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Chloro derivatives

Clean monochlorination of all possible ring positions in imidazole is most likely to be successful using the lithio precursors, e.g. 1-benzyl-2-lithioimidazole reacts with hexachloroethane to give l-benzyl-2-chloro-imidazole [10, 11] quenching the 2-lithio derivative of 1-tritylimidazole with chlorine, followed by deprotection gives 2-chloroimidazole in 39% yield [Pg.228]


The 7-chloro-derivative, the first of the group to be isolated (1948) is known as chlortetracy-cline. The 5-hydroxy-derivative is oxytetracy-dine. More recently introduced tetracyclines are 6-demethyl-7-chlorotetracycline and 5-hydroxy-6-deoxy-6-methyienetetracycline. [Pg.390]

Formic acid behaves differently. The expected octadienyl formate is not formed. The reaction of butadiene carried out in formic acid and triethylamine affords 1,7-octadiene (41) as the major product and 1,6-octadiene as a minor product[41-43], Formic acid is a hydride source. It is known that the Pd hydride formed from palladium formate attacks the substituted side of tt-allylpalladium to form the terminal alkene[44] (see Section 2.8). The reductive dimerization of isoprene in formic acid in the presence of Et3N using tri(i)-tolyl)phosphine at room temperature afforded a mixture of dimers in 87% yield, which contained 71% of the head-to-tail dimers 42a and 42b. The mixture was treated with concentrated HCl to give an easily separable chloro derivative 43. By this means, a- and d-citronellol (44 and 45) were pre-pared[45]. [Pg.430]

Acetamido-4-methylselenazole can react with mercuric acetate to yield 5-mercuriacetate derivatives that can be converted to the chloro derivatives by the action of sodium chloride. Treatment with potassium iodide leads to reduction regenerating the initial compound with loss of mercury (Scheme 16) (4). [Pg.231]

The use of a-bromoaldehydes, more reactive than the a-chloro derivatives, gives better results (492,512). They have permitted the yields of the cyclization to be increased from 8 to 60% in the latter case. With the higher aldehydes the yields decrease. Thus for 5-f-butylthiazole it is not higher than 7 to 20% (492, 512). On the other hand, cr-bromoaldehydes are particularly difficult to obtain. [Pg.174]

Another group of halogenated fluorescein dyes is prepared by condensing chloro derivatives of phthalic anhydride with resorcinol, followed by bromination or iodination. Thus Phloxine B /78472-87-2] (Acid Red 92, Cl45410) (42) is prepared by condensing tetrachlorophthaUc anhydride with resorcinol followed by tetrabromination. Phloxine B undergoes ethylation to yield the yellowish ted acid dye Cyanosine B [6441-80-1] (43). [Pg.405]

Among the aromatics, it was found that 4-nitroquinoline N-oxide [56-57-5] is a powerful carcinogen producing malignant tumors when painted on the skin of mice (80). It was further estabUshed that the 2-methyl, 2-ethyl, and 6-chloro derivatives of 4-nitro quinoline oxide are also carcinogens (81). [Pg.193]

Diphenylamine has shown activity against the body louse, chiggers, housefly, and, as the chloro derivative, against the red spider mite. Diarylamines have also been reported to have antiradiation activity (48). [Pg.245]

Pyrrohdinone forms alkaU metal salts by direct reaction with alkaU metals or their alkoxides or with their hydroxides under conditions in which the water of reaction is removed. The potassium salt prepared in situ serves as the catalyst for the vinylation of 2-pyrrohdinone in the commercial production of A/-vinylpyrrohdinone. The mercury salt has also been described, as have the N-bromo and N-chloro derivatives (61,62). [Pg.360]

The kinetics of /V-ch1orination of CA iu basic media have been studied by stopdow spectrophotometry (21). The A/-chloro derivatives are the most important commercial products derived from CA. Their av CI2 and other values appear iu Table 2. Trichloroisocyanuric acid [87-90-17, TCCA, or l,3,5-trichloro-j -tria2iQe-2,4,6(lJT,3JT,5J-i)-trione, is obtained iu - 90% yield by cblorination of aqueous trisodium cyanurate, prepared from CA and NaOH iu a 1 3 molar ratio (22). [Pg.418]

Aminotria2ines also form A/-chloro derivatives, eg, sodium tricbloroammelide (25), tetrachloroammeUde (26) and bexacbloromelamine (27). Reaction of aminotria2ines with excess HOCl or CI2O produces TCCA the exocycHc amino groups are converted to NCl (28). TCCA is decomposed to... [Pg.418]

Most uses of chloroisocyanurates are regulated by the EPA under EIERA. Cyanuric acid (or cyanurate) is ultimately the end product of use of chloroisocyanurates in bleaching, sanitizing, and disinfection appHcations. Since the N-chloro derivatives are biocidal, biodegradation studies have centered on the residual CA. Biodegradation occurs (128). [Pg.421]

Direct chlorination of 3,6-dichloropyridazine with phosphorus pentachloride affords 3,4,5,6-tetrachloropyridazine. The halogen is usually introduced next to the activating oxo group. Thus, 1,3-disubstituted pyridazin-6(l//)-ones give the corresponding 5-chloro derivatives, frequently accompanied by 4,5-dichloro compounds as by-products on treatment with chlorine, phosphorus pentachloride or phosphoryl chloride-phosphorus pentachloride. [Pg.20]

