DK143849B - METHOD OF ANALOGUE FOR PREPARATION OF 5 (6) -SUBSTITUTED 1-THIAZOLINYL-2-AMINOBENZIMIDAZOLE COMPOUNDS - Google Patents

Description

(19) DENMARK (^)

il (12) PUBLICATION OF 143849 B

DIRECTORATE FOB PATENT AND TRADEMARKET SYSTEM

(21) Application No. 734/77 (51) IntCI.3 C 07 0 417 / OA

(22) Filing Day 18th Feb. 1977 (24) Running day Feb 18 1977 (41) Aim. available Aug. 19 1978 (44) Submitted 1 9 · Oct · 1 981 (86) International filing date - (86) International filing day - (85) Continuation day - (62) Master filing number - (30) Priority - (71) Applicant ELI LILLY AND COMPANY, Indianapolis, US.

(72) Inventor Charles Johnson Paget, US: James Wesley Chamberlin, US: James Howard Wikel, US.

(74) Associate Engineer Hofman-Bang & Boutard.

(54) Analogous procedure for the preparation of 5 (6) -substituted 1-thia = zoliny1-2-aminobenzimidazole compounds.

The incidence of viral disease in the upper part of the respiratory tract is enormous. It has been estimated that there are approximately 1,000,000,000 cases per year in the United States alone. Studies conducted in England [Tyreli and Bynoe, Lancet 1 »76 (1966) 3 have shown that 74% of people with a cold were infected with rhinoviruses. Since more than 80 strains of rhinoviruses have been identified so far, it is not possible to develop a practical rhinovirus vaccine. Here, chemotherapy has proved to be more suitable.

00 00 j- The ability of a chemical compound to suppress viruses in vitro is readily demonstrated by using a virus stain inhibition assay analogous to that *

ISLAND

2 U3869 is described by Siminoff, Applied Microbiology, 9 (1), 66 (1961).

Certain thiazolinylbenzimidazole compounds are described in the following patents: US Patent No. 3,749,717 discloses 1-thiazolinyl-2- (heterocyclic) benzimidazoles useful as worms and anti-inflammatory agents.

U.S. Patent No. 3,825,537 discloses 1-thiazolinyl-2-amino-benzimidazoles useful as worms and anti-inflammatory agents.

U.S. Patent No. 3,833,574 discloses a process for preparing 1-thiazolinylbenzimidazolin-2-ones useful as anti-inflammatory agents.

It is an object of the invention to provide novel benzimidazole compounds for use in pharmacological agents to suppress the growth of viruses, in particular rhinovirus, poliovirus, Coxsackie virus, echovirus, Mengovirus and influenza.

The invention thus relates to an analogous process for the preparation of novel pharmacologically useful 5 (6) -substituted 1-thiazolyl-2-aminobenzimidazole compounds of the general formula I set forth in the preamble of the invention and the process according to the invention is characterized by the characterizing part of the claim. .

The term "tautomer benzimidazole" refers to a 2-iminobenzimidazole which contains on both ring nitrogen atoms a hydrogen atom. The benzimidazole reactant, which is unsubstituted on one ring nitrogen atom and which contains a substituent group at the 5-position of the benzene moiety, has a corresponding tautomeric equilibrium with the substituent alternatively sitting at the 6-position. The isomeric mixture can be indicated by numbering the alternative positions as 5 (6).

The term alkyl of 1-7 carbon atoms refers to straight chain or branched chain aliphatic alkyl groups of 1-7 carbon atoms comprising methyl, ethyl, propyl, isopropyl, hutyl, isobutyl, sec.-butyl, pentyl, isopentyl, hexyl, isohexyl, heptyl , isoheptyl, 2,4-dimethyl-3-pentyl, tert-butyl, and neopentyl.

An alkyl magnesium halide having 1-7 carbon atoms is a suitable Grigard reagent. Alkyllithium with 1-7 carbon atoms also leads to a product similar to a Grignard reagent. Preferred solvents for use in the alkylation process are inert organic solvents such as tetrahydrofuran, aromatic solvents such as benzene or toluene, and ethers such as diethyl ether. Temperatures of approx. 25 ° C to the boiling point of the solvent.

The starting materials of formula II are prepared as described in Danish Patent Application No. 3861/76.

The thiazolinylbenzimidazole compounds are isolated by known methods such as filtration and concentration of the filtrate to produce crystallization. Alternatively, the reaction mixture can be evaporated to dryness and the residue treated with a suitable solvent, such as acetone or methanol, to separate and remove insoluble matter. The solution containing the product is concentrated to crystallize the product or evaporated to obtain another residue which is recrystallized from e.g. methanol. The benzimidazole compound is recovered by filtration after centrifugation.

The 5 (6) isomers can be separated by fractional crystallization or by column chromatography. Usually the 6 isomer crystallizes first from a solution of the mixture.

The following examples further illustrate the preparation of the subject compounds of formula I. The term m / e used in characterizing the compounds refers to the ratio of mass to charge of the ions present in the mass spectrum of the compound. In general, the value corresponds to the molecular weight of the main fractions.

