Mercapto benzimidazoles

Benzenemethanethiol,a-(selenylmethylene)-metal complexes, 809 Benzeneselenic acid metal complexes, 807 Benzenetetrathiols metal complexes, 606 Benzenethiol, 2-amino-metal complexes, 799 Benzenethiol, o-hydroseleno-metal complexes, 809 Benzimidazole, 2-guanidinium-metal complexes, 283 Benzimidazole, 2-mercapto metal complexes, 802 Benzimidazole, 2-(2-pyridyl)-metal complexes, 93 Benzimidazoles metal complexes, 78, 85 P a, 11... 

Nitro-l-isothiocyanato-benzol wird reduktivzu2-Mercapto-benzimidazol-3-oxid cy-clisiert3 ... 

A useful and simple preparation of the thiazolo[3,2-tf]benzoimidazol-3(2//)-one 391 is the reaction of 2-mercapto-benzimidazole 390 with chloroacetyl chloride (Equation 177) <1996MI442>. 

Two approaches have been applied for the synthesis of imidazo[2,l + thia/,ole ring systems. Reaction of 2-mercapto-benzimidazole with perfluoro-2-methylpent-2-ene in the presence of triethylamine gave compound 419 (Equation 192), and cyclocondensation of 2-imidazolidinethione with the alkynyl(phenyl)iodonium salt 420 afforded product 421 (Equation 193) <2001RCB1446, 2003JCM715>. 

Abstract This presentation is a brief review on the resnlts of our work on iodine interaction with thioamides, selenoamides and amides. The thioamides, benzothia-zole-2-thione (BZT) (1), 6-n-propyl-2-thiouracil (PTU) (2), 5-chloro-2-mercap-tobenzothiazole (CMBZT) (3), N-methyl-benzothiazole-2-thione (NMBZT) (4), benzimidazole-2-thione (BZIM) (5), thiazolidine-2-thione (TZD) (6), 2-mercapto-pyridine (PYSH) (7), 2-mercapto-nicotinic acid (MNA) (8), 2-mercapto-benzoic acid (MBA) (9) and 2-mercapto-pyrimidine (PMT) (10) react with producing three type of complexes of formulae [(HL)IJ(l2) (HL= thioamide and n= 0, 1), [(HL) [I3 ] and [(HL-L)]+[l3 ]. The interaction of seleno-amides, derived from, 6-n-propyl-2-thiouracil (RSelJ) (R= Me- (11), Et- (12), n-Pr- (13) and i-Pr- (14)) with I, have also been studied and produced the complexes [(RSeU)IJ of spoke structure. These complexes are stable in non-polar solvents, but they decompose in polar solvents, producing dimeric diselenide compounds or undertake deselenation. 

Hydroxy-, Mercapto- oder Amino-benzimidazole besitzen weitere acide Protonen, die am Gleichgewicht tcilnchmcn z. B.33 ... 

Dithiokohlensaure-anilid-S-cstcr kondensieren mit o-Diamino-arenen in Gegcnwart von Quecksilberoxid als Schwefelfanger zu 2-Anilino-benzimidazolen ohne Quecksilberoxid wird 2-Mercapto-benzimidazol erhalten293 294. 

Tab. 14 2-Mercapto-benzimidazole durch Cyclisierung von o-Diamino-arenen mit Kohlen-...

Backerhefe oxidiert 2-Mercapto-benzimidazole zu Bis-[2-benzimidazolyl]-disulfanen380. Auch die Verwen clung von Benzolsulfonylchlorid als Oxidationsmittel ist moglich383. 

Tab. 25 2-Alkylthio- bzw. 2-Arylthio-benzimidazole durch Alkylierung bzw. Arylierung von 2-Mercapto-benzimidazolens a 372...

Mercapto-benzimidazol (und ahnliche ambidente Nukleophile) werden mit Kohlensaure-al-lylestern thermodynamisch kontrolliert am S-Atom angegriffen, wenn man das thiophile Palladium ) als Katalysator einsetzt. Mit 3-Ethoxycarbonyloxy-l-phenyl-propen II erhalt man 2-(3-Phenyl-allylthio)-benzimidazol (III 36%), mit 2 Aquivalenten an II l-(3-Phenyl-allyl)-2-(3-phenyl-allyIthio)-benzimidazol (IV 52%) neben einer geringen Menge l,3-Bis-[3-phenyl-allyl)-2-thiono-2,3-dihydro-benzimidazol (V 7%)378. 

