Dichloro chloride

This is another of the very interesting contributions in Tobe s paper. Tobe has studied substitution reactions of the dichloro-bis(ethylenediamine)cobalt(III) ion in methanol, reported the preparation of the supposed solvo intermediate that would be required, and studied the rate of the chloride anion entry into this supposed solvo intermediate. He reports that the lability of methanol in this complex is insufficient to allow the complex to be an intermediate in a substitution process of the dichloro complex. Yet it is possible to obtain, in the case of the dichloro-chloride exchange, a term in the rate law for the free ion. This leads to the conclusion that, in fact, one has a genuinely unimolecular substitution process. 

The isomeric dichloro-chlorides on hydration pass into the diaquo-salts, [Cr en2(H20)2]R3, and by the removal of water from these the corresponding dichloro-chlorides remain. The configuration is established by the behaviour of the salts towards potassium oxalate. The cis-salts react easily with potassium oxalate, giving the oxalato-deriva-tive, [Cr ensC204]R, whereas trans-salts are not acted upon by the oxalate. Further, the oxalato-salt formed gives, on treatment with... 

If an aqueous solution of green irans-diehloro-chloride is left to stand for one or two days the colour changes to red, and on evaporation, after addition of acetic acid, a residue is obtained from which a considerable quantity of isomeric violet eis-dichloro-chloride may be obtained. The change from cis- into iraas-salt is accomplished by evaporating several times an aqueous solution of the violet isomer after addition of hydrochloric acid and mercuric chloride. 

On taking up the residue writh wrater a green crystalline powder remains, which is the double salt of frans-dichloro-chloride, and from this the simple salt is easily obtained (see p. 105). 

The nitrate, [Cr en2Cl2]N03, is precipitated from a concentrated solution of /jYHi.s-dichloro-chloride with concentrated nitric acid. It crystallises in greyish-green needles and is less soluble in water than the chloride.2... 

Ten grams of dl tris(ethylenediamine)chromium (III) thiocyanate monohydrate are heated at 130-135°C in an open Petri dish as for the cts-dichloro chloride (No. 124). The heating may be performed in a sand bath or thermostat oven. When the material lias lost at least 16% of its original weight (theory = 18.4%) the decomposition is complete for practical purposes. The crude material is quickly recrystallised from water at 50-60°C, filtered, then dried in air,... 

Five grams of neutral r-dichloro chloride are stirred to a smooth paste with 5ml of water, and 5ml of pure aniline are added. The mixture is allowed to stand for one hour the color changes from green to red and the reaction mixture almost solidifies. The material is triturated with methanol to a light-red powder, filtered, and washed with ether. The yield is almost quantitative. 

According to Basolo, aerating a mixture of trien and C0CI2, adding 10 mol/dm HCl and evaporating the solution, Sargeson and Searle obtained a crude product which was blue rather than violet and finally obtained pure cis-a dichloro chloride after repeated recrystallizations from boiling 3 mol/dm HCl. 

CiJ-a-[Co(C03)(trien)] CIO4 H2O. Pure cis-a dichloro complex is added to a large volume of 0.013 mol/dm HCIO4 and the solution is stirred until the dichloro chloride is dissolved and aquated to the aquachloro stage (more than one day). Then, excess NaHC03 and NaC104 are successively added. When the mixture is evaporated at room temperature, the perchlorate monohydrate crystallizes out. 

C -P-[Co(C03)(trien)] Cl 1.5 H2O. Treatment of c/s-a-[CoCl2(trien)] Cl with COf in baric solution produces the cis-p carbonate complex a mixture of crude cis-a dichloro chloride and Li2C03 in water is heated with stirring, whereupon the violet... 

The Bart reaction can be carried a stage further. For example, dichloro-phenylarsine, CjHjAsCl, when added to an excess of sodium carbonate solution, gives CjHjAsfONa) this solution, if similarly treated with benzenedia-zonium chloride, affords diphenylarsinic acid, (CjHjjjAsf. OjOH. 

Dichlorobutane. Place 22-5g. of redistilled 1 4-butanediol and 3 ml. of dry pyridine in a 500 ml. three necked flask fitted with a reflux condenser, mechanical stirrer and thermometer. Immerse the flask in an ice bath. Add 116 g. (71 ml.) of redistilled thionyl chloride dropwise fix>m a dropping funnel (inserted into the top of the condenser) to the vigorously stirred mixture at such a rate that the temperature remains at 5-10°. When the addition is complete, remove the ice bath, keep the mixture overnight, and then reflux for 3 hours. Cool, add ice water cautiously and extract with ether. Wash the ethereal extract successively with 10 per cent sodium bicarbonate solution and water, dry with anhydrous magnesium sulphate and distil. Collect the 1 4-dichloro-butane at 55-5-56-5°/14 mm. the yield is 35 g. The b.p. under atmospheric pressure is 154 155°. 

In the reaction of the 1,1-dichloro-l-alkene 611 with phenylzinc chloride, only monoarylation takes place regioselectively to give the (Z)-l-chloro-l-phe-nylalkene 612[468,474],... 

