesis and anti-inflammatory evaluation of new sulfamoylheterocarboxylic derivatives

A series of new sulfamoylthiophene and sulfamoylpyrazole carboxylic acid derivatives was synthesized. Some of these compounds show interesting analgesic properties and significant nonsteroidal anti-inflammatory activities in several models of inflammation.

Syntheses and pharmacological properties of new 2-aminobenzimidazole derivatives

The paper reports the structures, syntheses and pharmacological properties of new compounds having a 2-aminobenzimidazole group. They exhibit various activities: histamine H1- and H2-receptors blocking activities, antilipidemic and platelet antiaggregatory, anti-inflammatory and analgesic properties, antimicrobial, fungicidal, parasiticide, antiarrythmic activity and muscle relaxant, comparable to those of drugs used in therapy.

Synthesis and pharmacological study of 5,6,8,9-tetrahydro-4H, 7H-pyrrolo[1,2-a]cyclopenta[b]thieno[3,2-f][1,4]diazepines

The paper reports the synthesis of a series of 5,6,8,9-tetrahydro-4H, 7H-pyrrolo[1,2-a]cyclopenta[b]thieno-[3,2-f][1,4]diazepines and the results of the study on their CNS activity in mice. The pharmacological properties of a previously prepared series of 5,6,7,8,9,10-hexahydro-benzo-analogs is also described.

Synthesis and muscle relaxant activity of cyclic baclofen analogues

Some new cyclic analogues of baclofen have been prepared and characterized, starting from 4-(4-chlorophenyl)-pyrrolidone. When tested in comparison with the parent compound, they exhibited only a moderate muscle relaxant activity.

Synthesis and CNS activities of pyridopyrazinone and pyridodiazepinone derivatives

New tricyclic derivatives with cyclocondensed pyrido-pyrazine 7,10 and pyrido-diazepine 20a,20b skeletons were synthetized and biologically investigated. The compounds, preliminarily tested on explorative, muscle relaxing, antinociceptive, spontaneous motor activities and influence on the narcotic effect of Evipan, revealed interesting CNS depressant and analgesic activities. The pyrido[2,3-e]pyrrolo[1,2-a]pyrazine structure of 7 appeared the most promising for analgesic and neuroleptic activities. The above compounds were assayed also for their capacity to inhibit DNA synthesis in Ehrlich ascites tumor cells; 20a appeared to be able of inducing a significant inhibition.

Researches on psychotropic agents. IV. Synthesis and neuropsychopharmacological effects of 1,3,4,14 b-tetrahydro-10-methyl-2H,10H- pyrazino[2,1-d] pyrrolo[1,2-b][1,2,5]benzotriazepine and its derivatives

The synthesis and neuropsychopharmacological properties of new 1,3,4,14b-tetrahydro-2H,10H-pyrazino [2,1-d] pyrrolo [1,2-b] [1,2,5] benzotriazepine derivatives related to antidepressant agent aptazepine are reported. The new derivatives displayed sedative-miorelaxant activity in mice, but no significant antagonist effect on clonidine blockade of phenylquinone-induced abdominal constriction. Among test compounds 4a, 4l and 4n showed high antinociceptive effect on the hot-plate test and compound 4e protected from death and convulsion all the electroshocked animals.

Neuroleptic activity of 10-(4-methyl-1-piperazinyl)-thieno[3,2-b] [1,5]benzoxazepine and benzothiazepine derivatives

Two series of compounds, structurally related to clozapine (CAS 5786-21-0), were tested for their neuroleptic activity. The derivatives 7-chloro-10-(4-methyl-1-piperazinyl)-thieno[3,2-b][1,5]benzoxazepine and 7-chloro-10-(4-methyl-1-piperazinyl)-thieno[3,2-b][1,5]benzothiazepine at high doses were not cataleptogenic and only very weakly antagonized the amphetamine-or apomorphine-induced stereotyped behaviour in the rat, whereas at low doses they antagonized the amphetamine-induced hypermotility in mice. Thus these compounds might be efficient neuroleptics with little propensity to cause extrapyramidal side effects. On the other hand, the unsubstituted compound 10-(4-methyl-1-piperazinyl)-thieno[3,2-b][1,5]benzothiazepine appeared to be an efficient neuroleptic agent with a greater propensity to cause these side effects.

