RU2174116C2 - Substituted benz[a]acridines, pharmaceutical composition, therapeutic method of inhibition of cancer cell proliferation - Google Patents

Abstract

FIELD: organic chemistry, pharmacy. SUBSTANCE: invention relates to novel substituted benz[a]acridines of the formula (II)

where R₁ and R₂ mean independently OH, NO₂,NH₂, halogen atom, NHCO-(C₁- C₈)-alkyl or (C₁- C₈)-alkoxy-group; or R₁ and R₂ mean in common -OCH₂O-; R₃ means H; R₅ and R₆ means independently H, OH, NO₂,NH₂, halogen atom, NHCO-(C₁- C₈)-alkyl or (C₁- C₈)-alkoxy-group; or R₅ and R₆ in common mean -OCH₂O and R₇ means H or (C₁- C₈)-alkyl; or R₁,R₂,R₃,R₅,R₆ mean independently H, OH, NO₂,NH₂, halogen atom, NHCO-(C₁- C₈)-alkyl or (C₁- C₈)-alkoxy-group; R₂ and R₃ in common mean -OCH₂O-; R₅ and R₆ mean in common -OCH₂O- and R₇ means H or

-alkyl under condition that one of R₁ and R₂ means (C₁- C₈)-alkoxy-group; or R₁ and R₂ in common mean -OCH₂O-; or R₁,R₅,R₆ mean independently H, OH, NO₂,NH₂, halogen atom, NHCO-(C₁- C₈)-alkyl or (C₁- C₈)-alkoxy-group; R₂ and R₃ in common means -OCH₂O- and R- means H or (C₁- C₈)-alkyl, or its pharmaceutically acceptable salts. Also, invention relates to the more specific compounds, pharmaceutical composition that is able to inhibit cancer cells proliferation and involving the above indicated compounds and therapeutic method of inhibition of cancer cells proliferation involving administration of these compounds. EFFECT: new compounds indicated above, valuable anticancer properties. 22 cl, 4 dwg, 2 tbl, 13 ex

Description

 DNA topoisomerases are enzymes that are present in the nuclei of cells, where they catalyze breaks and reunification of DNA strands that control the topological state of DNA. Recent studies also suggest that topoisomerases are also involved in the regulation of the formation of template supercoils during RNA transcription. There are two main classes of mammalian topoisomerases. DNA topoisomerase-I catalyzes changes in the topological state of double DNA by performing temporary single-stranded break-compound cycles. In contrast, the mammalian topoisomerase II alters the DNA topology due to the fact that it causes a temporary break in the double strand connected by the enzyme bridge, followed by the transition and sealing of the strands. The mammalian topoisomerase II was further classified as type IIα and type IIβ. The antitumor activity associated with substances that are topoisomerase poisons (topoisomerase poisoning agents) is associated with their ability to stabilize a cleavable enzyme-DNA complex. This drug-induced stabilization of the cleavable enzyme-DNA complex turns the enzyme into cell poison.

 Several antitumor substances in clinical use have potential activity as mammalian topoisomerase II poisons. This includes adriamycin, actinomycin D, daunomycin, VP-16 and VM-26. In contrast to the many clinically used and experimental drugs that act as topoisomerase II poisons, there is currently only a limited number of substances that have been identified as topoisomerase I poisons. The most intensively studied topoisomerase I poisons are camptothecin and its structurally similar analogues. Recently, bi- and terbenzimidazoles have been identified as topoisomerase I poisons (Chen et. Al., Cancer Res. 1993, 53, 1332-1335; Sun et al., J. Med. Chem. 1995, 38, 3638-3644 ; Kim et al., 1996, 39, 992-998), some benzo [c] phenanthridine and protoberberine alkaloids and their synthetic analogues (Makhey et al., Med. Chem. Res. 1995, 5, 1-12; Janin et al., J. Med. Chem. 1975, 18, 708-713; Makhey et al., Bioorg. & Med. Chem. 1996, 4, 781-791), as well as fungal metabolites, bulgarin (Fujii et al., J. Biol. Chem. 1993, 268, 13160-13165) and saintopin (Yamashita et al. Biochemistry 1991, 30, 5838-5845) and indolocarbazoles (Yamashita et al., Biochemistry 1992, 31, 12069-12075).

 The exceptional poisoning of topoisomerase in the case of coraline, nitidine, 5,6-dihydro-8-desmethylcoraline and related analogues has led to several recent studies of those structural characteristics that are related to their ability to specifically act as poisons of topoisomerase I and topoisomerase II (Gatto et al., Cancer Res. 1996, 56, 2795-2800; Wang et al., Chem. Res. Toxicol. 1996, 9, 75-83; Wang et al., Chem. Res. Toxicol. 1993, 6, 813-818). A common feature characteristic of all these substances is the presence of a 3-phenylisoquinolinium fragment inside their structure.

 Despite the observations showing that some of these compounds have activity similar to camptothecin as topoisomerase I poison, or activity similar to VM-26 as topoisomerase II poison, they have only a slight cytotoxic activity. The absence of a more direct correlation with their activity as topoisomerase poisons is partly explained by the likelihood that these substances are apparently not absorbed as efficiently by cells as camptothecin or VM-26. It is most likely that the presence of the Quaternary ammonium group inhibits cellular uptake. It has been found that to ensure efficient transport of substances such as coral and nitidine, hydrolysis with subsequent dehydration or cyclodehydration may be required to reform the starting quaternary ammonium compound. This may explain the relatively low antitumor activity observed in vitro with agents such as coraline or nitidine.

 Clearly, there is a need for anti-cancer agents with improved activity.

(I)
где R₁, R₂, R₃, R₅ и R₆ независимо представляют H, ОН, NO₂, NH₂, галоген, NHCO(C₁-C₈)алкил или (C₁-C₈)алкокси; R₁ и R₂ вместе представляют -OCH₂O-; R₂ и R₃ вместе представляют -OCH₂O-; или R₅ и R₆ вместе представляют -OCH₂O-;
R₄ и R₇ независимо представляют H, (C₁-C₈) алкил или отсутствуют;
W представляет C или N;
X представляет C или N;
Y представляет -C= , -N= или прямую связь, при условии, что, когда Y представляет -C=, то X представляет N; и
Z представляет -CH=CH-, -(CH₂)₂- или отсутствует; или их фармацевтически приемлемые соли.SUMMARY OF THE INVENTION
The present invention provides compounds of formula (I)

(I)
where R ₁ , R ₂ , R ₃ , R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy; R ₁ and R ₂ together represent —OCH ₂ O—; R ₂ and R ₃ together represent —OCH ₂ O—; or R ₅ and R ₆ together represent —OCH ₂ O—;
R ₄ and R ₇ independently represent H, (C ₁ -C ₈ ) alkyl or are absent;
W represents C or N;
X represents C or N;
Y represents —C =, —N = or a direct bond, provided that when Y represents —C =, then X represents N; and
Z represents —CH = CH—, - (CH ₂ ) ₂ - or is absent; or their pharmaceutically acceptable salts.

 According to one preferred embodiment of the invention, W represents N and Y represents a direct bond. In another preferred embodiment, W is C, and Y is —C = or —N =.

According to another preferred embodiment of the invention, Z is —CH═CH— or - (CH ₂ ) ₂ -. In another preferred embodiment, R ₅ and R ₆ each represents (C ₁ -C ₈ ) alkoxy, preferably —OCH ₃ , or together they represent —OCH ₂ O—. Preferably R ₃ is H. In a preferred embodiment of the invention, one or both of R ₁ , R ₂ is (C ₁ -C ₈ ) alkoxy, preferably —OCH ₃ , or together represent —OCH ₂ O—. In another preferred embodiment, R ₂ and R ₃ together represent —OCH ₂ O—.

Preferably, when X is C, R ₇ is H, methyl or ethyl; or when X is C, R ₇ is H. Preferably, when X is N, R _{7 is} absent or is CH ₃ . Similarly, preferably, when Y is —C═, R ₄ is H; and when Y is —N =, R _{4 is} absent or is CH ₃ . It is understood that when X or Y represents a substituted N, then N will have a positive charge.

(II)
где R₁, R₂, R₃, R₅, R₆ и R₇ имеют любое из значений или из предпочтительных значений, указанных здесь для соединения формулы I; или их фармацевтически приемлемые соли.A preferred group of compounds of formula I are compounds of formula II

(Ii)
where R ₁ , R ₂ , R ₃ , R ₅ , R ₆ and R ₇ have any of the meanings or from the preferred meanings indicated herein for a compound of formula I; or their pharmaceutically acceptable salts.

 The compounds of formula (I) have been shown to be effective cytotoxic agents against cancer cells, including drug resistant cancer cells. In addition, some compounds of formula I exhibit inhibitory activity against topoisomerase I.

 Thus, the present invention also provides a method of inhibiting the growth of cancer cells in vitro or in vivo, comprising administering to a cancer-affected mammal an amount of a compound of formula (I) effective to inhibit the growth of said cancer cells. In accordance with this invention, the compound or its salt may be administered in combination with a pharmaceutically acceptable carrier.

 The invention also relates to pharmaceutical compositions comprising a compound of this invention in combination with a pharmaceutically acceptable carrier, as well as methods for preparing compounds of this invention and new intermediates useful for the synthesis of compounds of this invention.

Brief Description of the Drawings
FIG. 1 illustrates the synthesis of the characteristic benz [c] acridines of formula (I).

 FIG. 2 illustrates the synthesis of the characteristic benz [c] acridines of formula (I).

 FIG. 3 illustrates the synthesis of representative compounds of the present invention.

