Synthesis and cytotoxicity of 1,2-disubstituted naphth[2,3-d]imidazole-4,9-diones and related compounds.

As part of our continuing search for potential anticancer drug candidates that are selective against slowly growing solid tumors, we have synthesized several series of 1- and 2-substituted derivatives of the lead structure, 1-ethyl-2-methylnaphth[2,3-d]imidazole-4,9-dione (5). Their cytotoxic activity in the National Cancer Institute's in vitro cancer cell line panel is reported. In general, substitution of various alkyl, phenyl, or benzyl moieties did not improve activity, and compound 5 remains the most active naphth[2,3-d]imidazole-4,9-dione derivative. However, high levels of activity and selectivity were found with several related 2-(acylamino)-3-chloro-1,4-naphthoquinones (2f-j). Compound 2i, 2-[(2-fluorophenyl)acetamido]-3-chloro-1,4-naphthoquinone, has been selected for further in vivo testing and as an additional lead compound for further structural modification.

Antitumor agents. 150. 2',3',4',5',5,6,7-substituted 2-phenyl-4-quinolones and related compounds: their synthesis, cytotoxicity, and inhibition of tubulin polymerization.

As part of our continuing search for potential anticancer drug candidates in the 2-phenyl-4-quinolone series, we have synthesized a series of 6,7-methylenedioxy-substituted and unsubstituted 2-phenyl-4-quinolones, as well as related compounds. Their in vitro inhibition of human tumor cell lines and tubulin polymerization is reported. In general, a good correlation was found between cytotoxicity and inhibition of tubulin polymerization. Compounds 7, 9, 13, 16, 22, 23, 36, and 37 showed potent inhibitory effects in both assays. All rigid analogs (47-49) and trimethoxy-substituted compounds showed little or no activity. Substitution at the 4'-position also resulted in compounds with little or no activity, except for hydroxyl or methyl groups at this position. Further investigation is underway to determine if substitution at the 3'-position will result in compounds with increased activity.

Synthesis of 2-methyl-(Z)-4-(phenylimino)naphth[2,3-d]oxazol-9-one , a monoimine quinone with selective cytotoxicity toward cancer cells.

A regio and stereospecific synthesis of 2-methyl-(Z)-4-(phenylimino)naphth[2,3-d]oxazol-9-one (1) was achieved by using titanium tetrachloride in methylene chloride in the preparation of the imine. The regiochemistry was assigned by single-crystal X-ray analysis. In vitro tests showed that this diastereomer is selectively active for some solid cancer tumors.

Synthesis and cytotoxicity of 1,6,7,8-substituted 2-(4'-substituted phenyl)-4-quinolones and related compounds: identification as antimitotic agents interacting with tubulin.

A series of 1,6,7,8-substituted 2-(4'-substituted phenyl)-4-quinolones and related compounds have been synthesized and evaluated as cytotoxic compounds and as antimitotic agents interacting with tubulin. The 2-phenyl-4-quinolones (22-30) with substituents (e.g. F, Cl, and OCH3) at C-6, C-7, and C-8 show, in general, potent cytotoxicity against human lung carcinoma (A-549), ileocecal carcinoma (HCT-8), melanoma (RPMI-7951), and epidermoid carcinoma of the nasopharynx (KB) and two murine leukemia lines (P-388 and L1210). Introduction of alkyl groups at N-1 or C-4 oxygen led to inactive compounds (35-43 and 50). In addition, compounds 24, 26, and 27 were evaluated in the National Cancer Institute's 60 human tumor cell line in vitro screen. These compounds demonstrated the most marked effects in the screen on two colon carcinoma cell lines (COLO-205 and KM-20L2) and on a central nervous system tumor cell line (SF-539) with compound 26 the most potent of the three agents. Compounds 24, 26, and 27 were potent inhibitors of tubulin polymerization, with activity nearly comparable to that of the potent antimitotic natural products colchicine, podophyllotoxin, and combretastatin A-4. The three agents also inhibited the binding of radiolabeled colchicine to tubulin, but this inhibition was less potent than that obtained with the natural products.

Comparative human study of ibuprofen enantiomer plasma concentrations produced by two commercially available ibuprofen tablets.