Amino-6-chloro-4-methyl- and 3-amino-6-chloro-5-methyl-pyridazine and 3-amino-6-methylpyridazin-4(l//)-one are transformed with sodium nitrite in the presence of acid into the corresponding oxo compounds. If concentrated hydrochloric acid is used, in some instances the corresponding chloro derivatives are obtained as side products. On the other hand, 3-, 4-, 5- and 6-aminopyridazine 1-oxides and derivatives are transformed into stable diazonium salts, which can easily be converted into the corresponding halo derivatives. In this way 3-, 4-, 5- and 6-bromopyridazine 1-oxides, 5-chloropyridazine 1-oxide, 3,4,5-trichloropyridazine 1-oxide and 6-chloropyridazine 1-oxide can be obtained. [Pg.35]

Generally, the reactions of halopyrazines and haloquinoxalines with nucleophiles are believed to proceed by way of addition/elimination sequences, although there are clear-cut examples where this is not the case (see Section 2.14.2.2) and, consistent with a mechanism which involves bond forming, rather than bond breaking, reactions in the rate-determining step, fluoro derivatives are considerably more reactive ca. xlO ) than the corresponding chloro derivatives. [Pg.176]

In the pyrimido[4,5-c]quinoline series the 1-chloro derivative (104) reacts with a variety of nucleophiles (57JCS3718), as does a 2-chloro in (105) in the isomeric pyrimido[5,4-c]quinoline series (66MI21S00). [Pg.214]

In the pyrrole series, ester groups a to nitrogen are more readily hydrolyzed by alkali, but those in a /3 position more readily by acid. A methoxycarbonyl group in the 2-positlon is meta directing thus bromination yields mainly 4-bromo-2-methoxycarbonylpyrrole. Free radical chlorination with f-butylhypochlorite gives the 5-chloro derivative. [Pg.72]

Arylazo-5-pyrazolones are very common products (139 Section 4.04.1.5.2) readily converted into 4-arylazopyrazoles (466 R =H) via the 5-chloro derivatives (466 = Cl)... [Pg.262]

MgBr reagent by an exchange reaction, while the 4-chloro derivative undergoes reductive cleavage (Scheme 90) (63AHC(2)365). [Pg.58]

Hydroxy and mercapto substituents at the 3- and 5-positions can also exist in tautomeric forms (see Section 4.01.5.2) and can be alkylated at either the substituent or the ring nitrogen atom. 3-Methoxy groups are not replaced by nucleophiles, but both 3- and 5-alkylthio groups react readily, as does 3-methoxy-l,2-benzisothiazole. Alkylthio compounds can be oxidized to sulfoxides and sulfones, and the latter readily undergo nucleophilic replacement. All the hydroxy compounds react with phosphorus pentachloride to give the chloro derivatives. [Pg.153]

Diaziridinimines were made analogously. Tri-t-butylguanidine (281) with r-butyl hypochlorite gave (176) in 80% yield. (281) itself is a sufficiently strong base to deprotonate its Af-chloro derivative (69AG(E)448). This procedure also works with methyl- or phenyl-substituted guanidines. [Pg.232]

The submitters have followed the same procedure in preparing the compounds listed below from the corresponding 2-chloro derivatives. The ether extractions and distillation steps were omitted when solid products were obtained. [Pg.47]

Combined available chlorine The concentration of chlorine which is combined with ammonia (NH3) as chloramine or as other chloro derivatives, yet is still available to oxidize organic matter. [Pg.610]

Originally, a C-20 amine (prepared from a bisnorcholanic acid) was converted into its 7V-chloro derivative, dehydrohalogenated to the imine, converted into the A-acetylenanime, reacted with perbenzoic acid, then hydrolyzed to the 17a-hydroxy-20-ketone ... [Pg.187]

The 3-chloro derivative was developed to impart greater acid stability to the azi-dobenzyl ether. It is much more stable to BF3 -Et20, but is cleaved in neat TFA. Conditions used to cleave the azidobenzyl ether also cleave the 4-azido-3-chlorobenzyl ether. ... [Pg.98]

The chloro-derivative [ClAs Mn(CO)2-(/j -C5H5) 2] (shiny black crystals, mp 124°) can now be much more readily obtained by direct reaction of AsCb with [Mn(CO)2-... [Pg.597]


See other pages where Chloro derivatives is mentioned: [Pg.93]    [Pg.172]    [Pg.198]    [Pg.456]    [Pg.458]    [Pg.418]    [Pg.98]    [Pg.209]    [Pg.241]    [Pg.296]    [Pg.50]    [Pg.140]    [Pg.270]    [Pg.160]    [Pg.198]    [Pg.430]    [Pg.258]    [Pg.140]    [Pg.144]    [Pg.153]    [Pg.214]    [Pg.216]    [Pg.252]    [Pg.594]   
See also in sourсe #XX -- [ Pg.233 ]




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1- Chloro-2-propanol derivatives

2-chloro derivatives, hydrolysis

Benzene derivatives, halogen chloro

Borane, derivatives chloro

Chloro-derivatives, reactions

Cyclophosphazenes, alkoxy and mercapto derivatives of chloro

Ethylenes chloro derivatives

Fluorescence labelling of adenine and its derivatives by chloro- or bromoacetaldehyde

From Benzenoid Derivatives by Displacement of Nitro,Chloro and other Groups

Halogen derivatives chloro

Molybdenum, chloro derivatives

Siloxanes, chloro derivatives

Tetracyclines chloro derivative

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