Die Ambivalenz bzw. Tautomerie von 2-Mercapto-benzimidazol ist verantwortlich fur seine Fahigkeit, elektrophile Alkine, sowohl am S- als auch am N-Atom zu addieren. In protischen Losungsmitteln (Methanol368,369, 376 oder Acetonitril/Wasser368,376) ist der Angriflf am S-Atom bevorzugt z. B.369. 

Zweifache Addition an 2-Mercapto-benzimidazol zu l-(3-Oxo-3-pke.nyl-propenyl)-2-(3-oxo-3-phenyl-propenylthio) -benzimidazol (44% Schmp. 190-192°) wird mit 3-Oxo-3-phenyl-pro-pin in Acetonitril beobachtet577 ... 

Bei der Reduktion von 2-Sulfo-benzimidazolen I mit Ammonium-formiat entstehen neben 2-Mercapto-benzimidazolen II die desulfurierten Benzimidazole III. Die 2-Mercapto-benzimidazole II selbst werden unter diesen Bedingungen (Erhitzen in Substanz) nicht zum Benzimidazol III reduziert391 ... 

Mercapto-aryl)-benzimidazole cyclisieren bei der Oxidation mit Brom240 ... 

Mercapto-benzimidazol wird von Allyl-bromid in Gegenwart von Natriumhydrogencarbonat zunachst am S-Atom zu 2-Allylthio-benzimidazol (60%) alkyliert. Beim Erwarmen wandert der Allyl-Rest (Claisen-Umlagerung) vom S- zum N-Atom, und man erhiilt l-Allyl-2-mer-capto-benzimidazol (50% Schmp. 115—117°)372. 

Akasaki and Ohno206 recently found that S-phenacyl-2-mercapto-benzimidazole (197) on treatment with benzoyl chloride did not give the expected N-benzoyl derivative but the benzimidazothiazole 198 in quantitative yield. Exploration of the mechanism revealed a complicated sequence of acyl migrations, which, though not yet fully elucidated, may have important biochemical implications, particularly on the mode of action of biotin. 

The effect of amino, hydroxy or mercapto substituents is to increase hydrogen bonding properties. However, if stable hydrogen bonds are formed in the crystal, then this can decrease their solubility in water (63PMH(l)177), e.g. indazole and benzimidazole are less soluble than benzoxazole. 

Omeprazole was prepared [19] by reaction of 4-methoxy-o-phenyl-enediamine 1 with potassium ethyl xanthogenate 2 to give 5-methoxy-2-mercapto-lH-benzimidazole 3. Treatment of compound 3 with 3,5-dimethyl-4-methoxy-2-chloromethyl pyridine 4 in sodium hydroxide... 

Knoth et al. [48] studied the electrochemical behavior of omeprazole with the aid of the direct-current and differential-pulse polarography. Omeprazole was determined in Britton-Robinson buffers pH 7-9 up to a concentration of 10 5 M. The mechanism of the reduction process on the dropping mercury electrode is elucidated. With the consumption of two electrons and two protons, omeprazole will be reduced to 5-methoxy-2-[(3,5-dimethyl-4-methoxypyridin-2-yl)methylthio]-lH-benzimidazole which will be cleaved with the uptake of two further electrons and two protons into 4-methoxy-2,3,5-trimethyl pyridine and 2-mercapto-5-methoxybenz imidazole. 

Reaction of recently synthesized 1 -al kvnyl />-( trifluoromethyl )phenyl]( tetrafluoro-borato)-X3-bromanes with 2-mercapto- benzimidazole or benzothiazole in dichloro-methane at 0°C under argon resulted in a domino Michael addition-carbene rearrangement-cyclization reaction to produce directly tricyclic heterocycles in high yields (Scheme 67).103... 

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