Dichloro isomers

Imidazolidinones. Several mono and dichloro isomers have been prepared and tested as disinfectants (157) 1-ch1oro-4,4,5,5-tetramethylimidazo1idin-2-one [58816-19-6] l,3-dichloro-4,4,5,5-tetramethylimidaZohdin-2-one [58816-20-9] (5), mp 102—104°C l-chloro-2,2,5,5-tetramethylimidazohdin-4-one [38951-95-8] mp 157—158°C and l,3-dichloro-2,2,5,5-tetramethylimidazohdin-4-one [128780-87-0] (6), mp 69—71°C (158). In water, these compounds are somewhat less stable but better disinfectants than the oxazoUdinones. They have potential for water disinfection and in hard surface cleaners. l-Bromo-3-chloro- [108602-19-3] mp 102—104°C, and 1,3-dibromo- [108602-18-2] mp 119—121°C, derivatives of 4,4,5,5-tetramethylimidazohdin-2-one have been prepared. 

Chlorination of benzene is an electrophilic substitution reaction in which CL serves as the electrophile. The reaction occurs in the presence of a Lewis acid catalyst such as FeCls. The products are a mixture of mono- and dichlorobenzenes. The ortho- and the para-dichlorobenzenes are more common than meta-dichlorobenzene. The ratio of the mono-chloro to dichloro products essentially depends on the benzene/chlorine ratio and the residence time. The ratio of the dichloro-isomers (0- to p- to m-dichlorobenzenes) mainly depends on the reaction temperature and residence time ... 

Four dichloro isomers, the 1,6-, 2,3-, 2,7-, and 2,8-dichlorodibenzo-p-dioxins, were studied. These compounds also dissolve in TFMS acid, forming cation radicals in the absence of oxidizing agents or UV irradiation. The 2,8-isomer (Figure 5) exhibited a three-line spectrum, in agreement with the two equivalent protons in the 3,6 positions. The 2,7-isomer should also exhibit a three-line spectrum, similar to the 2,8-... 

Methods of synthesis of 3-chloro- and 3,4-dichloro-thiophenes have usually involved tedious procedures in which tri- and tetra-chloro derivatives are dechlorinated by reductive or other methods. Gthanolic potassium hydroxide converted 2,3,4,5-tetrachlorothiophene into a 50 50 mixture of 2,4- and 3,4-dichlorothiophenes direct heating of the same tetrachloro substrate gave a mixture of 2,3- and 2,4-dichloro isomers (48JA1158). 3,4,5-Trichlorothiophene was readily prepared by the reaction of 1,1,2,3-tetrachloro-l,3-butadiene with sulfur (82JOU348). 

Phosphorus oxychloride converts 1,6-naphthyridine 1,6-dioxide to a mixture of 2,5-dichloro-, 3,5-dichloro-, 4,5-dichloro-, and 5-chloro-l,X-naphthyridines (121, 120, 122, and 123, respectively). The 3,5- and 2,5-dichloro isomers are formed as the major products. 

Of the dihalogenobenzenes, the 1,2-dibromo- and dichloro-isomers have been studied in the gas phase by electron diffraction by Bastiansen and Hassel (1947). The diffraction patterns are interpreted in terms of a puckered molecule with the C—Cl bonds bent out of the benzene plane by about 18°. 

The 1,4-dichloro isomer can be isomerized to the 1,2-dichloro isomer by heating with cuprous chloride. 

Scheme 1 shows the hydrolysis and subsequent separation of 1,3- and 1,4-dichloro-decamethylcyclo-hexasilane, which are produced by chlorination with SbCls. The dichloro isomers can easily be regained by chlorination of the products with acetylchloride. Under acidic conditions the hydrolyzed products give oligomeric and polymeric structures, which are subject of the ongoing investigations. 

The fact that the Z-trans AB form was obtained from both dichloro isomers indicates that Basolo s [Co(trien) (en)]Cl3 (1) was the racemic form (trans AB) because his [CotrienCUlCl was also inactive. Nothing can be said of the structure of this complex which was used as starting material because either possible isomer would have led to the inactive trans AB [Cotrien(en)]Cl3 above. He was unsuccessful in resolving the latter, owing to the extreme solubilities of the intermediate salts required. 

Dichloroethyl chloroformate is a known product made by classicai chlorination of vinyl chloroformate with CI2. We have developed a new, easily practicable route by treatment of 4-chloroethylene carbonate with PCI5 at 110°C which gives a mixture of the desired chloroformate and the dichloro isomer in a 95 5 ratio as depicted in scheme 96. Careful fractional distillation afforded the 1,2-dichloroethyl chloroformate in 65 % pure yield (Ref. 125). 

In equilibrium with 3,3-dichlorocyclopropene the product was the ejco-isomer of the 1,3-dichloro isomer. 

The cis (ty2 12 minutes, 25°) and trans (fy2 83 minutes) dibromo complexes hydrolyze rapidly in dilute acidic aqueous solution to give a mixture of cis- and t wis-Co(en)2(OH2)Br]2+4,5 These aquation reactions are about 5-10 times faster than those of the corresponding dichloro isomers. 

We have reported already on the trifluoroacetamide chloride as mainly covalent distillable liquid. This a,a -dichloroamine comproportionates quantitatively on heating to give the a,a -dichloro-isomer in contrast to alkyl or aryl analogs which undergo the von Braun dechloroalkylation (ref. 8, Scheme 8). 

Chlorination of (f )-2-chlorobutane yields a mixture of dichloro isomers. 

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