Twelve healthy male subjects participated in a two-way Latin square crossover study in which the treatments were a single 400 mg generic ibuprofen tablet (Tablet A) or a single 400 mg MOTRIN Tablet (Tablet B). Blood samples were drawn at various times through 12 h after dosing and plasma samples were assayed for ibuprofen enantiomers with a stereospecific capillary gas chromatographic procedure. Concentration-time data for both enantiomers were in agreement and indicated that drug was absorbed much more quickly from Tablet B than from the Tablet A; enantiomer Tmax values were less than 1.3 h from Tablet B but longer than 4 h from the Tablet A (p less than 0.001). Also, maximum enantiomer plasma concentrations from the Tablet B were about 50 per cent of the peak concentrations observed from Tablet A (p less than 0.001). The total extent of drug absorption appeared to be the same in both products. These data clearly indicate that the two tablets are not bioequivalent with respect to either ibuprofen enantiomer.

Exploration of a chemical series as a drug discovery strategy.

Thought process common to many medicinal chemists are exposed in this example dealing with the quest for the discovery of new analgesic agents. The unexpected course of a chemical reaction, and subsequent random screening of the product, led to the serendipidous finding of CNS activity in the phenylcyclohexylamine derivative (9). In the development of the lead, synthetic targets were continually adjusted as the result of subsequent biological testing, and finally produced two compounds (34 and 35) with clinical potential as analgetics. Each failed to enter clinical testing due to their toxicity, but the overall results led to new concepts of the nature of the mu opioid receptor.

Total chemical synthesis and antitumor evaluation of 4-demethoxy-10,10-dimethyldaunomycin.

The novel anthracycline analogue 4-demethoxy-10,10-dimethyldaunomycin was prepared in nine chemical steps from 5,8-dimethoxy-2-tetralone. It proved to be inactive as an antitumor agent in the mouse P388 lymphocytic leukemia model.

4-amino-4-arylcyclohexanones and their derivatives: a novel class of analgesics. 2. Modification of the carbonyl function.

The effect on potency of modification of the carbonyl function of analgesics derived from 4-(dimethylamino)-4-arylcyclohexan-1-one was studied by reduction and by addition of nucleophiles. The resulting amino alcohols were separated and assigned structures on the basis of X-ray crystallography, NMR, and TLC mobility. The trans (OH and N) isomers were invariably more potent than the cis. Inclusion of flat lipophilic moieties (phenyl, cyclohexenyl) at a distance of at least two carbon atoms from the carbon bearing hydroxyl led to increases in potency by orders of magnitude. The possible significance of this on receptor interaction is discussed.

4-aryl-4-aminocyclohexanones and their derivatives, a novel class of analgesics. 3. m-Hydroxyphenyl derivates.

Derivatives of 4-aryl-4-(dimethylamino)cyclohexan-1-ones substituted by m-hydroxy groups were obtained by using as a key reaction the displacement of cyanide from the alpha-aminonitrile of 1,4-cyclohexanedione ketal, with the THP ether of m-hydroxyphenylmagnesium bromide. A number of the products show narcotic antagonist activity. Amino alcohols obtained on reaction of the free ketones with phenethyl Grignard reagents are potent analgetics, though devoid of antagonist activity. Systematic variation of the substituent on nitrogen revealed nonclassical structure-activity relationships; the dimethylamino group gives the most potent antagonist.

4-Amino-4-arylcyclohexanones and their derivatives, a novel class of analgesics. 1. Modification of the aryl ring.

Investigation of central nervous system activity of phenylcyclohexylamines was continued by preparation of "reversed" analogues. Following the unexpected finding of analgesic activity with 1-(dimethylamino)-1-phenylcyclohexylamine, the SAR of the series was investigated. Synthesis starts by double Michael reaction of acrylate on arylacetonitriles. Following cyclization, decarboxylation, ketalization, and saponification, the geminally substituted acid is rearranged to the isocyanate by means of (C6H5O)2PON3. Isocyanates were then converted to the title compounds. Analgesic activity is very sensitive to the nature and position of the substitutent on the aromatic ring. The most potent compounds in this series (p-CH3, p-Br) showed 50% the potency of morphine. Deletion of the ring oxygen abolishes activity.

Hypobetalipoproteinemic agents. 2. Compounds related to 4-(1-adamantyloxy)aniline.