 FIG. 4 illustrates the synthesis of intermediates useful in the preparation of compounds of formula (I).

DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, cancer cells, cancer cells are inhibited in vitro and in vivo by administering to a cancer-affected mammal an effective amount of a compound of formula (I). By the expression “effective amount” as used herein is meant that amount which inhibits the growth of the cancer cells against which it is directed. As described herein, a suitable dose is in the range of about 0.5 to 100 mg / kg body weight per day.

 The compounds and compositions described herein are effective for treating mammalian solid tumors and malignant blood diseases. These solid tumors include cancer of the head and neck, lungs, mesothelioma, cancer of the mediastinum, esophagus, stomach, pancreas, renal and bile system, small intestine, colon, rectum, anus, kidney, ureter, bladder, prostate, urethra, penis, testis, female genital organs, ovaries, mammary gland, endocrine system, skin, central nervous system; sarcoma of soft tissues and bones; as well as melanomas of skin and intraocular origin. Malignant blood diseases include childhood leukemia and lymphomas, Hodgkin's disease, lymphomas of lymphocytic and cutaneous origin, acute and chronic leukemia, cell and plasma neoplasm, and AIDS-related cancer. Preferred mammals for treatment are humans and domestic animals.

Benz [c] acridines of formula I (X is N, and Y is —C =) can conveniently be prepared by the method illustrated in FIG. 1. Reaction of 2-amino-4,5-dimethoxyacetophenone, 4, with 6,7-dimethoxy- 1-tetralone, 5, gives 5,6-dihydro-2,3,9,10-tetramethoxybenz [c] acridine, 6 which, when heated as a suspension in decaline at 190 ^° C in the presence of palladium on charcoal, can turn 2,3,9,10-tetramethoxybenz [s] acridine, 7. Both 6 and 7 can be converted to their 12-methyl derivatives by reaction with dimethyl sulfate, resulting in the formation of quaternary salts mmoniya, 8 and 9 respectively.

Analogs of benz [a] acridine (X represents C, a Y represents —N =) can be obtained using techniques similar to those illustrated in Figure 2. Knoevenagel condensation of the corresponding o-nitrobenzaldehyde with 5,6- or 6,7-disubstituted β- tetralones, gives 1- (2'-nitrobenzene) -2-tetralones, 12a-f and j. Reduction with zinc in acetic acid gives the desired derivatives of 5,6-dihydrobenz [a] acridine, 13a-f and j. Heating in decalin at 190 ^o C in the presence of palladium on charcoal leads to the conversion of these compounds to their benzo [a] acridine derivatives, 14a-d and j. Treatment of either 13a or 14a with BBr ₃ (boron tribromide) in methylene chloride gives tetrahydroxy analogs, 13g and 14g, respectively. The reaction of 13a or 14a with dimethyl sulfate leads to the formation of their 7-methyl derivatives, 15a and 16a.

 Starting materials, 2-nitro-4,5-dimethoxybenzaldehyde and 2-nitro-4,5-methylenedioxybenzaldehyde are commercially available. The preparation of 6-chloro-β-tetralone can be performed as described by Rosowsky et al., J. Org. Chem. 1968, 33, 4288-4290 (Rozovsky et al., MLC).

 7-Nitro-β-tetralone was obtained from 7-nitro-α-tetralone using a procedure similar to that described by Nichols et al. (Organic Preparations and Procedures 1977, 277-280), as illustrated in Figure 3. 7-Nitro-β-tetralone served as an intermediate in the preparation of compounds 20, 21, 22 and 23, as shown in Figure 3.

 5,6-Methylenedioxy-2-tetralone (11e) was used as a necessary intermediate to obtain 5,6-dihydro-9,10-dimethoxy-3,4-methylenedioxybenz [a] acridine, 13e. This tetralone was prepared in six stages, as shown in Figure 4. 2,3-Methylenedioxybenzaldehyde condensed with malonic acid to give 2,3-methylenedioxycinnamic acid (J. Koo et al., Org. Synthesis Coll. Vol. IV, 1963, 327 -329). 2,3-Methylenedioxycinnamic acid was hydrogenated using 10% palladium-carbon to give a dihydrocinnamic acid derivative, which was then transformed into its ethyl ester, 17 (M.A. Brook; TN Chan, Synthesis Comm., 1983, 201-203 ) Ethyl 2,3-methylenedioxyhydrocinnamate was then converted to its β-ketosulfoxide, 18, (J. G. Cannon et al., J. Med. Chem., 1977, 20, 1111-1116). The β-ketosulfoxide derivative, 18, when subjected to Pummerer rearrangement by treatment with trifluoroacetic acid, afforded 1,2,3,4-tetrahydro-1-methylthio-5,6-methylenedioxy-2 (1H) -naphthalenone, 19 (Y. Oikawk , Tetrahedron, 1974, 30, 2653-2660). Hydrogenolysis of compound 19 using 10% palladium on carbon in glacial acetic acid gave compound 11e (D.E. Nicholes, J. Med. Chem. 1990, 33, 703-710).

Pharmaceutically acceptable salts of the compounds of formula I can also be used in the practice of the claimed methods. Pharmaceutically acceptable salts may be prepared using organic and inorganic bases such as NaOH, Na ₂ CO ₃ , NaHCO ₃ , KOH and the like; as well as acids such as hydrochloric acid, sulfoacetic acids and the like. Although the compounds and / or salts described herein can be administered as pure chemicals, it is preferable to provide the active ingredient as a pharmaceutical composition. The present invention also relates to the use of a pharmaceutical composition (composition) comprising one or more compounds and / or pharmaceutically acceptable salts, together with one or more pharmaceutically acceptable carriers, and, optionally, other therapeutic and / or prophylactic ingredients. The carrier (s) must be "acceptable" in the sense that it (they) must be compatible with the other ingredients of the composition and should not (should not) be harmful to the recipient.

 Pharmaceutical formulations (compositions) include those suitable for oral administration and for parenteral administration (including intramuscular, subcutaneous and intravenous administration). These formulations may, when convenient, be presented in separate or discrete unit dosage forms and may be prepared by any of the methods well known to those skilled in the art of pharmacology. Such methods include mixing the active substance with liquid carriers, with solid matrices, semi-solid carriers, with finely divided solid carriers or a combination thereof, and then, if necessary, shaping the product in accordance with the desired drug delivery system.

 Pharmaceutical formulations suitable for oral administration may be presented in unit dosage form, such as hard or soft gelatine capsules, starch capsules or tablets, each containing a specific dose of the active ingredient; in the form of powder or granules; in the form of a solution, suspension or emulsion. The active ingredient may also be presented as a bolus (ball), electuary (medicinal porridge) or paste. Tablets and capsules for oral administration may contain conventional additives, such as binders, fillers, lubricants, disintegrants or wetting agents. The tablets may be coated in accordance with methods well known to those skilled in the art, for example, enteric coating.

 Oral liquid preparations may, for example, be in the form of an aqueous or oily suspension, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for constitution with water or other suitable vehicles before use. Such liquid preparations may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous vehicles (which may include edible oils) or preservatives.

 The compounds may also be presented in parenteral dosage forms (e.g., by injection; e.g., by bolus or continuous infusion) or may be presented in unit doses in ampoules pre-filled with syringe medicine, as infusion containers for small boluses or in the form of containers with many doses, with the addition of preservatives. These formulations may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain agents customary in the manufacture of drugs, such as suspending, stabilizing and / or dispersing agents. Alternatively, the active ingredient may be in the form of a powder, obtained by aseptic isolation of a sterile solid or by lyophilization from a solution, for mixing before use with suitable carriers, for example sterile, pyrogen-free water.

 For topical or topical application to the epidermis, formulations can be formulated as ointments, creams or lotions, or as an active ingredient in a transdermal patch. Suitable transdermal delivery systems are described, for example, in US Pat. Nos. 4,788,603 (Fisher et al.) Or Nos. 4,931,279, 4,668,504 and 4,713,224 (Bawas et al). Ointments and creams can, for example, be made in the form of a water or oil based drug, with the addition of suitable thickening agents and / or gelling agents. Lotions can be made in the form of medicines with a water or oil base, usually containing one or more emulsifying agents, stabilizing agents, dispersing agents, suspending agents, thickening agents or coloring agents. The active ingredient can also be delivered to the patient by iontophoresis, for example, as described in US patent N 4140122, 4383529 or 4051842.

 Formulations suitable for topical administration in the mouth include unit dosage forms, such as lozenges, comprising the active ingredient based on flavors, usually with sucrose or with acacia or with tragacanth; lozenges comprising the active ingredient in an inert basis such as gelatin and glycerin or sucrose and acacia; gels adhering to the mucous membrane, as well as mouthwashes including the active ingredient in a suitable liquid carrier.

 If desired, the above compositions can be adapted in order to provide a sustained release of the active ingredient used, for example, by combining it with certain hydrophilic polymer matrices, for example, including natural gels, synthetic polymer gels, or mixtures thereof.

 The pharmaceutical compositions in accordance with the present invention may also contain other excipients, such as flavorings, coloring agents, antimicrobial agents or preservatives.

 In addition, it should obviously be understood that the amount of the compound or its active salt or its derivative required for use in the treatment will vary not only depending on the particular salt selected, but also on the route of administration, the nature of the condition being treated, and also on the age and condition of the patient, and this number is ultimately selected by the attending physician.

 Usually, however, a suitable dose is in the range of from about 0.5 to 100 mg / kg, for example, from about 10 to 75 mg per kilogram of body weight per day, or for example from 3 to 50 mg per kilogram of body weight of the recipient, preferably in a range of 6 to 90 mg / kg / day, most preferably a range of 15 to 60 mg / kg / day.

