Thiazoles benzo

The usual order found with halogenonitrobenzenes is F > Cl Br I, the order of Cl and Br being variable, just as in heteroaromatic reactivity. The position of fluorine is of interest the available data indicate that it is usually the same as for nitrobenzene derivatives. Thus, in acid hydrolysis the order F > Cl for 2-halogeno-quinolines can be deduced beyond doubt since the fluoro derivative appears to react in the non-protonated form and the chloro derivative to resist hydrolytic attack even in the protonated form under appropriate conditions (Section II,D, l,d). Furthermore, in the benzo-thiazole ring, fluorine is displaced by the CHgO reagent at a rate 10 times that for chlorine. ... 

C23H30O7 133991-63-6) see Loteprednol etabonate (3p,16p,17a,18p,20a)-18-[[3-I4-t(ethoxycarbonyl)oxy]-3-methoxyphenyl)-l-oxo-2-propenyl]oxy]-ll,17-dimeth-oxyyohimban-16-carboxylic acid methyl ester (C3ftH42N20(o 49806-34-0) see Rescimetol AT-(l-ethoxycarbonyI-3-phenylpropyl)-L-alanine (C,, H 3N04) see Quinapril hydrochloride A7-[l(5)-ethoxycarbonyl-3-phenylpropyl]-L-alanine (C,gH2 N04 82717-962) see Imidapril Moexipril Quinapril hydrochloride Spirapril Trandolapril A -[l(5)-ethoxycarbonyl-3-phenylpropyl]-L-aIanine benzo-thiazol-2-yIthio ester... 

Hexamethyiene tetramine Mercapto benzo thiazole Ortfio-toiuidine Para-loluidine... 

Hexamethylene tetramine Mercapto benzo thiazole Ortho-toluidine Para-toluidine... 

In contrast, thiazoles and benzothiazoles are suitable recipients for the heteroaryl Heck reaction. Treatment of 2-chloro-3,6-diisobutylpyrazine (103) with thiazole led to regioselective addition at C(5), giving rise to adduct 104 [57]. A similar reaction between 2-chloro-3,6-diethylpyrazine (105) and benzo[ >]thiazole took place at C(2) exclusively to afford pyrazinylbenzothiazole 106 [57]. 

Replacement of the urethane carbonyl function by an aromatic ring leads to a benzo-thiazole that is described as an immune function modulator. In an analogous approach to that used above, anilinothiol (63-1) is condensed with the thiocarbamoyl chloride (63-2) again in the presence of a base. This leads directly to frentizole (63-3) [66]. 

Fio. 1. Bronsted plot for azoles reacting with methylating agents in quaternization reactions. Pyridine is the reference substrate. 1, 1-methylimidazole 2, 1-methylbenzimidazole 3, thiazole 4, 1-methylpyrazole 5, 2-methylindazole 6, benzo-thiazole 7, oxazole 8, 1-methylindazole 9, benzoxazole 10, 2,1-benzisothiazole 11, isothiazole 12, 2,1-benzisoxazole 13, isoxazole and 14, 1,2-benzisoxazole. 

The H NMR chemical shifts of 5- and 6-substituted benzoxazoles, benzo-thiazoles, and benzoselenazoles were measured [737],... 

H,8H-< Azeto[2, l-b]-l,3-benzothia-zine) 2a-Aryl-2-chIor-5,6-dimethoxy-1 -oxo-2,2a-dihydro-E14a/3, 537 (2-Ar-4H-l,3-benzo-thiazol + Cl - CH2 - CO - Cl)... 

Azetidin 3-Chlor-4-ethyl-2-oxo-l-(4,5,6,7-tetrahydro-l, 3-benzo-thiazol-2-yl-amino)- El6b. 520 (Hydrazon + Cl —CH2 —CO — Cl)... 

Cyclopent b -l,4-benzothiazine 9-Acetyl-12,3,9-tetrahydro- E9a, 475 (3-Ac-2,3-H2 — 1,3-benzo-thiazol-<2-spiro)-cyclopentan/ S02CI2)... 

Recent analyses of a Free-Wilsontype have included the in vitro inhibitory activity of a series of heterocyclic compounds against K. pneumonia (197). Other applications of the Free-Wilson approach have included studies on the antimycobacterial activity of 4-alkyl-thiobenzanilides, the antibacterial activity of fluoronapthyridines, and the benzodiazepine receptor-binding ability of some non-benzodi-apzepine compounds such as 3-X-imidazo-[l,2-6]pyridazines, 2-phenylimidazo[l,2-o ]pyri-dines,2-(alkoxycarbony)imidazo[2,l-p]benzo-thiazoles, and 2-arylquinolones(198-200). 

Hunig and co-workers have described violene systems where the benzo-thiazole or benzoxazole parts are separated by a polyene chain the consequence for the formation constants of the radical-cation (e.g., 216) of variation in n was studied. The consequences of aza substitution in the chain were also studied. In general, extension of the conjugation destabilizes the radical-cation relative to the upper and lower oxidation states. (See also Part I Section II,B,2.)... 

The acyl radicals thus produced acylate heteroaromatic bases. Thus benzo-thiazole is converted into 2-acetylbenzothiazole when acetaldehyde is used as the radical precursor. Aromatics such as N,N-dimethylaniline do not react, and hence this new type of free-radical acylation is opposite to the usual electrophilic aromatic acylation. 

Acetic formic anhydride is a versatile reagent in organic synthesis (review [3823]), for example, when it is stirred with an o-aminothiophenol. a 2-unsub-stituted benzothiazole is formed. Aminothiophenols, like their oxygen counterparts [2111], are cyclized by carboxylic acids or their esters, and also by dichloromethyleneammonium salts (review [2549]) to give good yields of benzo-thiazoles [2548]. The use of a dithioic ester is shown in Section 1.2 [2860]. 

R Reaktionsbedingungen. .. -4,5,6,7-tetrahy-dr o-l, 3-benzo-thiazol [%] Schmp. [JCJ Lite- ratur... 

Die Verbindung wird hiiufig auch als Benzothiazol bezeichnet. Die hier verwendeten Namen 1,3-Benzo-thiazol sowie Areno- und Hetareno[x,y-d]-l,3-thiazol erscheinen jedoch wesentlich eindeutiger, vor allem auch im Hinblick auf die isomeren 1,2- (s. Bd. E8a, S. 799) und 2,1-Benzothiazole (s. Bd. E8a, S. 853) (Benzoisothiazole). 

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