While the previously used displacement reaction of sodim 1-adamantyl oxide on 4-fluoronitrobenzene was applicable to the preparation of 4-(1-adamantyloxy)aniline and several related compounds, certain derivatives were not easily accessible by this route. Thus the recently reported ortho alkylation of anilines and the dicyclohexylcarbodiimide-promoted coupling of 1-adamantanol with phenols were useful in the preparation of aromatic-substituted derivatives. Furthermore, addition of phenylmagnesium bromide to 1-cyanoadamantane provided entry to the 4-(1-adamantylmethyl)aniline series. 4-(1-Adamantyloxy)aniline (3) is herein reported to be a more potent hypobetalipoproteinemic agent than the previously reported bicyclooctyloxy analogue. Replacement of the oxygen atom of 3 with sulfur (74) or methylene (62), but not nitrogen (71), results in active compounds. In the oxygen series derived from 3, the widest scope of substitution on nitrogen resulting in activity is found. The N-ethoxycarbonyl (5), acetyl (6), methyl (12), ethyl (13), N-methyl-N-(2-hydroxyethyl) (19), N-methyl-N-formyl (22), N,N-dimethyl (26), pyrrolidine (14), and piperidine (15) derivatives are active. Aromatic ring substitution also provided the active 3-chloro (44b), 2-fluoro (41b, 42, and 43), and 2-methylthiomethyl (48) compounds. Thus these active compounds are identified for further development as hypobetalipoproteinemic agents.

Butyrophenones from the isomeric 2-amino-5-phenylbicyclo[3.3.1]nonanes.

The preparation of 5-phenylbicyclo [3.3.1]nonan-2-one is described starting from the ketal of 4-phenyl-4-(2-carbethoxyethyl)cyclohexan-1-one. The ketone was then taken on to the butyrophenone derivatives of endo-and exo-5phenylbicyclo[3.3.1]nonyl-2-amine. CNS screening results of these compounds are described.

Biological activity of a hypobetalipoproteinemic agent.

A new -ind of pharmacologic activity called hypobetalipoproteinemia is described. Iperationally the activity consists of a marked reduction of heparin precipitating lipoproteins (beta and/or pre-beta electrophoretic mobility) in hypercholesterolemic animals with a simultaneous decrease in the heparin precipitating lipoprotein: cholesterol ratio. As determined by ultracentrifugal fractionation of the lipoproteins from hypercholesterolemic rat serum, this activity consists of both a reduction in heparin precipitating lipoproteins and an increase high density lipoproteins that are not precipitated by heparin. Changes in composition were also induced in both lipoprotein fractions. The greatest changes were observed for free and esterified cholesterol, which were markedly reduced in the heparin precipitating lipoproteins and concomitantly increased in the high density lipoproteins. The hypobetalipoproteinemic agent exhibiting this activity is 1-[p-(1'-adamantyloxy) phenyl]-piperidine (U-41792). This agent is active in hypercholesterolemic rats, mice, quail, and pigeons.

Hypo-beta-lipoproteinemic agents. 1. Bicyclo[2.2.2]octyloxyaniline and its derivatives.

A new assay for agents which normalize beta-lipoproteins in cholesterol-cholic acid fed rats is described. Both lowering of serum cholesterol and of serum heparin precipitable lipoproteins (HPL) were measured at the end of the treatment period. Compounds which shifted the ratio of the decrease in favor of HPL are considered hypo-beta-lipoproteinemic. p-(1-Bicyclo[2.2.2]octyloxy)aniline and several of its derivatives proved active in this assay. The synthesis of these compounds is described.

Butyrophenones as hypotensive agents. Derivatives of 4-aryl-4-(hydroxymethyl)cyclohexylamine.

The preparation of butyrophenone derivatives of 4-aryl-4-(hydroxymethyl)cyclohex-1-ylamines starting from the corresponding 4-cyano-4-phenylcyclohexan-1-ones is described. Substitution was varied with both rings; both isomers of 4-phenyl-4-(hydroxymethyl)cyclohex-1-ylamine were characterized. Those derivatives which carried p-fluoro substitution on the butyrophenone exhibited hypotensive activity in the rat with diminished CNS activity compared to compounds lacking the hydroxymethyl group. The effect of substitution on the 4-aryl ring is discussed.