 The compound is conveniently administered in unit dosage form, for example, containing from 5 to 1000 mg, more conveniently from 10 to 750 mg, most conveniently from 50 to 500 mg of the active ingredient per unit dose.

 Ideally, the active ingredient should be administered so as to reach a peak plasma concentration of the active compound from about 0.5 to 75 μM, preferably from about 1 to 50 μM, most preferably from about 2 to about 30 μM. This can be achieved, for example, by intravenous administration of a 0.05-5% solution of the active ingredient, optionally in saline (physiological) solution, or by oral administration in the form of a bolus containing about 1-100 mg of the active ingredient.

 Desired drug levels in the blood can be maintained by continuous infusion providing about 0.01-5.0 mg / kg / hr, or by intermittent infusions containing about 0.4-15 mg / kg of active ingredient (s).

 The desired dose can conveniently be presented in the form of a single (single) dose or in the form of divided doses administered at certain intervals, for example, in the form of two, three, four or more sub-doses per day. This sub-dose itself can also be further divided, for example, into a series of arbitrarily divided administrations; such as repeated inhalations from an insufflator or by applying a lot of drops instilled into the eye.

 The invention is illustrated by, but is not limited to, the following examples.

EXAMPLES
EXAMPLE I - General
Melting points were determined using a Thomas-Hoover capillary instrument to determine the melting point. The spectral data of infrared radiation (IR) were obtained on a Perkin-Elmer 1600 Fourier transform spectrophotometer and are presented in cm ^-1 . Proton ( ¹ H NMR) and carbon nuclear magnetic resonance ( ¹³ C NMR) were recorded using a Varian-Gemini-200 Fourier transform spectrometer. NMR spectra (200 MHz ¹ H and 50 MHz ¹³ C) were recorded in CDCl ₃ (with the exception of special cases), with chemical shifts, expressed in units of δ, towards a weak field from tetramethylsilane (TMS). The interaction constants are expressed in hertz. Mass spectra were obtained from data on biomedical and bioorganic spectrometry of the University of Washington. Column chromatography refers to flash chromatography carried out on SiTech 32-63 μm (ICN Biomedicals, Eschwegge, Germany) using these solvent systems. Combustion analyzes were conducted by Atlantic Microlabs Inc., Norcross, Georgia, and their results were within ± 0.4%.

2,3,9,10-Tetramethoxy-7-methyl-5,6-dihydrobenz [c] acridine (6). 2-amino-4,5-dimethoxyacetophenone (1.0 g, 5.1 mmol) was dissolved in 10 ml of CH ₂ Cl ₂ and hydrogen chloride (1.0 M solution of anhydride in ether) was added with vigorous stirring at room temperature. The hydrochloride salt of aminoacetophenone precipitated. The solvent was removed in vacuo and the resulting solid precipitate was dried in vacuo for one hour. The dry hydrochloride salt was then ground in a mortar with 6,7-dimethoxy-1-tetralone (1.59 g, 7.68 mmol), and then the mixture was transferred to a sealed tube and heated at 140 ^° C. for 1 hour. The resulting molten plug was then dissolved in boiling methanol (300 ml). This solution was then concentrated to 200 ml and left overnight to give needle crystals. The crystals were filtered off, washed with three portions (5 ml) of acetone, and dried to give golden yellow needles of the benz [c] acridine hydrochloride derivative in 99% yield. The hydrochloride salt was dissolved in 200 ml of boiling methanol. After the solution was cooled to room temperature, concentrated NH ₄ OH was added dropwise until a pH of 10 was obtained. Light yellow crystals began to form. The suspension was then diluted with 200 ml of water and extracted three times with 100 ml portions of CH ₂ Cl ₂ . The combined extracts were washed once with 50 ml of brine, dried with anhydrous Na ₂ SO ₄ , filtered, and the solvent was removed in vacuo to give a free base; so pl. 240 ^o C; IR (nujol): 2922, 1620; ¹ H NMR: δ 2.52 (3H, s), 2.86 (2H, s), 3.02 (2H, t), 3.90 (3H, s), 3.98 (3H , s.), 4.03 (3H, s.), 4.05 (3H, s.), 6.70 (1H, s.), 7.08 (1H, s.), 7.43 (1H , s.), 8.04 (1H, s.); ¹³ C NMR: δ 16.5, 25.4, 28.0, 56.6, 56.7, 57.8, 58.3, 102.3, 102.7, 110.9, 111.8, 119 5, 123.2, 127.7, 134.7, 135.6, 146.3, 148.5, 149.7, 151.3, 151.5 155.2; HRMS (high resolution mass spectrometry): calculated for C ₂₂ H ₂₃ NO ₄ : 365.1630; Found: 365.1628.

5,6-Methylenedioxy-2-tetralone (11e): 0.669 g (2.83 mmol) of compound 19 was taken in 10 ml of glacial acetic acid in a hydrogenation flask. 0.46 g of 10% palladium on carbon was added and the mixture was shaken in a Parr apparatus at a hydrogen pressure of 40 psi (275.7904 Pa) for 40 hours. The reaction mixture was filtered through a pad of celite, which was washed three times with 5 ml portions of glacial acetic acid. Glacial acetic acid was rotary evaporated to give crude tetralone, 11e. The crude tetralone was then treated with sodium bisulfite to convert it to a more stable adduct (adduct) of bisulfite. Pure tetralone was obtained from its bisulfite adduct by treatment with a 10% sodium carbonate solution, followed by extraction with dichloromethane; t. pl. 90-91 ^o C (lit. ³⁶ 88-91 ^o C); IR (nujol), 1715; ¹ H NMR: δ 2.50 (2H, t), 2.98 (2H, t), 3.50 (2H, s), 5.93 (2H, s), 6.56 (1H, d. J = 6), 6.65 (1H, d. J = 6); ¹³ C NMR: δ 21.6, 37.9, 45.0, 101.5, 107.4, 118.5, 121.1, 127.8, 144.1, 146.2, 211.2; Anal (C ₁₁ H ₁₀ O ₃ ) C, H.

 EXAMPLE II - General procedure for the synthesis of derivatives of 1- (2'-nitrobenzylidene) -2-tetralone (figure 2).

 A solution of 2.45 mmol of the corresponding 2-tetralone, 2-nitrobenzaldehyde and sodium acetate in glacial acetic acid (10 ml) was heated under reflux in a nitrogen atmosphere for 3-8 hours. Then the reaction mixture was allowed to cool to room temperature. The mixture was carefully passed through a silica gel (75 g) column and chromatographed using a mixture of ethyl ether and hexanes (1: 1). The yellow-colored compound, usually eluting fourth from the column, was collected to give the corresponding tetralone derivatives in 20-25% yield.

1- (2'Nitro-4 ', 5'-dimethoxybenzylidene) -6,7-dimethoxy-2-tetralone (12a). Obtained from 6,7-dimethoxy-2-tetralone and 6-nitroveraraldehyde; t. pl. 65-66 ^o C; IR (nujol), 2855, 1720, 1540; ¹ H NMR: δ 2.71 (2H, t), 2.98 (2H, t), 3.35 (3H, s), 3.66 (3H, s), 3.89 (3H, s.), 3.97 (3H, s.), 6.41 (1H, s.), 6.62 (1H, s.), 6.73 (1H, s.), 7.74 (1H, s.), 7.91 (1H, s.); ¹³ C NMR: δ 28.4, 39.7, 56.5, 56.6 56.8, 56.9, 107.7, 108.6, 111.2, 113.1, 128.1, 129, 3, 130.3, 132.2, 133.3, 148.9, 149.0, 150.0, 153.3, 200.7.

1- (2'-Nitro-4 ', 5'-dimethylenedioxybenzylidene) -6,7-dimethoxy-2-tetralone (12b). Derived from 6,7-dimethoxy-2-tetralone and 6-nitropiperonal; melting point 76-77 ^o C; IR (nujol): 2875, 1723, 1553; ¹ H NMR: δ 2.68 (2H, t), 3.00 (2H, t), 3.41 (3H, s), 3.90 (3H, s), 6.08 (2H , s.), 6.37 (1H, s.), 6.51 (1H, s.), 6.73 (1H, s.), 7.68 (1H, s.), 7.83 (1H , p.), ¹³ C NMR: δ 28.0, 38.0, 56.1, 56.4, 103.7 105.9, 110.1, 111.3, 112.6, 124.3, 130 8, 131.1, 132.2, 133.8, 147.6, 148.4, 149.7, 152.5.

1- (2'-Nitro-4 ', 5'-dimethoxybenzylidene) -2-tetralone (12c). Derived from 2-tetralone and 2-nitro-4,5-dimethoxybenzaldehyde; melting point 58-60 ^o C; IR (nujol): 1724, 1540; ¹ H NMR: δ 2.71 (2H, t), 3.08 (2H, t), 3.56 (3H, s), 4.02 (3H, s), 6.51 (1H, s.), 6.92-6.96 (2H, m.), 7.17-7.24 (2H, m.), 7.73 (1H, s.), 8.00 (1H, s. ); ¹³ C NMR: δ 28.3, 27.8, 56.7, 56.9, 108.3, 112.5, 126.7, 127.6, 128.5, 128.8, 129.9, 132 3, 133.4, 134.5, 138.8, 141.6, 149.4; 153.5.

 1- (2'-Nitrobenzylidene) -6,7-dimethoxy-2-tetralone (12d).