Pyrrylphenylethanones related to cathinone and lefetamine: synthesis and pharmacological activities

The synthesis of various pyrrylphenylethanones resembling cathinone and lefetamine is described starting from 2-chloro-1-(1-methyl-1H-pyrrol-2-yl)-2-phenylethan-1-one. Some derivatives showed good antinociceptic activity, comparable to that of morphine. The neuropsychopharmacological profile of title compounds has been also studied to explore their action on C.N.S.

[Synthesis of some 4-nitrophenylfuran derivates analogs of Dantrolene]

Six new phenacylidene derivatives of 5-(4-nitrophenyl)furan were obtained by reacting 5-(nitrophenyl)furfural with 4 substituted acetophenones.

Non-steroidal antiinflammatory agents. VII. Synthesis and antiinflammatory activity of 5-methyl-10,11-dihydro-5H-pyrrolo [1,2-b] [1,2,5]benzotriazepine-11-acetic acid and its 10-aroyl derivatives

The synthesis of 5-methyl-10,11-dihydro-5H-pyrrolo [1,2-b] [1,2,5]benzotriazepine-11-acetic acid and its 10-aroyl derivatives is reported. Compounds were evaluated for antiinflammatory activity by the carrageenin-induced rat paw edema method. Antinociceptic activity was tested by the hot plate and Randall-Selitto tests. General neuropsychopharmacological effects were also screened. All test compounds showed antiinflammatory effect comparable to that of tolmetin.

Synthesis and biological testing of certain 2-(5-substituted-2-thienylthio)benzoic acid derivatives

The syntesis of a number of 2-(5-substituted-2-thienylthio)benzoic acid derivatives is described. The synthesized compounds were screened for their muscle relaxant and parasympatholytic activities and the results are reported.

[Synthesis and pharmacologic activity of 9-R-octahydroindolo[2,3-a]quinolazine]

By acid induced cyclization of quinolizidin-1-one 4-R-phenylhydrazones several derivatives of 1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine (1), bearing a substituent on position 9, were prepared. When R = Cl this reaction gave rise also to a red-orange compound to which the structure (V) of 1-(p-chloro)phenylazo-3,4,6,7,8,9-hexahydroquinolizine was assigned. Substances (1 b)-(1-f) were tested for spontaneous locomotor, muscle relaxant, analgesic, antiinflammatory, diuretic and cardiovascular activities and for influence on pentylentetrazole and sodium pentobarbital actions. Interesting levels of activity were exhibited in several cases.

Benzodiazepine receptor ligands. Synthesis and preliminary pharmacological evaluation of some 3-aryl-6-thioalkyl-, 3-aryl-6-alkylsulphinyl-, 3-aryl-6-alkylsulphonyl-, and 3-aryl-6-alkoxy-1,2,4-triazolo[3,4-a]phthalazines

A series of 3-aryl-6-alkoxy- and some 3-aryl-6-thioalkyl-, 3-aryl-6-alkylsulphinyl-, and 3-aryl-6-alkylsulphonyl-1,2,4-triazolo[3,4-a]phthalazines were synthesised and tested for inhibition of the in vitro binding of 3H-Diazepam to benzodiazepine receptors in membranes isolated from rat brain synaptosomes. 6-Alkoxy-3-(4'-methoxy)phenyl-1,2,4-triazolo[3,4-a]phthalazines were more active than or as active as diazepam in the binding assay (Ki nM) but unlike diazepam their binding to the benzodiazepine receptors was not enhanced by 4-aminobutyric acid. These compounds did not antagonize pentylenetetrazole induced convulsions and were inactive in modifying the conditioned behaviour of rats. Compound (II a) counteracted the muscle relaxant effects of diazepam (traction test). These results suggest that (II a) may be a benzodiazepine receptor antagonist.

