Abstract: The small mol., isatin, is a well-known reversible inhibitor of the monoamine oxidase (MAO) enzymes with IC50 values of 12.3 and 4.86μM for MAO-A and MAO-B, resp. While the interaction of isatin with MAO-B has been characterized, only a few studies have explored structure-activity relationships (SARs) of MAO inhibition by isatin analogs. The current study therefore evaluated a series of 14 isatin analogs as in vitro inhibitors of human MAO-A and MAO-B. The results indicated good potency MAO inhibition for some isatin analogs with five compounds exhibiting IC50 < 1μM. 4-Chloroisatin (1b) and 5-bromoisatin (1f) were the most potent inhibitors with IC50 values of 0.812 and 0.125μM for MAO-A and MAO-B, resp. These compounds were also found to be competitive inhibitors of MAO-A and MAO-B with Ki values of 0.311 and 0.033μM, resp. Among the SARs, it was interesting to note that C5-substitution was particularly beneficial for MAO-B inhibition. MAO inhibitors are established drugs for the treatment of neuropsychiatric and neurodegenerative disorders, while potential new roles in prostate cancer and cardiovascular disease are being investigated.
* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With magnesium; In tetrahydrofuran; diethyl ether;
Preparation 9 5-Chloro-3-(2-chloro-4-fluorophenyl)-3-hydroxyindolin-2-one, Compound II.10 0.44 g of a 60% dispersion of sodium hydride in oil is added at -40 C. to a cooled suspension of 2 g of 5-chloroindolin-2,3-dione in 60 ml of tetrahydrofuran and the reaction mixture is stirred at 0 C. for 15 minutes. 0.45 g of magnesium and 4.23 g of <strong>[101335-11-9]2-chloro-4-fluoro-1-iodobenzene</strong> in 18 ml of diethyl ether are stirred at reflux for 3 hours. The solution thus obtained is slowly added at -60 C. to the reaction mixture. The reaction mixture is stirred for 30 minutes at 20 C. and a saturated aqueous ammonium chloride solution is added. Extraction is carried out with ethyl acetate, the organic phase is dried over anhydrous sodium sulphate and the solvents are evaporated under reduced pressure. The residue obtained is purified by chromatography on a column of silica gel, elution being carried out with dichloromethane and then with a 95/5 (v/v) dichloromethane/methanol mixture. The solid obtained is crystallized from n-pentane; M.p.=239 C. In the same way, 5-chloro-3-(2,5-dimethoxyphenyl)-3-hydroxyindolin-2-one, compound II,11;
(N,N'E,N,N'Z)-N,N′-(5-chloroindoline-2,3-diylidene)bis(5-nitrobenzo[d]thiazol-2-amine)[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
68%
With acetic acid; In methanol;Reflux;
A 10mmol solution of 5-nitro-2-aminobenzothiazole in 30 mlmethanolwas added drop wise to a 5 mmol solution of 5-chloroisatin dissolvedin 30 ml methanol. The reaction mixture was refluxed for 6 hin the presence of catalytic amount of glacial acetic acid (1-3 drops)which led to the isolation of microcrystalline solid product (Scheme 1).The productwas filtered,washed several timeswithmethanol and finallydried in vacuum over anhydrous calcium chloride.
5-chloro-6'-(4-fluorophenyl)-2',5'-diphenyl-1',2'-dihydrospiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,3'(7'H)-dione[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
90%
With acetic acid; In water; at 90℃; for 5h;Green chemistry;
General procedure: The mixture of isatin (1 mmol), 3-amino-1-phenyl-1H-pyrazol-5(4H)-one (1 mmol), 1,2-diarylethan-1-one, 2,3-dihydroinden-1-one (1 mmol) or 3,4-dihydronaphthalen-1(2H)-one (1 mmol), H2O (6 mL), HOAc (2 mL) was put in a reaction flask under 90 C about 5-7 h (monitored by TLC). After completion, the reaction mixture was cooled to room temperature and the products would be isolated out at same time. Then, compound 4 was recrystallized from DMF, however, the pure products of 6 and 8 were filtered from water, dried, without further recrystallization.
3-(2-amino-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)-5-chloro-3-hydroxyindolin-2-one[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
68%
In water; at 80℃; for 6h;
A solution of 200?mg (1.10?mmol) of 5-chloroisatin (1c), 153?mg (1.10?mmol) of <strong>[873-95-0]3-amino-5,5-dimethylcyclohex-2-enone</strong> (2b) was heated to 80 C in H2O for 6?h. After the TLC indicated the complete consumption of 5-chloroisatin (1c), the reaction mixture was extracted with ethyl acetate three times. The combined organic layer was dried over Na2SO4 and evaporated on rotatory evaporator to provide light yellow solid which was purified by silica gel column chromatography using hexane:ethyl acetate (2:8) as an eluent to provide 7 as white solid (239?mg).
68%
In water; at 80℃;Green chemistry;
General procedure: A mixture of isatin (1a) (0.3 gm, 2.0 mmol) and enaminone (2a) (0.333 gm,2.4 mmol) in 10 mL of water was heated in an oil bath at 80C for 9 hours. Initially,orange-colored reaction mixture appeared to be homogeneous but with the progress ofthe reaction, yellow color solid precipitated out. After the TLC indicated the completeconsumption of starting materials, the precipitated solid was filtered off. The solid wasthen dried under vacuum and purified by silica gel column chromatography by using EA: hexane (8:2) as an eluent to provide the desired product.
With 2-amino-2-hydroxymethyl-1,3-propanediol; In ethanol; at 20℃; for 5h;
General procedure: To a well-stirred solution of isatin and malononitrile(1 mmol each) in ethanol (95%, 4 mL) was added dimedone,4-hydroxycoumarin, 4-hydroxy-N-methylquinolin-2-one,or 2-methyl-pyrazol-2-one [generated in situ from ethylacetoacetate and hydrazine hydrate, 1 mmol each]. To thissolution was added THAM (30 mol %) and stirring wascontinued at ambient temperature. Upon completion of thereaction (TLC), water (5 mL) was added and stirring wascontinued for 10 min more. Resultant solid product wasfiltered, washed repeatedly with water, and dried. The dried solid was washed thrice with hexaneechloroformmixture (1:1, v/v) and dried again. Resultant product didnot require any further purification.
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