Derived from 6,7-dimethoxy-2-tetralone and 2-nitrobenzaldehyde; melting point 63-64 ^o C; IR (nujol): 1712, 1540; ¹ H NMR: δ 2.69 (2H, t), 3.01 (2H, t), 3.25 (3H, s), 3.88 (3H, s), 6.26 (1H , s.), 6.72 (1H, s.), 7.25-7.26 (1H, m.), 7.44-7.50 (2H, m.), 7.87 (1H, s .), 8.12-8.17 (1H, m.); ¹³ C NMR: δ 28.0, 37.9, 55.7, 56.3, 108.6, 111.3, 112.5, 124.2, 124.9, 125.4, 129.3, 130 1, 131.8, 133.5, 133.9, 134.7, 147.5; 149.6, 200.7.

1- (2'-Nitro-4 ', 5'-dimethoxybenzylidene) -5,6-methylenedioxy-2-tetralone (12e). Derived from 5,6-methylenedioxy-2-tetralone and 2-nitro-4,5-dimethoxybenzaldehyde; melting point 66-68 ^o C; IR (nujol): 1710, 1533; ¹ H NMR: δ 2.98 (2H, t), 3.19 (2H, t), 4.02 (3H, s), 4.03 (3H, s), 6.03 (2H , s.), 6.82 (1H, d, J = 8.1), 7.07 (1H, s.), 7.29 (1H, d, J = 8.1), 7.49 (1H, s.), 8.20 (1H, s.); ¹³ C NMR: δ 21.8, 30.8, 56.5, 56.7, 101.8, 105.7, 107.6, 117.9, 119.1, 123.9, 125.9, 126 9, 128.7, 143.4, 145.4, 147.7, 150.1; 152.9, 156.1, 176.4; Anal (C ₂₀ H ₁₇ NO ₇ ) C, H, N.

1- (2'-Nitro-4 ', 5'-dimethoxybenzylidene) -5,6-dimethoxy-2-tetralone (12f). Derived from 5,6-dimethoxy-2-tetralone and 2-nitro-4,5-dimethoxybenzaldehyde; melting point 70-72 ^o C; IR (nujol): 1715, 1550; ¹ H NMR: δ 2.59 (2H, t), 3.06 (2H, t), 3.78 (3H, s), 3.86 (3H, s), 3.88 (3H , s.), 3.92 (3H, s.), 6.47 (1H, s.), 6.77 (1H, d, J = 8.2), 7.41 (1H, d, J = 8.2), 7.67 (1H, s.); ¹³ C NMR: δ 19.7, 32.0, 56.3, 56.7, 56.8, 56.85, 108.1, 121.9, 125.6, 126.1, 128.0, 129 2, 132.1, 132.9, 133.7, 140.3, 141.4; 149.3, 152.9, 153.5, 200.9; Anal (C ₂₁ H ₂₁ NO ₇ ) C, H, N.

1- (2'-Nitro-4 ', 5'-dimethoxybenzylidene-6-chloro-2-tetralone (12j). Derived from 6-chloro-2-tetralone and 2-nitro-4,5-dimethoxybenzaldehyde; melting point 56 -58 ^° C; IR (nujol): 2922, 1730, 1100; ¹ H NMR: δ 2.68 (2H, t), 3.05 (2H, t), 3.62 (3H, s) 3.98 (3H, s), 6.48 (1H, s), 6.82 (1H, d, J = 8.4), 6.90-6.96 (1H, dd, J = 8.4, 2.1), 7.26 (1H, d, J = 2.1), 7.74 (1H, s.), 8.01 (1H, s.); ¹³ C NMR : δ 28.2, 37.4, 56.8, 56.9, 108.3, 112.2, 127.0, 127.2, 128.6, 130.9, 131.1, 133.3, 134.2, 134.5, 140.5, 141.5, 149.6; 153.7.

1- (2'-Nitro-4 ', 5'-dimethoxybenzylidene) -7-nitro-2-tetralone (Figure 3). Obtained from 7-nitro-2-tetralone and 2-nitro-4,5-dimethoxybenzaldehyde; melting point 125 ^o C;
IR (nujol): 1724, 1540; 1545; ¹ H NMR: δ 2.69 (2H, t), 3.16 (2H, t), 3.59 (3H, s), 4.01 (3H, s), 6.45 (1H , s.), 7.41 (1H, d, J = 8.1), 7.68 (1H, d, J = 2.2), 7.72 (1H, s.), 7.94 -7.99 (1H, dd., J = 8.4, 2.2), 8.08 (1H, s.); ¹³ C NMR: δ 28.4, 36.9, 56.9, 57.0, 108.7, 111.6, 123.2, 124.2, 126.1, 129.7, 132.5, 133 9, 135.8, 141.4, 145.8, 146.8, 150.1; 154.1, 198.4.

 EXAMPLE III - General procedure for the synthesis of derivatives of 5,6-dihydrobenz [a] acridine (figure 2).

 The corresponding derivative of 1- (2'-nitrobenzylidene) -2-tetralone (0.3 mmol) was dissolved in 10 ml of glacial acetic acid and heated in a flask under reflux with zinc dust (1.64 mmol) in a nitrogen atmosphere for 1- 4 hours. The reaction mixture was allowed to cool to room temperature and then the whole mixture was carefully passed through a silica gel (100 g) column and was chromatographed first with 500 ml of ethyl ether to remove acetic acid, followed by elution with hexane / ethyl acetate. The polarity of the mobile phase was reduced, if necessary, by mixing in suitable proportions of hexanes. The corresponding fractions were merged and concentrated in vacuo, giving 83-95% of the corresponding 5,6-dehydrobenz [a] acridines.

2,3,9,10-Tetramethoxy-5,6-dihydrobenz [a] acridine (13a). Obtained from 1- (2'-nitro-4 ', 5'-dimethoxybenzylidene) -6,7-dimethoxy-2-tetralone; melting point 182-183 ^o C; IR (nujol): 3210, 1615; ¹ H NMR: δ 2.99 (2H, t), 3.23 (2H, t), 3.94 (3H, s), 4.00 (3H, s), 4.02 (3H , s.), 4.04 (3H, s.), 6.79 (1H, s.), 7.10 (1H, s.), 7.31 (1H, s.), 7.54 (1H , s.), 8.17 (1H, s.); ¹³ C NMR: δ 28.8, 32.3, 56.5, 56.7, 105.7, 107.2, 107.5, 111.8, 123.9, 125.8, 127.1, 128 , 0, 130.5, 143.1, 148.8, 149.6, 152.8, 156.7; 176.7; HRMS calculated for C ₂₁ H ₂₁ NO ₄ : 351.1471; found 351.1475 /
2,3-Dimethoxy-9,10-methylenedioxy-5,6-dihydrobenz [a] acridine (13b). Derived from 1- (2'-nitro-4 ', 5'-methylenedioxybenzylidene) -6,7-dimethoxy-2-tetralone; melting point 218-219 ^o C; IR (nujol): 2780, 1630; ¹ H NMR: δ 2.97 (2H, t), 3.17 (2H, t), 3.93 (3H, s), 4.00 (3H, s), 6.07 (2H , s.), 6.79 (1H, s.), 7.07 (1H, s.), 7.29 (1H, s.), 7.32 (1H, s.), 8.07 (1H , from.); ¹³ C NMR: δ 29.0, 33.1, 56.5, 56.7, 102.1, 103.3, 105.7, 107.6, 111.8, 125.2, 125.9, 127 , 0, 128.0, 130.6, 145.0, 147.9, 148.8, 149.6; 150.8; 156.9; HRMS calculated for C ₂₀ H ₁₇ NO ₄ : 335.1158; Found: 335.1162.

9,10-Dimethoxy-5,6-dihydrobenz [a] acridine (13c). Derived from 1- (2'-nitro-4 ', 5'-dimethoxybenzylidene) -2-tetralone; melting point 95-96 ^o C; IR (nujol): 1633, 1516; ¹ H NMR: δ 3.06 (2H, t), 3.24 (2H, t), 4.02 (3H, s), 4.03 (3H, s), 7.10 (1H , s.), 7.28-7.37 (3H, m.), 7.50 (1H, s.), 7.82 (1H, d, J = 7.0), 8.29 (1H , from.); ¹³ C NMR: δ 29.2, 32.3, 56.5, 56.7, 105.9, 107.4, 124.0, 124.3, 127.3, 127.7, 128.5, 128 9, 129.1, 133.8, 137.6, 144.2, 150.5, 153.1; HRMS calculated for C ₁₉ H ₁₇ NO ₂ : 291.1259; Found: 291.1250.

2,3-Dimethoxy-5,6-dihydrobenz [a] acridine (13d). Derived from 1- (2'-nitrobenzylidene) -6,7-dimethoxy-2-tetralone; melting point 55-56 ^o C; IR (nujol): 2815, 1615; ¹ H NMR: δ 2.96 (2H, t), 3.23 (2H, t), 3.90 (3H, s), 3.98 (3H, s), 6.75 (1H , p.), 7.30 (1H, s.), 7.44 (1H, t.), 7.60 (1H, t.), 7.80 (1H, d, J = 10.2) 8.0 (1H, d, J = 10.2); 8.19 (1H, s.); ¹³ C NMR: δ 27.3, 28.9, 56.5, 56.6, 106.2, 110.7, 125.2, 125.5, 127.6, 127.8, 131.2, 132 4, 133.7, 133.9, 134.2, 136.3, 151.3, 153.6, 157.8; HRMS calculated for C ₁₉ H ₁₇ NO ₂ : 291.1259; Found: 291.1246.

