Chlorination, chlorosuccinimide sulfuryl chloride

For the formation of 5-chloropyrimidines, AT-chlorosuccinimide is normally the reagent of choice, but several other electrophilic chlorine sources including chlorine gas or sulfuryl chloride can be used <1994HC(52)1>. For example, the chlorination of 4-(trifluoromethyl)-2(l//)-pyrimidinone 59 with ferric chloride and sulfuryl chloride in acetic acid gave the 5-chloro derivative 60 in 80% yield <2004EJ03714>. 

Chlorothieno[3,2-<7]pyrimidin-4(3//)-one 190a (R2 = Cl, R3 = H) was converted to the 8-bromo derivative 285 by heating at 80°C in a mixture of bromine and acetic acid (88USP4725599). Thieno[3,2-d]pyrimidinedione 270 (R = 2 - F, R1 = 4 - Br, R2 = R3 = H) was chlorinated at position 6 by heating at 60°C with sulfuryl chloride in carbon tetrachloride. The reaction worked equally well with N-chlorosuccinimide instead of sulfuryl chloride (93MI1). 

Reagents such as A-bromosuccinimide, A-chlorosuccinimide, ° A-bromocaprolactam, ° sulfuryl chloride, bromine,and <-butyl-hypochlorite have been used to prepare 5-haloisatins. Isatin with ICl gives S-iodoisatin. " Chlorination of 6-chloroisatin and 4-chloroisatingave 5,6- and 4,5-dichloroisatin, respectively. Various alkylisatins also undergo halogenation in the 5-position. ... 

Chlorination /-Butylhypochlorite. Catechyl phosphorus trichloride. N-Chlorosuccinimide. Cupric chloride. N,N-Diethyl-l,2,2-trichlorovinylamine. Iodobenzene dichloride. Mesyl chloride. Sulfuryl chloride. 

Sulfuryl chloride has been used successfully in the preparation of 3-chloroindole [35]. 2,3,5,6-Tetrachloroindole has been used in the preparation of polyhalogenated indole nucleosides. It was prepared from 5,6-dichlorooxindole by conversion to 2,5,6-trichloroindole, then 3-chlorination by iV-chlorosuccinimide [45]. 

V-Chlorosuccinimide is a convenient reagent for the electrophilic substitution and addition of chlorine to organic compounds. Other chlorinating agents of use include Chlorine, Sulfuryl Chloride, Chloramine-T, tert-Butyl Hypochlorite, and Trichloroiso-cyanuric Acid. The primary advantages of using NCS include the ease in handling, the mild conditions under which chlorination proceeds, and the ease of removal of the inoffensive byproduct succinimide. 

Preparative Methods by chlorination of methyl phenylth-ioacetate using sulfuryl chloride or 7V-chlorosuccinimide (NCS) methyl phenylthioacetate (16.8 g) is stirred with powdered NCS (13.3 g) in CCI4 at rt for 10 h, the mixture filtered, the filtrate evaporated, and the residue distilled using a short Vigreux column. ... 

Dichloropyridazine is very susceptible to radical alkylation (23, and this is the key step in making a large number of the needed compounds. Oxidative decarboxylation of carboxylic acids yields 6 and similar compounds, which can then be chlorinated by treatment with sulfuryl chloride, N-chlorosuccinimide, or trichloroisocyanuric acid while irradiating with a sun lamp. Such chlorinations result in multiple products, which then require separation, but this technique also produced... 

Investigations led to the conclusion that A-chlorosuccinimide (NCS) in acetic acid is the reagent of choice for the selective monochlorination of various thiophenes [85]. Other chlorinating agents such as sulfuryl chloride, hypochlorous acid [86], benzyltrimethylammonium tetrachloroiodate [87] or tin(IV) chloride in the presence of lead(IV) acetate [88] were shown to be useful reagents for thiophene chlorination. 

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