1-[[[5-(substituted phenyl)-2-oxazolyl]methylene]amino]-2,4- imidazolidinediones, a new class of skeletal muscle relaxants

A series of 1-[[[5-(substituted phenyl)-2-oxazolyl]methylene]amino]- 2,4-imidazolidinediones (6a-t) was synthesized, and the compounds were evaluated for direct skeletal muscle inhibition in the pithed rat gastrocnemius muscle preparation. The correctness of structural assignment of the new series was verified by alternate, unequivocal synthesis of one representative structure (6f). The phenyloxazoles 6d, 6g, 6j, 6k, and 6l exhibited significant skeletal muscle relaxant activity when administered intravenously and orally. The skeletal muscle relaxant effect of these five compounds is similar to that of other direct-acting skeletal muscle relaxants. The oxazole moiety proved to be an acceptable isosteric replacement for furan, as the biological activity in the oxazole series was retained. The synthesis of this new class of compounds is described, and pharmacologic evaluation data are presented. A discussion of structure-activity relationships is also presented.

[Central muscle relaxant activities of 2-methyl-3-aminopropiophenone derivatives]

In this experiment, we synthetized new 2-methyl-3-aminopropiophenone (MP) derivatives, whose structure is known to have central muscle relaxant activities, and quinolizidine and indan . tetralin derivatives derived from MP by cyclization, and we investigated the central muscle relaxant activity. Among the quinolizidine derivatives, there was a very strong central depressant agent, trans (3H, 9aH)-3-(p-chloro) benzoyl-quinolizidine (HSR-740), and among the indan . tetralin derivatives, there was an excitant agents, trans (1H, 2H)-5-methoxy-3, 3-dimethyl-2-piperidinomethyl indan-1-ol (HSR-719). From the results, these derivatives were not considered to be adequate for central muscle relaxant. Among the MP derivatives, (4'-chloro-2'-methoxy-3-piperidino) propiophenone HCl (HSR-733) and (4'-ethyl-2-methyl-3-pyrrolidino) propiophenone HCl (HSR-770) strongly inhibited the cooperative movement in the rotating rod method using mice, and it exerted almost the same depressant activity on the cross extensor reflex using alpha-chloralose anesthetized rats. However, the inhibitory effects of HSR-733 on the anemic decerebrate rigidity and the rigidity induced by intracollicular decerebration in rats were weaker than those of HSR-770 and eperisone. In spinal cats, at a low dose (5 mg/kg, i.v.), HSR-733 depressed monosynaptic and dorsal root reflex potentials as compared with polysynaptic reflex potentials, and inhibitory effects of HSR-733 on these three reflex potentials were more potent than those of eperisone and HSR-770. Although HSR-770 acts on the spinal cord and supraspinal level on which eperisone has been reported to act, HSR-733 may mainly act on the spinal cord. These results indicate that the MP derivative with a 2-methyl group may be suitable as a central muscle relaxant. HSR-770, which has equipotent muscle relaxant activity to eperisone, exerted strong inhibitory effects on oxotremorine-induced tremor and weak inhibitory effects on spontaneous motor activity in the Animex method using mice, as compared with eperisone.

[Pharmacologic activity of tert-aminoalkyl derivates of quinoxalinone, aza- and diaza-quinoxalinone]

Eight tert-aminoalkyl derivatives of 3-methyl-6R-quinoxalin-2-one, 3-methyl-6/8-azaquinoxalin-2-ones and 3-methyl-6,8-diazaquinoxalin-2-one, previously selected for their deconditioning activity in rats were now tested in mice for analgesic, explorative and incoordinating (muscle relaxant) activities; acute toxicity was also determined. Several compounds show a good degree of activity in the tests used.