Silyl ethers serve as preeursors of nucleophiles and liberate a nucleophilic alkoxide by desilylation with a chloride anion generated from CCI4 under the reaction conditions described before[124]. Rapid intramolecular stereoselective reaction of an alcohol with a vinyloxirane has been observed in dichloro-methane when an alkoxide is generated by desilylation of the silyl ether 340 with TBAF. The cis- and tru/u-pyranopyran systems 341 and 342 can be prepared selectively from the trans- and c/.y-epoxides 340, respectively. The reaction is applicable to the preparation of 1,2-diol systems[209]. The method is useful for the enantioselective synthesis of the AB ring fragment of gambier-toxin[210]. Similarly, tributyltin alkoxides as nucleophiles are used for the preparation of allyl alkyl ethers[211]. 

Since the exocyclic sulfur is more reactive in the ambident anion than in A-4-thiazoIine-2-thione. greater nucleophilic reactivity is to be expected. Thus a large variety of thioethers were prepared in good yields starting from alkylhalides (e.g.. Scheme 38 (54, 91, 111, 166-179). lactones (54, 160), aryl halides (54, 152. 180, 181), acyl chlorides (54. 149, 182-184). halothiazoles (54, 185-190), a-haloesters (149. 152. 177. 191-194), cyanuric chloride (151). fV.N-dimethylthiocarbamoyl chloride (151, 152. 195. 196), /3-chloroethyl ester of acrylic acid (197), (3-dimethylaminoethyl chloride (152). l,4-dichloro-2-butyne (152), 1,4-dichloro-2-butene (152), and 2-chloro-propionitrile (152). A general... 

Acid Chloride Formation. Monoacid chlorides of maleic and fumaric acid are not known. Treatment of maleic anhydride or maleic acid with various reagents such as phosgene [75-44-5] (qv), phthaloyl chloride [88-95-9] phosphoms pentachloride [10026-13-8] or thionyl chloride [7719-09-7] gives 5,5-dichloro-2(5JT)furanone [133565-92-1] (4) (26). Similar conditions convert fumaric acid to fumaryl chloride [627-63-4] (5) (26,27). NoncycHc maleyl chloride [22542-53-6] (6) forms in 11% yield at 220°C in the reaction of one mole of maleic anhydride with six moles of carbon tetrachloride [56-23-5] over an activated carbon [7440-44-4] catalyst (28). 

The chloronium ion intermediate can react with water to produce the desired propylene chlorohydrin, with chloride ion to produce 1,2-dichloropropane, or with propylene chlorohydrin to produce isomers of dichloro-dipropyl ether. 

Direct halogenation of sucrose has also been achieved using a combination of DMF—methanesulfonyl chloride (88), sulfuryl chloride—pyridine (89), carbon tetrachloride—triphenylphosphine—pyridine (90), and thionyl chloride—pyridine—1,1,2-trichloroethane (91). Treatment of sucrose with carbon tetrachloride—triphenylphosphine—pyridine at 70°C for 2 h gave 6,6 -dichloro-6,6 -dideoxysucrose in 92% yield. The greater reactivity of the 6 and 6 primary hydroxyl groups has been associated with a bulky halogenating complex formed from triphenylphosphine dihaUde ((CgH )2P=CX2) and pyridine (90). 

Condensation of vinyl chloride with formaldehyde and HCl (Prins reaction) yields 3,3-dichloro-l-propanol [83682-72-8] and 2,3-dichloro-l-propanol [616-23-9]. The 1,1-addition of chloroform [67-66-3] as well as the addition of other polyhalogen compounds to vinyl chloride are cataly2ed by transition-metal complexes (58). In the presence of iron pentacarbonyl [13463-40-6] both bromoform [75-25-2] CHBr, and iodoform [75-47-8] CHl, add to vinyl chloride (59,60). Other useful products of vinyl chloride addition reactions include 2,2-di luoro-4-chloro-l,3-dioxolane [162970-83-4] (61), 2-chloro-l-propanol [78-89-7] (62), 2-chloropropionaldehyde [683-50-1] (63), 4-nitrophenyl-p,p-dichloroethyl ketone [31689-13-1] (64), and p,p-dichloroethyl phenyl sulfone [3123-10-2] (65). 

Acid YeUow 23 (31), commonly known as Tartraziae, stiU maintains sales of nearly 0.5 million /yr ia the United States. It was first discovered ia 1884 and is made by coupling equimolar quantities of diazotized sulfarulic acid to 3-carboxy-l- -sulfophenyl)-5-pyrazolone. Other monoazopyrazolone dyes of commercial importance iaclude Acid YeUow 17 (32) (sulfarulic acid — l-(2,5-dichloro-4-sulfophenyl)-3-methyl-5-pyrazolone and Acid YeUow 40 [6372-96-9] (33) (Cl 18950) (p-aminophenol l-(4-chloro-2-sulfophenyl)-3-methyl-5-pyrazolone) foUowed by esterification of the phenoUc hydroxy group with -toluenesulfonyl chloride. 

Dichlorotoluene (2,4-dichloro-l-methylben2ene) constitutes 80—85% of the dichlorotoluene fraction obtained in the chlorination of PCT with antimony trichloride (76) or zirconium tetrachloride (77) catalysts. It is separated from 3,4-dichlorotoluene (l,2-dichloro-4-methylben2ene), the principal contaminant, by distillation. Chlorination of OCT with sulfuryl chloride gives mainly 2,4-dichlorotoluene and small amounts of the 2,3 isomer (78). 

Dichlorotoluene (l,3-dichloro-2-methylben2ene) is prepared from the Sandmeyer reaction on 2-arnino-6-chlorotoluene. Other methods include ring chlorination of -toluenesulfonyl chloride followed by desulfonylation (81), and chlorination and dealkylation of 4-/ f2 -butyltoluene (82) or... 

---