5,6-dihydro-9,10-dimethoxy-3,4-methylenedioxybenz [a] acridine (13e). Obtained from 1- (2'-nitro-4 ', 5'-dimethoxybenzylidine) -5,6-methylenedioxy-2-tetralone; melting point 220-222 ^o C; IR (nujol): 1715, 1532; ¹ H NMR: δ 3.02 (2H, t), 3.19 (2H, t), 4.02 (3H, s), 4.03 (3H, s), 6.03 (2H , s.), 6.83 (1H, d, J = 8.1), 7.07 (1H, s.), 7.34-7.38 (2H, m.), 8.19 (1H , from.); ¹³ C NMR: δ 30.2, 32.3, 56.5, 56.6, 101.8 105.8 107.5 107.8 117.9 119.2 123.8, 126.9 128.3 128 7, 143.2 145.4 147.6 149.9 152.7, 156.3; Anal (C ₂₀ H ₁₇ NO ₄ ) C, H, N.

5,6-dihydro-3,4,9,10-tetramethoxybenz [a] acridine (13f). Obtained from 1- (2'-nitro-4 ', 5'-dimethoxybenzylidine) -5,6-dimethoxy-2-tetralone; melting point 195-196 ^o C; IR (nujol): 1730, 1515; ¹ H NMR: δ 2.82 (2H, t), 3.20 (2H, t), 3.86 (3H, s), 3.91 (3H, s), 4.03 (3H , s.), 4.04 (3H, s.), 6.93 (1H, d, J = 8.6), 7.10 (1H, s.), 7.52 (1H, s.) 7.56 (1H, d, J = 8.6); 8.27 (1H, s.); ¹³ C NMR: δ 21.8, 31.6, 56.4, 56.6, 56.8, 61.1, 105.8, 106.4, 106.5, 107.6, 111.4, 111 9, 120.4, 124.1, 127.1, 129.3, 131.6, 150.3, 150.4, 153.4, 156.3. Anal (C ₂₁ H ₂₁ NO ₄ ) C, H, N.

2-amino-9,10-dimethoxy-5,6-dihydrobenz [a] acridine (Figure 3, 20). Derived from 1- (2'-nitro-4 ', 5'-dimethoxybenzylidene) -7-nitro-2-tetralone; melting point 185 ^o C; IR (nujol): 3345, 2895, 1330; ¹ H NMR (CD ₃ DO): δ 2.96 (2H, t), 3.36 (2H, t), 3.98 (3H, s), 4.02 (3H, s), 7.24 (1H, d., J = 10.0), 7.32-7.38 (2H, m.), 7.88 (1H, s.), 8.17 (2H, s.); ¹³ C NMR: (CD ₃ DO): δ 24.5, 27.7, 57.0, 57.1, 99.4, 107.9, 117.1, 121.9, 123.2, 125.9 128.9, 130.1, 133.2; HRMS calculated for C ₁₉ H ₁₈ N ₂ O ₂ : 306.1369; found 306.1369.

3-Chloro-9,10-dimethoxy-5,6-dihydrobenz [a] acridine (13j). Derived from 1- (2'-nitro-4 ', 5'-dimethoxybenzylidene) -6-chloro-2-tetralone; melting point 197 ^o C; IR (nujol): 2895, 1105; ¹ H NMR: δ 2.96 (2H, t), 3.12 (2H, t), 3.97 (3H, s), 3.98 (3H, 2 s), 7.00 ( 1H, s.), 7.20-7.26 (2H, m.), 7.32 (1H, s.), 7.64 (1H, d, J = 8.1), 8.11 ( 1H, s.); ¹³ C NMR: δ 29.1, 32.6, 56.5, 56.6, 105.8, 107.8, 123.6, 125.6, 125.8, 127.7, 128.6, 128 8, 132.3, 133.9, 139.3, 144.4, 150.0, 153.0 156.6; HRMS calcd. C ₁₉ H ₁₆ CINO ₂ : 325.0869; Found: 325.0887.

 EXAMPLE IV - General procedure for the synthesis of benz [a] acridines and benz [c] acridines from their 5,6-dihydro derivatives (Figure 2).

 The corresponding derivatives of 5,6-dihydrobenz [a] acridine or 5,6-dihydrobenz [s] acridine (0.22 mmol) were heated under reflux in 15 ml of decalin with 76 mg of 10% palladium on charcoal under nitrogen in within 2-9 hours. Then the reaction mixture was quickly, while still hot, filtered with suction through a celite pad using a sintered glass funnel. The filter layer was thoroughly washed three times with 20 ml portions of boiling chloroform, and then with two 20 ml portions of boiling ethyl acetate. The combined filtrate was then concentrated in vacuo and dried in vacuo to give the corresponding benz [a] acridine derivatives.

2,3,9,10-Tetramethoxy-7-methylbenz [c] acridine (Figure 1, 7). Obtained from compound 6; melting point> 250 ^o C; IR (nujol): 3520, 1633, 1610; ¹ H NMR: δ 2.87 (3H, s), 4.03 (3H, s), 4.04 (3H, s), 4.13 (3H, s), 4.23 (3H , s.), 7.17 (1H, s.), 7.20 (1H, s.), 7.52 (1H, d, J = 9.2), 7.59 (1H, s.) 7.80 (1H, d, T = 9.2); 8.87 (1H, s.); ¹³ C NMR: δ 14.4, 56.4, 56.7, 101.7, 106.0, 108.2, 108.3 120.8, 122.1, 122.4, 125.5, 125, 8, 126.9, 128.6, 135.7, 139.0, 145.2, 149.8, 150.9, 153.3; HRMS calculated for C ₂₂ H ₂₁ NO ₄ : 363.1470; Found: 363.1472.

2,3,9,10-Tetramethoxybenz [a] acridine (14a). Obtained from compound 13a; melting point 247-249 ^o C; IR (nujol): 2810, 1630; ¹ H NMR: δ 3.99 (3H, s), 4.01 (3H, s), 4.03 (3H, s), 4.08 (3H, s), 7.08 (1H , s.), 7.12 (1H, s.), 7.41 (1H, s.), 7.74 (1H, d, J = 9.3), 7.81 (2H, m.) 8.82 (1H, s.); ¹³ C NMR: δ 56.3, 56.4, 56.5, 56.6, 103.9, 104.8, 106.8, 109.2, 122.8, 123.0, 124.5, 126 2, 126.4, 127.7, 130.7, 145.7, 147.2, 149.8, 149.9, 150.3, 153.9; HRMS calculated for C ₂₁ H ₁₉ NO ₄ : 349.1314; Found: 349.1314.

 2,3-Dimethoxy-9,10-methylenedioxybenz [a] acridine (14b).

Obtained from compound 13b; melting point 245-246 ^o C; IR (nujol): 2790, 1630; ¹ H NMR: δ 4.06 (3H, s), 4.16 (3H, s), 6.15 (2H, s), 7.25 (2H, s), 7.48 (1H , s.), 7.84 (1H, d, J = 8.2), 7.99 (1H, s.), 8.99 (1H, s.); ¹³ C NMR: δ 56.5, 56.6, 102.3, 102.4, 104.1, 104.9, 109.4, 112.8, 122.9, 124.4, 126.5, 126 7, 128.5, 130.9, 135.7, 147.0, 147.4 148.4, 150.1; 152.0; HRMS calculated for C ₂₀ H ₁₅ NO ₄ : 333,1002; found 333.1004.

9,10-Dimethoxybenz [a] acridine (14c). Obtained from compound 13c; melting point 181-182 ^o C, IR (nujol): 2883, 1621; ¹ H NMR: δ 4.09 (6H, s.), 7.26 (1H, s.), 7.54 (1H, s.), 7.60-7.71 (2H, m.), 7 89-7.96 (3H, m), 8.69 (1H, d, J = 8.1), 9.23 (1H, s); ¹³ C NMR: δ 56.6, 56.7 105.1, 107.1, 122.9, 123.3, 123.4, 125.5, 127.6, 128.5, 128.7, 129, 3, 130.4, 131.5, 131.6, 135.7, 146.4, 148.0, 150.6, 154.3. HRMS calculated for C ₁₉ H ₁₇ NO ₂ : 289.1104; Found: 289.1104.

2,3-Dimethoxybenz [a] acridine (14d). Obtained from compound 13d; melting point 190-192 ^o C, IR (nujol): 2881, 1632; ¹ H NMR: δ 4.02 (3H, s), 4.13 (3H, s), 7.18 (1H, s), 7.51-7.59 (1H, m), 7 , 72-7.81 (1H, m.), 7.83 (1H, s.), 7.89 (1H, s.), 7.93-8.22 (2H, m.), 8.23 (1H, d, J = 8.5); 9.13 (1H, s.); ¹³ C NMR: δ 56.5, 56.6, 104.4, 109.5, 124.2, 124.5, 126.3, 126.4, 126.8, 126.9, 128.5, 129 4, 130.0, 130.1, 130.2, 132.3, 148.1, 149.2, 150.1, 150.2; HRMS calculated for C ₁₉ H ₁₅ NO ₂ : 289.1104; found 289.1099.

3-Chloro-9,10-dimethoxybenz [a] acridine (14j). Obtained from compound 13j; melting point 241-243 ^o C; IR (nujol): 2893, 1108; ¹ H NMR: δ 4.04 (3H, s), 4.06 (3H, s), 7.09 (1H, s), 7.43 (1H, s), 7.51-7 57 (1H, doublet of doublets, J = 8.8, 2.2), 7.68 (1H, doublet, J = 9.1), 7.75 (1H, doublet, J = 2.2) 7.90 (1H, d, J = 9.1), 8.42 (1H, d, J = 8.8), 8.92 (1H, s); ¹³ C NMR: δ 56.6, 56.7, 104.9, 106.9, 122.7, 123.3, 124.3, 127.8, 128.2, 128.3, 128.6, 129 7, 130.2, 132.5, 133.2, 146.4, 147.4, 150.7, 154.4; HRMS calculated for C ₁₉ H ₁₄ CINO ₂ : 323.0713, found 323.0713.