Synthesis and central nervous system properties of 2-[(alkoxycarbonyl)amino]-4(5)-phenyl-2-imidazolines

A series of 2-[( alkoxycarbonyl )amino]-4(5)-phenyl-2-imidazolines was prepared and evaluated for central nervous system (CNS) effects (antidepressant, anticonvulsant, muscle relaxant, and depressant) in animal models. Some separation of those CNS activities was achieved through substitutions on the phenyl and imidazoline moieties. Halo-substituted phenyl compounds were among the most potent antidepressants in this series, while imidazole N-alkylation produced compounds with increased depressant effects (loss of righting reflex, mouse behavior). Comparison of in vitro and in vivo data for pairs of 2-[(methoxycarbonyl)amino]-4(5)-phenyl-2-imidazolines and their parent, 2-amino-4(5)-phenyl-2-imidazolines, suggests that the title compounds were prodrugs for the 2-amino-4(5)-phenyl-2-imidazolines in inhibition of norepinephrine reuptake.

Synthesis and skeletal muscle relaxant activity of 3-(aminoacyl)-1-[[[5-(substituted phenyl)-2-furanyl]methylene]amino] -2,4-imidazolidinediones

A series of 3-(aminoacyl)-1-[[[5-(substituted phenyl)-2-furanyl] methylene]amino]-2,4-imidazolidinediones was synthesized and evaluated for skeletal muscle relaxant activity. All compounds were active by the intravenous route, and nine of 11 were active orally. One compound was very active when evaluated by the mouse Straub tail and rotarod tests; its efficacy index (ED50 rotarod/ED50 Straub tail) was 2.0, while its therapeutic index (LD50/ED50 Straub tail) was > 225.

Novel peptidoaminobenzophenones, terminal N-substituted peptidoaminobenzophenones, and N-(acylglycyl)aminobenzophenones as open-ring derivatives of benzodiazepines

Peptidoaminobenzophenones (1), terminal N-substituted peptidoaminobenzophenones (14), and acylglycylaminobenzophenones (16) were prepared as a novel series of ring-opened derivatives of 1,4-benzodiazepine. Z-Gly- and Z-Ala-N-methylaminobenzophenones (4) were treated with HBr-HOAc to give Gly- and Ala-N-methylaminobenzophenone hydrobromides (8). Reaction of 8 with chloroacetyl chloride in dimethylformamide (DMF) or hexamethylphosphoramide (HMPA) gave chloracetamide (13), which was allowed to react with various amines to afford a number of terminal N-substituted derivatives (14). Reaction of 8 with various acyl halides in HMPA or DMF gave a number of acylglycyl-N-methylaminobenzophenones (16). Peptidoaminobenzophenones (1) were also prepared by several convenient methods. Many of these compounds exhibited high CNS activity in animals when given orally. In antianxiety activity the potency of some compounds is equal to or higher than that of diazepam.

Peptidoaminobenzophenones, a novel class of ring-opened derivatives of 1,4-benzoidazepines

A series of noval peptidoaminobenzophenones has been prepared via several routes and was evaluated for CNS activity. The structure--activity relationships in the series are discussed. In general, dipeptido-N-methylaminobenzophenones showed higher activities than the corresponding NH derivatives. Some compounds had very high activities in antipentylenetetrazole and antifighting tests in mice when orally administered. Very weak toxicity was also found in these compounds. Water solubility of the peptidoaminobenzophenones and their salts were tested. Possible in these compounds. Water solubility of the peptidoaminobenzophenones and their salts were tested. Possible in vivo conversion of peptidoaminobenzophenone by enzymatic cleavage of the terminal amino acid, followed by chemical cyclization to 1,4-benzodiazepine, is also discussed. Such novel open-ring derivatives of 1,4-benzodiazepine may serve as useful CNS agents.

