Halogenation homologation

Halogenation of isoxazoles was also first performed with alkyl homologs.When treated with chlorine or bromine and exposed to sunlight or heated, the isoxazole nucleus undergoes halogenation in the 4-position (63 64). 

Many derivatives of phenol are now made by a synthetic process. Homologous series of substituted derivatives have been prepared and tested for antimicrobial activity. A combination of alkyl substitution and halogenation has produced useful derivatives including clorinated phenols which are constituents of a number of proprietary disinfectants. Two ofthe most widely used derivatives are/ -chloro-m-cresol (4-chloro-3-methylphenol, chlorocresol, Fig. 10.7C) which is mostly employed as a preservative at a concentration of 0.1%, and / -chloro-m-xylenol (4-chloro-3,5-dimethylphenol, chloroxylenol. Fig. 10.7C) which is used for skin disinfection, although less than formerly. Chloroxylenol is sparingly soluble in water and must be solubihzed, for example in a suitable soap solution in conjunction with terpineol or pine oil. Its antimicrobial capacity is weak and is reduced by the presence of organic matter. 

L-ascorbic acid and, 25 751 catalytic esterification of, 10 482 in cationic polymerization of cyclic siloxanes, 22 560 cellulose as, 11 266 a-chiral and homologated, 13 669 control methods for, 26 687-690 derived from halogen fluorides,... 

We have studied how closely the /-values for analogous transitions in homologous atoms agree with each other, as predicted [9], (Table 5). The RQDO results show that multiplets and individual lines for transitions in halogen atoms remain the same as long... 

In the absence of a proton donor, the alkoxide ion generated by carbanion addition to the carbonyl function can interact with a carbon-halogen bond in the 8 2 displacement reaction. Reactions of this type have led to some novel carbon chain forming processes. Ketones are converted to homologated enones in good yield by... 

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