EXAMPLE V - General Procedure for the N-methylation of benzo [a] acridines and benzo [c] acridines
Dimethyl sulfate (4 ml) was added to 0.27 mmol of the corresponding benzo [a] acridine or benzo [s] acridine, and this mixture was heated in a nitrogen atmosphere in an oil bath at 150 ^° C. for 20 minutes to 5 hours. Anhydrous ethyl ether (10 ml) was added to the reaction mixture with vigorous stirring, after which the mixture was cooled to room temperature. The quaternary salt that precipitated was filtered off with suction, washed three times with 10 ml portions of ethyl ether and dried. The quaternary salts crystallized from boiling methanol in 90% yield.

2,3,9,10-Tetramethoxy-7,12-dimethyl-5,6-dihydrobenz [c] acridinium methosulfate (Figure 1, 8). Obtained from compound 6, melting point> 250 ^o C; IR (nujol): 3510, 1645, 1613; ¹ H NMR (CD ₃ OD): δ 2.90 (3H, s), 2.96 (2H, t), 3.08 (2H, t), 3.93 (3H, s), 4.00 (3H, s.), 4.10 (3H, s.), 4.18 (3H, s.), 4.62 (3H, s.), 7.17 (1H, s.), 7.42 (1H, s), 7.61 (1H, s), 7.63 (1H, s), ¹³ C NMR: δ 16.6, 27.2, 29.0, 46.2 , 57.0, 57.2, 57.3, 57.4, 100.7, 105.5, 112.5, 115.2, 121.2, 125.1, 133.4 138.5, 139, 7 149.7 150.5, 152.7 152.9 154.8, 157.4; HRMS calculated for C ₂₃ H ₂₆ NO ₄ +: 380.1858; found 308.1856.

2,3,9,10-Tetramethoxy-7,12-dimethylbenz [s] acridinium methosulfate (Figure 1, 9). Obtained from compound 7, melting point> 240 ^o C; IR (nujol): 3495, 1640, 1615; ¹ H NMR (DMSO-d ₆ ): δ 2.53 (3H, s.), 3.39 (3H, s.), 3.97 (3H, s.), 4.03 (3H, s.) 4.16 (3H, s), 4.17 (3H, s), 7.69 (1H, s) 7.75 (1H, s), 7.91 (1H, s), 7.99 (1H, d, J = 9.5); 8.24 (1H, d, J = 9.5); ¹³ C NMR: δ 15.5, 55.4, 56.4, 56.5, 56.6, 56.7, 102.1, 106.3, 110.3, 111.2, 125.8, 123 2, 122.5, 128.8, 129.0, 130.9, 133.3, 139.0, 141.1, 147.6, 152.1, 153.8, 155.3; HRMS calculated for C ₂₃ H ₂₄ NO ₄ +: 378.1698; Found: 378.1695.

2,3,9,10-Tetramethoxy-7-methyl-5,6-dihydrobenz [a] acridinium methosulfate (15a). Obtained from compound 13a; melting point> 250 ^o C; IR (nujol): 3490, 1620; ¹ H NMR (DMCO-d ₆ ): δ 3.06 (2H, t), 3.37 (5H, t), 3.85 (3H, s), 3.93 (3H, s) 4.02 (3H, s), 4.05 (3H, s), 7.04 (1H, s), 7.45 (1H, s), 7.62 (1H, s) 7.63 (1H, s.); 9.29 (1H, s.); ¹³ C NMR: δ 25.9, 27.8, 53.1, 56.0, 56.1, 56.7, 56.8, 99.6, 106.6, 106.7, 107.9, 112 2, 112.3, 122.0, 124.4, 127.3, 129.1, 148.8, 150.3, 151.1, 153.0, 155.3; HRMS calculated for C ₂₂ H ₂₄ NO ₄ +: 366.1706; Found: 366.1706.

2,3,9,10-Tetramethoxy-7-methylbenz [a] acridinium methosulfate (16a). Obtained from compound 14a, melting point> 250 ^° C., IR (nujol): 2820, 1620; ¹ H NMR (DMSO-d ₆ ): δ 3.39 (3H, s.), 3.96 (3H, s.), 3.97 (3H, s.), 4.03 (3H, s.) , 4.07 (3H, s.), 7.59 (1H, s.), 7.67 (1H, s.), 7.85 (1H, d, J = 9.2), 8.25 (1H, s.), 8.31 (1H, d, J = 9.2), 8.75 (1H, s.), 10.18 (1H, s.); ¹³ C NMR: δ 54.4, 56.8, 56.9, 57.5, 57.9, 105.7, 106.7, 107.9, 110.4, 123.2, 125.3, 125 4, 127.8, 127.9, 128.3, 131.4, 146.8, 149.3, 152.0, 158.5, 159.9; HRMS calculated for C ₂₂ H ₂₂ NO ₄ +: 364.1549; Found: 364.1542.

 EXAMPLE VI - General procedure for the synthesis of 2,3,9,10-tetrahydroxy-5,6-dihydrobenz [a] acridine (Figure 2, 13g) and 2,3,9,10-tetrahydroxybenz [a] acridine (Figure 2, 14g).

The corresponding derivatives of benz [a] acridine (0.195 mmol) were dissolved in 2 ml of CH ₂ Cl ₂ and the solution was cooled to -50 ^° C using a cooling bath with isopropanol and dry ice. 1.95 mmol of a solution of boron tribromide (1.0 M) in CH ₂ Cl ₂ in a nitrogen atmosphere was added. The reaction mixture was stirred at -50 ^o C for one hour, and then she was allowed to slowly warm to room temperature for 4 hours. Then the reaction mixture was cooled to -10 ^° C and quenched by the addition of 5 ml of a saturated solution of ammonium chloride. The resulting solution was evaporated to dryness, and the obtained residue was extracted three times with 20 ml portions of boiling acetone. The resulting yellow suspensions each time
filtered out. The insoluble precipitate was dissolved in 5 ml of boiling methanol and left overnight. Needle crystals of the corresponding tetrahydroxybenz [a] acridines were formed in 95% yield.

2,3,9,10-Tetrahydroxy-5,6-dihydrobenz [a] acridine (13g). Obtained from compound 13a; melting point> 220 ^o C; IR (nujol): 3361, 3164, 2719, 1620; ¹ H NMR (CD ₃ OD): δ 2.97 (2H, t), 3.35 (2H, t), 6.77 (1H, s), 7.45 (3H, m), 8.83 (1H, s.); ¹³ C NMR (CD ₃ OD): δ 27.4, 29.2, 102.9, 110.9, 112.5, 116.6, 122.9, 126.5, 128.5, 129.4, 134.8, 135.6, 146.6, 148.6, 151.1, 152.9, 156.0; HRMS calculated for C ₁₇ H ₁₃ NO ₄ : 295.0845; Found: 295.0842.

2,3,9,10-Tetrahydroxybenz [a] acridine (14g). Obtained from compound 14a; melting point> 270 ^o C; IR (KBr): 3361, 3164, 1620, 1516; ¹ H NMR (CD ₃ OD): δ 7.26 (1H, s), 7.37 (1H, s), 7.56 (1H, s), 7.61 (1H, d, J = 9.2), 8.05 (2H, m.), 9.61 (1H, s.); ¹³ C NMR (CD ₃ OD): δ 101.1, 108.7, 110.3, 114.3, 114.7, 122.9, 124.4, 124.8, 126.7, 137.6, 137.8, 138.3, 139.0, 149.4, 150.7, 150.8, 159.3; HRMS calculated for C ₁₇ H ₁₁ NO ₄ : 293.0688; Found: 293.0685.

 EXAMPLE VII - Synthesis of 7-nitro-2-tetralone from 7-nitro-1-tetralone (figure 3).

7-Nitro-1,2,3,4-tetrahydro-1-naphthalenol. To a suspension of 2.88 g (15 mmol) of 7-nitro-1-tetralone in 60 ml of absolute ethanol was added 0.58 g (15 mmol) of sodium borohydride. The reaction mixture was then stirred at room temperature for 2 hours. The resulting mixture was rotary evaporated to dryness, and the residue was suspended in 100 ml of water. 3N hydrochloric acid was added dropwise until the pH of the mixture was 7. The resulting suspension was then extracted with five 50 ml portions of ethyl ether and the combined ether layer was then washed once with water (100 ml). The ether layer was dried over anhydrous sodium sulfate, filtered and rotary evaporated to give an off-white residue, which was recrystallized from a mixture (1: 1) of absolute ethanol and water, giving 2.68 g (92%) of naphthalenol; melting point 112-113 ^o C; IR (KBr): 3300; ¹ H NMR: δ 1.73-2.26 (4H, m), 2.29 (1H, s), 2.78-2.91 (2H, s), 4.83 (1H, m) .), 7.24 (1H, d, J = 8.1), 8.00-8.04 (1H, dd, J = 8.1, 2.4), 8.35 (1H d, J = 2.4); ¹³ C NMR: δ 19.2, 29.9, 32.5, 68.3, 122.7, 124.1, 130.3, 140.9, 145.4.