Synthesis and skeletal muscle relaxant activity of quaternary ammonium salts of dantrolene and clodanolene

A series of quaternary ammonium salts of dantrolene and clodanolene was prepared and evaluated for skeletal muscle relaxant activity. The quaternary ammonium salts exhibit greater aqueous solubility and, therefore, facilitate intravenous administration. One member of this series, although less effective orally, exhibited greater aqueous solubility than the sodium salt. When administered intravenously, it was a more potent antagonist of skeletal muscle contraction and yielded comparable therapeutic and muscle relaxant efficacy indexes.

Kojic amine--a novel gamma-aminobutyric acid analogue

A series of compounds containing the 3-hydroxy-4H-pyran-4-one nucleus has been synthesized and tested as potential skeletal muscle relaxants. Reduction of 2-(azidomethyl)-5-hydroxy-4H-pyran-4-one (4) with HBr in HOAc--phenol yielded 2-(aminomethyl)-5-hydroxy-4H-pyran-4-one (kojic amine, 3) in 81% yield. Reaction of 2-[(tosyloxy)-methyl]-5-(benzyloxy)-4H-pyran-4-one (5) with NH3 gave a 40% yield of the O-benzyl ether of kojic amine, which was N-acylated with a series of carbobenzyloxy-protected amino acids. Complete deprotection with HBr--HOAc gave the following amino acid amides of kojic amine: glycyl (23), alpha-alanyl (24), beta-alanyl (25), gamma-aminobutyryl (26), and glycylglycyl (27). Among the analogues of kojic amine prepared was a series of one-carbon homologues: 2-[(methylamino)methyl]-5-hydroxy-4H-pyran-4-one (7a), 2-(1-aminoethyl)-5-hydroxy-4H-pyran-4-one (8), 6-(aminomethyl)-3-hydroxy-2-methyl-4H-pyran-4-one (12), and 2-(2-aminoethyl)-5-hydroxy-4H-pyran-4-one (16). Kojic amine (3) has been found to possess certain of the properties to be expected in a gamma-aminobutyric acid mimetic agent, notably skeletal muscle relaxant activity. In the chronic spinal cat preparation, ED70 values for reduction of flexor spasms of 2.2 and 4.0 mg/kg by iv and po routes of administration, respectively, were observed for kojic amine, which was the most potent of the various hydroxypyrone derivatives investigated.

2-Pyrrolidinylideneureas, a new class of central nervous system agents

A series of N-aryl-N'-(1-methyl-2-pyrrolidinylidene)ureas was prepared and screened for pharmacological activity. Congeners possessing either phenyl or phenyl substituted with 4-nitro, 3-bromo, 3-chloro, 3-fluoro, and 3-methyl groups were found to demonstrate anxiolytic activity. 2,6-Disubstitution of the phenyl ring with methyl, chloro, and bromo imparted potent muscle-relaxant properties which appear to be centrally mediated. A significant separation of the anxiolytic and muscle-relaxant properties from other CNS activities, e.g., anticonvulsant, sedative, and hypnotic, was achieved.

Synthesis and comparative skeletal muscle relaxant activity of some 2,4-imidazolidinediones and their corresponding 5-hydroxy-2,4-imidazolidinediones

A series of 5-hydroxy substitution products of 2,4-imidazolidinediones, including the 5-hydroxy metabolite of the skeletal muscle contraction antagonist, dantrolene sodium, has been synthesized and evaluated for skeletal muscle relaxant activity. Most of these analogues are active in vivo with iv administration and in vitro. While two analogues are also active by oral and ip administration, only 1-[[[5-(3,4-dichlorophenyl)-2-furanyl]methylene]amino]-5-hydroxy-2,4-imidazolidinedione is sufficiently active in inhibiting the Straub tail in mice. However, none of these analogues has a muscle relaxant efficacy index greater than 1, comparable to dantrolene.