EXAMPLE 1 4 g (12.4 mmol) of 1- (thiazolin-2-yl) -2-amino-6-benzoylbenzimidazole was added to 1000 ml of tetrahydrofuran under nitrogen at a temperature of -10 ° C. To the solution was added dropwise under nitrogen 50 ml (1.6M) of n-butyllithium in hexane. The temperature rose to -5 ° C. The temperature of the solution was kept at -5 to 10 ° C for 1 hour. The solution was heated to 25 ° C and kept at this temperature for 3 hours. The solution was poured into 1 liter of water, evaporated, washed with tetrahydrofuran and filtered to give 4.56 g of 1- (thiazolin-2-yl) -2-amino-6- (α-hydroxy-an-butylbenzyl) benzimidazole as a white substance, Imip. 206-209 ° C.

EXAMPLE 2

The procedure of Example 1 was repeated using 5 g (15.5 mmol) of 1- (thiazolin-2-yl) -2-amino-6-benzoylbenzimidazole, 500 ml of tetrahydrofuran and 50 ml (2.1M in diethyl ether) isopropylmagnet -sium bromide to give 1.24 g of 1- (thiazolin-2-yl) -2-amino-6- (α-hydroxy-α-isopropylbenzyl) benzimidazole, m.p. 212-215 ° C.

EXAMPLE 5

The procedure of Example 1 was repeated using 2.0 g (6.22 mmol) of 1- (thiazolin-2-yl) -2-amino-6-benzoyl-benzimidazole, 23 ml (1.25 M in benzene). ) ethyl lithium and 500 ml of tetrahydrofuran to give 2.5 g of 1- (thiazolin-2-yl) -2-amino-6- (α-hydroxy-α-ethylbenzyl) benzimidazole, m.p. 206-208 ° C m / e 352.

testing Methods

Cells from the kidney of African monkeys (BSC-1) or Hela cells (5-3) were cultured in 25 ml Falcon flasks at 37 ° C in medium 199 with 5% inactivated bovine serum (FBS), penicillin (150 units, 1 ml) and streptomycin (150 µg / ml). When confluent monolayers were formed, the growth medium above was removed and 0.3 ml of a suitable dilution of virus (echo, Mengo, Coxsackie, polio, or rhino virus) was added to each flask. After absorption for 1 hour at room temperature, the virus-infected cell layers were poured with a medium containing one part 1% ionagar # 2 and one part double strength medium 199 with FBS, penicillin and streptomycin containing the active compound in concentrations of 100, 50, 25, 12, 6, 3, 1.5 and 0.75 / µg per day. milliliter. The flask, which did not contain active compound, served as a control in the experiment. Stock solutions of thiazolinylbenzimidazole compounds of formula I were prepared in dimethyl sulphoxide at a concentration of 10 µg / ml. The flasks were incubated for 72 hours at 37 ° C for polio, Coxsackie, echo and Mengovirus, and 120 hours at 32 ° C for rhino virus. Influenza viruses of type Ann Arbor, Maryland B, Massachusetts B, Hong Kong A, Pr-8a, and Taylor C (types A, B) were incubated for 72 hours at 37 ° C using MDCK cells (Madin-Darby rabbit kidney cells) . Stains could be observed in areas where viruses were infected and reproduced in the cells. A solution of 10 formaldehyde and 2% sodium acetate was added to each flask to inactivate the virus and fix the cell layer to the flask surface. Virus stains, regardless of size, were counted after staining the surrounding cell areas with crystal violet. The spot number was compared to the control number for each active compound concentration. The activity of the subject compound was expressed as the percentage reduction in stain number or percent inhibition. Alternatively, the concentration of active compound may be indicated by the symbol I q, which indicates the concentration which inhibits the formation of the spots by 50%.

The test results are expressed in the form of poliovirus type I inhibition, as this virus is easy to grow and gives consistent test results. However, the effect of the present compounds of formula I is confirmed against other viral cultures such as Coxsackie (A9, A21, B5), echo virus (strains 1-4), Mengo rhinovirus (25 strains), Polio (type I, II, III ), and influenza viruses such as Ann Arbor, Maryland B, Massachusetts B, Hong Kong A; Pr-8Å and Taylor C (types A, B). Test results for the compounds of Examples 1-3 are set forth in Table I below and compared to Compound A (1- (thiazolin-2-yl) -2-amino-5-ethoxy-carbonylbenzimidazole), which is known from U.S. Pat. .

In the table, column 1 gives a reference to the examples described in column 2, isomer is listed in 5 (6) position, and columns 3-10 indicate the reduction of stains at various dilutions of the active compound. , more specifically, from 0.75 to 100 µg per day. milliliter.

Table I Polio-I stain reduction with 5 (6) -substituted 1-thiazolin-2-yl-2-aminobenzimidazole compounds.

Concentration (µg / ml) S_

Pre- Isomer h bin .T 100 50 25 12 6 3 1.5 0.75 ® Distribution 4 * 4 ---- --——. φ ex 3 6 toxic toxic slightly 86 43 19 0 0 c ______toxic______g; Ex. 1 6 Toxic Toxic Toxic To- 74 26 7 0 o __ ____xic________, 3 Ex. 2 6 Toxic Toxic To. 87 0 0 0 0 ______ toxic_______ A 5 100 97 74 44 0 0 0 0 5 Concentration of active compound in µg per ml. ml M The numbers 5 or 6 indicate the respective isomer

The present 1-thiazolinylbenzimidazole compounds were tested both as pure compounds and as isomeric mixtures. Both isomers inhibit viral growth, although the 6-isomer is generally more active than the 5-isomer.

The present compounds may be administered orally to warm-blooded mammals and humans at doses of 1 to 300 mg / kg body weight. The administration may be repeated if necessary. According to general practice, the antiviral compound can be administered every four to six hours.

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