7-nitro-3,4-dihydronaphthalene. A mixture of 2.89 g (14.9 mmol) of 1-naphthalenol, 3.5 g of Amberlist-15 cation exchange resin and 120 ml of benzene was heated under reflux in a nitrogen atmosphere for 2 hours. Then the reaction mixture was cooled at room temperature and dried using anhydrous sodium sulfate and filtered. The filtrate was then rotationally evaporated to dryness to give the product as an oil in 92% yield. The product was reasonably pure and was used in the next step without further purification; IR (KBr): 1545; ¹ H NMR: δ 2.25-2.36 (2H, m), 2.77-2.86 (2H, t), 6.08-6.17 (1H, m), 6.40 -6.45 (1H, m.), 7.14 (1H, d, J = 8.1), 7.72 (1H, d, J = 2.3), 7.83-7.89 (1H, dd, J = 8.1, 2.3); ¹³ C NMR: δ 23.0, 27.9, 120.6, 122.1, 126.7, 128.6, 131.9, 135.6, 143.5, 147.3.

1,2-Epoxy-7-nitro-1,2,3,4-tetrahydronaphthalene. To a solution of 0.5 g (2.85 mmol) of 7-nitro-3,4-dihydronaphthalene in 9 ml of chloroform was added 0.677 g of m-chloroperoxybenzoic acid in one portion. The resulting solution was heated in a flask under reflux for 45 minutes. The mixture was then cooled to 0 ^° C and the precipitated m-chlorobenzoic acid was removed by filtration. The chloroform layer was rotationally evaporated to give a pale yellow solid, which was chromatographed on silica gel (50 g) and eluted with dichloromethane. The appropriate fractions were combined and rotary evaporated to give 0.487 g (89.5%) of the epoxide; melting point 73-74 ^o C, IR (KBr): 3300; ¹ H NMR: δ 1.70-1.86 (1H, m), 2.42-2.52 (1H, m), 2.54-2.90 (2H, m), 3.75 -3.77 (1H, t.), 3.91-3.93 (1H, d, J = 4.2), 7.22-7.26 (1H, d, J = 8.4) 8.05-8.11 (1H, dd, J = 8.4, 2.4); 8.24 (1H, d, J = 2.4); ¹³ C NMR: δ 21.6, 25.1, 52.3, 55.2, 123.8, 124.8, 129.8, 134.9, 145.0.

7-Nitro-2-tetralone. 0.37 g (1.1 mmol) of anhydrous zinc iodide was added to a solution of 0.5 g (2.6 mmol) of the above epoxide in 5 ml of dry benzene. The mixture was stirred at room temperature under nitrogen in the dark. After filtering and removing the solvent under reduced pressure, the resulting yellow oil was taken up in 3 ml of absolute ethanol when the product crystallized. Recrystallization from the concentrated mother liquor gave a total yield of 0.415 g (83%); melting point 96-97 ^o C; IR (KBr): 1710, 1330, 1500; ¹ H NMR: δ 2.59-2.66 (2H, t), 3.15-3.21 (2H, t), 3.72 (2H, s), 7.38-7.43 (1H, d, J = 8.3), 7.98 (1H, d, J = 2.2), 8.02-8.03 (1H, dd, J = 8.3, 2.2).

 EXAMPLE VIII - Analyzes - Materials.

 Plasmid pET11a and E. coli strain BL21 (DE3) used for the expression of enzymes were purchased from Novagen. IPTG was purchased from Sigma. The ECL system used to analyze Western blotting of bacterial lysates was supplied by Amersham (UK). All restriction enzymes and Vent polymerase were obtained from New England Biolabs. The mammalian topoisomerase II was isolated from calf thymus according to a published procedure (Halligan et al., J. Biol. Chem. 260: 2475-2482 (1985)). Single-copy YCpGAL1 yeast plasmids expressing various topoisomerase I genes in the yeast strain JN2-134 was kindly provided by Dr. M. -A. Bjornsti (Thomas Jefferson University, Philadelphia, RA). All bacteria and yeast culture media were obtained from Difco (Detroit, MI), and cell culture media were purchased from Flexo-BRL (Gaithersburg, MD).

 EXAMPLE IX - Expression of topoisomerase I of E. coli.

To obtain large amounts of human topoisomerase I, cDNA (complementary DNA) of human topoisomerase I was cloned into pET-11a vector, in which cDNA transcription is controlled by the inducible T7 promoter (Studier et al., Methods in Enzymol., Vol. 185: 60- 89, San Diego: Academic Press (1990)). Briefly, a 3.4 kb DNA fragment containing the entire coding sequence of human topoisomerase I and approximately 1 kb of the untranslated region below the termination codon were isolated from plasmid YCpGAL1-hTOP1 (Bjornsti et al., Cancer Res. 49: 6318-6323 (1989)) by cutting at BamHI and EcoRI sites. The pET-11a vector was excised using the same restriction enzymes, dephosphorylated, and crosslinked with the insert in the corresponding reading frame below the vector cloning site. An angiogenic mixture was used to transform E. coli, the correct clone pET1B was isolated, and its identity was confirmed by restriction mapping. Since the translation start in pET is located upstream of the Ndel site, the expressed topoisomerase I has a 15-amino acid fusion at its N-terminus. Then pET1B was transformed into E. coli BL21 (DE3), and after induction with 0.4 mM IPTG for 1 hour, the bacterial lysate was analyzed using 10% SDS-PAGE. Expression was confirmed by western blotting using rabbit antibodies against human topoisomerase I. Isolation of expressed protein was performed using a simple procedure. Briefly, E. coli cells were lysed by repeated ultrasound strikes. The preparation of the extract under the influence of ultrasound was carried out in 1M NaCl and 6% polyethylene glycol (PEG) to remove nucleic acids. The PEG supernatant was chromatographed directly on a hydroxyapatite column. Expressed topoisomerase I of human DNA was eluted at the stage of 0.6 M potassium phosphate. The eluted enzyme was then dialyzed against 50% glycerol, 30 mM potassium phosphate (pH 7.0), 1 mM dithiothreit (DTT) and 0.1 mM EDTA and stored at -20 ^° C. The relaxation activity of the purified enzyme was specific activity is about 2 orders of magnitude lower than calf thymus topoisomerase I.

 EXAMPLE X - Expression of camptothecin-resistant (CPT-K5) topoisomerase I in E. coli.

Two complementary oligonucleotides containing the point mutation CAG (Asp533) -> CGG (Gly), responsible for the resistance phenotype in CPT-5, were synthesized, and using genetic engineering methods were included in the sequence encoding topoisomerase 1 using the PCR method (Current Protocols in Molecular Biology, Ausubel et al. (Eds.), Vol. 1, pp. 8, 5, 7. Boston: Wiley Interscience (1991)). The two nucleotides are: 5'-CTTCCTCGGGAAGGGCTCCATCAGATAC-3 '(primer XI) (sequence ID N: 1) and 5'-GTATCTGATGGAGCCCTTCCCGAGGAAG-3' (primer X2) (sequence ID number: 2), where the underlined code is the sequence. Each oligonucleotide was used in separate PCR reactions to amplify two DNA segments adjacent to the mutation site using oligonucleotides 5'-ACTGTGATCCTAGGG-3 '("A") (sequence ID: 3) and 5'-CTTCATCGACAAGCTTGCTCTGAG-3' ( “H”) (sequence identification number: 4) as related primer pairs for X1 and X2, respectively. “A” and “H” are complementary to the sequence of human topoisomerase I, around the unique restriction sites AvrII and HindIII. After the first round of PCR, two amplified products - X1-H and X2-A - were denatured and hybridized using their complementary sequence of 15 base pairs, due to overlapping oligonucleotides X1 and X2. This short fragment of sequencing the double-stranded DNA segment was then increased by Vent polymerase at 72 ^° C. for 2 minutes into the product AH having a total length of 748 base pairs. The two outer primers, “A” and “H”, were then used to amplify a full-length DNA fragment containing a mutated topoisomerase I. The cDNA of the amplified mutant topoisomerase I was then digested with AvrII and HindIII and cloned into pET1B by replacing the corresponding AvrII / fragment HindIII in the cDNA sequence of topoisomerase I. Plasmid pET1B-CPTK-5, which contained cDNA of mutant topoisomerase I CPT-K5, was transformed into E. coli BL21 (DE3) for expression, instead of wild-type human topoisomerase I cDNA. After induction by IPTG, the presence of the protein in the lysates was confirmed by Western blotting. The CPT-K5 topoisomerase I was then purified from the bacterial lysate as described for the wild-type enzyme.

 EXAMPLE XI - Analysis of the cleavage of topoisomerase I and topoisomerase II.

 Cleavage analyzes of recombinant topoisomerases I and calf thymus topoisomerases I and II were performed as described (Liu et al., J. Biol. Chem. 258: 15365-15370 (1983)). The DNA of the YEpG plasmid used for cleavage assays was obtained and labeled at its 3'-end using published techniques.

 EXAMPLE XII - Analysis of cytotoxicity of yeast.

 It has been established that yeast can survive when the function of topoisomerase I is erased, and that poisons by topoisomerase I kill only cells that have functional topoisomerase I (Bjornsti et al. Cancer Res. 49: 6318-6323 (1989)). Thus, a comparison of the relative growth sizes of each of the test strains in the presence of various drugs with the control variants in which the drug is absent shows: 1) does this drug have any cytotoxic effect on yeast, 2) is this cytotoxicity topoisomerase I- specific, 3) whether there is any differential specificity of this drug for yeast, compared with human topoisomerase I.

In vivo analysis of topoisomerase I-specific cytotoxicity was adapted based on the methodology of Knab et al. (Knab et al., J. Biol. Chem. 268: 22322-22330 (1993)). In this system, various topoisomerase I genes cloned into a single copy yeast plasmid vector, YCpGAL1 (Knab et al., J. Biol. Chem. 268: 22322-22330 (1993)), are expressed under the control of the GAL1 promoter in strain JN2-134 of yeast S cerevisiae (MATa, rad52 :: LEU2, trp1, ade2-1, his7, ura3-52, ise1, top1-1, leu2) (Bjornsti et al. Cancer Res. 49: 6318-6323 (1989)). The topoisomerases I that are inserted into the vector are, respectively, wild-type yeast topoisomerase I (YCpGAL-ScTOP1), non-functional yeast topoisomerase 1, in which the tyrosine-727 active site, as a result of mutation, turns into phenylalanine (YCpGAL 1-Sctop1 Kn7 Y7) al., J. Biol. Chem. 268: 22322-22330 (1993)), and wild-type human topoisomerase I (YCpGAL-hTOP1) (Bjornsti et al., Cancer Res. 49: 6318-6323 (1989)). For a qualitative analysis of the cytotoxicity and topoisomerase of the I-specificity of drugs, yeast cells containing a specific plasmid were serially diluted (5-fold) and grown in an excavated medium supplemented with uracil and 2% galactose. In addition, tablets intended for positive and negative control contained: A: Control - without medication; B: Camptothecin (CPT), 0.5 μM; C: Coraline, 1 μM; D: Methylenedioxy-dihydro-demethyl-coraline (MDD-coraline), 1 μM; and E: Nitidine, 1 μM. The plates were cultured for 3 days at 30 ^° C. to analyze the lethal effect of different compounds and the test drug on various topoisomerase I enzymes expressed in S. cerevisiae.

 EXAMPLE XIII - Analysis of cytotoxicity.

The inhibitory concentration of IC _{50 of the} tested drugs was determined using the tetrazolinium cytotoxicity assay method in MTT microtiter plates (MTA method). (Mosmann, T., J Immunol. Methods, 65: 55-63 (1983); Denizot et al., J. Immunol. Methods 89: 271-277 (1986). Human lymphoblast cells RPMI 8402 and their camptothecin-resistant cells CPT-K5 (Andoh et al., Proc. Natl. Acad. Sci. USA 84: 5565-5569 (1987)) was kindly provided by Dr. Toshivo Ando (Central Aichi Cancer Research Institute, Nagoya, Japan). Cellular line A2780 and camptothecin-resistant derivative CPT-2000 were generously donated by Dr. Jaulang Hwang (Institute of Molecular Biology. Academy of Sciences, Taiwan). Cells (2000 cells per well, seeded in 200 ml of growth medium) were grown in suspensions at 37 ^o C in the atmosphere Hereafter, 5% CO ₂ and was maintained by passaging regularly into RPMI medium supplemented with 10% heat inactivated bovine fetal serum, L-glutamine (2 mM), penicillin (100 U / ml) and streptomycin (0.1 mg / ml). for 4 days, they were constantly exposed to drug concentrations in the range from 100 μg / ml to 1.0 ng / ml in 10-fold dilutions and were analyzed at the end of the fourth day. Each concentration and control (without drugs) was repeated at least twice, with 6 wells in each repetition. The results were plotted and then the IC ₅₀ was measured. The drug-sensitive human epidermoid carcinoma cell line, KB 3-1 line, and its multiple drug resistance variant selected with vinblastine, cell line KB-VI (Akiyama et al. Genetics 11: 117-126 (1985)) were kindly provided by Dr. Michael Gottsmann (National Cancer Institute). They were grown as single-layer cultures at 37 ^° C in an atmosphere of 5% CO ₂ and maintained by regular passaging in Dulbecco's minimal basic medium, supplemented with 10% inactivated elevated temperature fetal bovine serum. KB-VI cells were maintained in the presence of 1 mg / ml vinblastine.

 Tables 1, 2, a list of sequences and formulations are given at the end of the description.

Claims (22)

1. The compound of formula II

in which R ₁ and R ₂ independently represent OH, NO ₂ , NH ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy or R ₁ and R ₂ together represent —OCH ₂ O— ; R ₃ represents H;
R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy; or R ₅ and R ₆ together represent —OCH ₂ O—;
R ₇ represents H or (C ₁ -C ₈ ) alkyl;
or R ₁ , R ₂ , R ₃ , R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy;
R ₁ and R ₂ together represent —OCH ₂ O—; R ₂ and R ₃ together represent —OCH ₂ O—;
R ₅ and R ₆ together represent —OCH ₂ O—;
R ₇ represents H or (C ₁ -C ₈ ) alkyl,
with the proviso that one of R ₁ and R ₂ is (C ₁ -C ₈ ) alkoxy, or R ₁ and R ₂ together are —OCH ₂ O—;
or R ₁ , R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy;
R ₂ and R ₃ together represent —OCH ₂ O—;
R ₇ represents H or (C ₁ -C ₈ ) alkyl,
or a pharmaceutically acceptable salt thereof. 2. The compound of the formula

in which R ₁ and R ₂ independently represent NO ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy or R ₁ and R ₂ together represent —OCH ₂ O—;
R ₃ represents H;
R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy; or R ₅ and R ₆ together represent —OCH ₂ O—;
R ₇ represents H or (C ₁ -C ₈ ) alkyl;
or R ₁ , R ₂ , R ₃ , R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NHCO- (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy; R ₁ and R ₂ together represent —OCH ₂ O—;
R ₂ and R ₃ together represent —OCH ₂ O—;
R ₅ and R ₆ together represent —OCH ₂ O—;
R ₇ represents H or (C ₁ -C ₈ ) alkyl,
with the proviso that one of R ₁ and R ₂ is (C ₁ -C ₈ ) alkoxy, or R ₁ and R ₂ together are —OCH ₂ O—;
or R ₁ , R ₅ and R ₆ independently represent H, OH, NO ₂ , NH ₂ , halogen, NHCO (C ₁ -C ₈ ) alkyl or (C ₁ -C ₈ ) alkoxy;
R ₂ and R ₃ together represent —OCH ₂ O—;
R ₇ represents H or (C ₁ -C ₈ ) alkyl,
or a pharmaceutically acceptable salt thereof. 3. The compound according to claim 1 or 2, in which one or both R ₁ and R ₂ represent (C ₁ -C ₈ ) alkoxy. 4. The compound of claim 1 or 2, wherein both of R ₁ and R ₂ are (C ₁ -C ₈ ) alkoxy. 5. The compound according to claim 1 or 2, in which one or both of R ₁ and R ₂ represent methoxy. 6. The compound according to claim 1 or 2, in which R ₁ and R ₂ both represent methoxy. 7. The compound of claim 1 or 2, wherein R ₁ and R ₂ together represent —OCH ₂ O—. 8. The compound of claim 1 or 2, wherein R ₂ and R ₃ together represent —OCH ₂ O—. 9. The compound of claim 1 or 2, wherein R ₅ and R ₆ together represent —OCH ₂ O—. 10. The compound according to claim 1 or 2, in which R ₅ and R ₆ each independently represents OH or (C ₁ -C ₈ ) alkoxy or R ₅ and R ₆ together represent —OCH ₂ O—. 11. The compound of claim 1 or 2, wherein R ₅ and R ₆ each independently represents OH or (C ₁ -C ₈ ) alkoxy. 12. The compound according to claim 1 or 2, in which R ₅ and R ₆ each represents methoxy. 13. The compound according to claim 1 or 2, in which R ₇ represents hydrogen, methyl or ethyl. 14. Connection
2,3,9,10-tetramethoxy-5,6-dihydrobenz [a] acridine,
2,3-dimethoxy-9,10-methylenedioxy-5,6-dihydrobenz [a] acridine,
9,10-dimethoxy-5,6-dihydrobenz [a] acridine,
2,3-dimethoxy-5,6-dihydrobenz [a] acridine,
5,6-dihydro-9,10-dimethoxy-3,4-methylenedioxybenz [a] acridine,
5,6-dihydro-3,4,9,10-tetramethoxybenz [a] acridine,
2-amino-9,10-dimethoxy-5,6-dihydrobenz [a] acridine,
3-chloro-9,10-dimethoxy-5,6-dihydrobenz [a] acridine,
2,3,9,10-tetramethoxybenz [a] acridine,
2,3-dimethoxy-9,10-methylenedioxybenz [a] acridine,
9,10-dimethoxybenz [a] acridine,
2,3-dimethoxybenz [a] acridine,
3-chloro-9,10-dimethoxybenz [a] acridine,
2,3,9,10-tetramethoxy-7-methylbenz [a] acridinium methosulfate,
2,3,9,10-tetramethoxy-7-methyl-5,6-dihydrobenz [a] acridinium methosulfate,
2,3,9,10-tetrahydroxy-5,6-dihydrobenz [a] acridine or
2,3,9,10-tetrahydroxybenz [a] acridine
or a pharmaceutically acceptable salt thereof.  15. The compound according to claim 1, which is 5,6-dihydro-9,10-dimethoxy-3,4-methylenedioxybenz [a] acridine or a pharmaceutically acceptable salt thereof.  16. A pharmaceutical composition capable of inhibiting the growth of cancer cells, comprising a compound according to any one of claims 1 to 15, in combination with a pharmaceutically acceptable carrier.  17. A therapeutic method for inhibiting the growth of cancer cells, comprising administering to a mammal affected by cancer a certain amount of a compound according to any one of claims 1 to 15.  18. The method according to 17, in which the mammal is a human.  19. The method according to 17, in which the cancer is leukemia or melanoma.  20. The method according to 17, in which the cancer is a solid tumor.  21. The method according to claim 20, in which the tumor is a tumor of the breast, lung, colon or ovary.  22. The method according to 17, in which the compound is administered in combination with a pharmaceutically acceptable carrier.

Images