Dichloro-3-buten-2-one

On the other hand, the reactions of 4,4-dichloro-3-buten-2-one (122) with PhS and PhO ions give, respectively, 88% and 100% cis products... 

Dichloro-3-buten-2-one added dropwise with rapid stirring to excess aniline whereupon the mixture starts refluxing by the exothermic reaction, cooled, ether added, and stirring continued 14 hrs. 4,4-dianilino-3-buten-2-one (Y 98%) stirred into 10 parts polyphosphoric acid, and heated 3-4 hrs. at 85-90° 2-anilino-4-methylquinoline (Y 97%). F. e. s. R. L. Soulen et al., J. Org. Ghem. 32, 2661 (1967). 

Fig. 2. Metabolism of model substrates by GST. The following reactions are catalyzed by GST (a) f-chloro-2,4-dinitrobenzene, (b) l,2-dichloro-4-nitrobenzene, (c)r/-a>w-4-phenyl-3-buten-2-one, (d) ethacrynic acid, (e) l,2-epoxy-3-(p-nitrophenoxy)propane, and (f) menaphthyl sulfate.

Annelation l,3-Dichloro-2-butene. 2,3-Dimethyl-2-butylborane. 3,5-Dimethyl-4-chloro-methylisoxazole. Methyl vinyl ketone. (rons-3-Pentene-2-one. Pyrrolidine. 

Dinitro-2-butene may be prepared from 1-chloro-l-nitro-ethane by the same procedure, in 30% yield. The compound melts at 28-28.5° and has a boiling point of 135°/11 mm. Commercially available 1-chloro-l-nitroethane contains about 10% 1,1-dichloro-l-nitro-ethane and 2-chloro-2-nitropropane which cannot be separated by distillation, but these impurities do not interfere with the preparation. Distillation of 2,3-dinitro-2-butene behind safety glass in a nitrogen atmosphere is advisable. The submitters, in preparing this compound, have had one explosion over a period of ten years. 

Volume 75 concludes with six procedures for the preparation of valuable building blocks. The first, 6,7-DIHYDROCYCLOPENTA-l,3-DIOXIN-5(4H)-ONE, serves as an effective /3-keto vinyl cation equivalent when subjected to reductive and alkylative 1,3-carbonyl transpositions. 3-CYCLOPENTENE-l-CARBOXYLIC ACID, the second procedure in this series, is prepared via the reaction of dimethyl malonate and cis-l,4-dichloro-2-butene, followed by hydrolysis and decarboxylation. The use of tetrahaloarenes as diaryne equivalents for the potential construction of molecular belts, collars, and strips is demonstrated with the preparation of anti- and syn-l,4,5,8-TETRAHYDROANTHRACENE 1,4 5,8-DIEPOXIDES. Also of potential interest to the organic materials community is 8,8-DICYANOHEPTAFULVENE, prepared by the condensation of cycloheptatrienylium tetrafluoroborate with bromomalononitrile. The preparation of 2-PHENYL-l-PYRROLINE, an important heterocycle for the synthesis of a variety of alkaloids and pyrroloisoquinoline antidepressants, illustrates the utility of the inexpensive N-vinylpyrrolidin-2-one as an effective 3-aminopropyl carbanion equivalent. The final preparation in Volume 75, cis-4a(S), 8a(R)-PERHYDRO-6(2H)-ISOQUINOLINONES, il lustrates the conversion of quinine via oxidative degradation to meroquinene esters that are subsequently cyclized to N-acylated cis-perhydroisoquinolones and as such represent attractive building blocks now readily available in the pool of chiral substrates. 

The reaction of 2,3-dimethyl-l,3-butadiene with an equimolar amount of chlorine in carbon tetrachloride at — 20 °C has instead been reported593 to give mainly trans-1,4-dichloro-2,3-dimethyl-2-butene and 2-chloromethyl-3-methyl-l,3-butadiene, arising from the loss of one of the acidic hydrogen atoms in the ionic intermediate (equation 28). 

Catalytic asymmetric methylation of 6,7-dichloro-5-methoxy-2-phenyl-l-indanone with methyl chloride in 50% sodium hydroxide/toluene using M-(p-trifluoro-methylbenzyDcinchoninium bromide as chiral phase transfer catalyst produces (S)-(+)-6,7-dichloro-5-methoxy-2-methyl-2--phenyl-l-indanone in 94% ee and 95% yield. Under similar conditions, via an asymmetric modification of the Robinson annulation enqploying 1,3-dichloro-2-butene (Wichterle reagent) as a methyl vinyl ketone surrogate, 6,7 dichloro-5-methoxy 2-propyl-l-indanone is alkylated to (S)-(+)-6,7-dichloro-2-(3-chloro-2-butenyl)-2,3 dihydroxy-5-methoxy-2-propyl-l-inden-l-one in 92% ee and 99% yield. Kinetic and mechanistic studies provide evidence for an intermediate dimeric catalyst species and subsequent formation of a tight ion pair between catalyst and substrate. 

The final series of five procedures presents optimized preparations of a variety of useful organic compounds. The first procedure in this group describes the preparation of 3-BROMO-2(H)-PYRAN-2-ONE, a heterodiene useful for (4+2] cycloaddition reactions. An optimized large scale preparation of 1,3,5-CYCLOOCTATRIENE, another diene useful for [4+2] cycloaddition, is detailed from the readily available 1,5-cyclooctadiene. Previously, the availability of this material has depended on the commercial availability of cyclooctatetraene at reasonable cost. A simple large scale procedure for the preparation of 3-PYRROLINE is then presented via initial alkylation of hexamethylenetetramine with (Z)-1,4-dichloro-2-butene. This material serves as an intermediate for the preparation of 2,5-disubstituted pyrroles and pyrrolidines via heteroatom-directed metalation and alkylation of suitable derivatives. The preparation of extremely acid- and base-sensitive materials by use of the retro Diels-Alder reaction is illustrated in the preparation of 2-CYCLOHEXENE-1.4-DIONE, a useful reactive dienophile and substrate for photochemical [2+2] cycloadditions. Functionalized ferrocene derivatives... 

E)-l-Phenyl-2-buten-l-one added to a little dichloro[( + )-2,2 -bis(diphenylphos-phino)-l,r-binaphthyl]palladium(II) and 2 eqs. 1,1-dichloro-l-phenyl-2,2,2-tri-methyldisilane in benzene at room temp, under N2, the mixture refluxed for 2 h, cooled to —70°, treated with 1.9 M methyllithium in ether, stirred for 10 min then quenched with dil. HCl (S)-l-phenyl-3-(phenyldimethylsilyl)butan-l-one. Y 72% (87% e.e.). F.e. and conversion to p-hydroxyketones, also z //-a-alkyl-j3-hydroxy-derivs. by asym. 1,4-disilylation-alkylation, s. T. Hayashi et al., J. Am. Chem. Soc. 110, 5579-81 (1988) without asym. induction using Pd(PPh3)4 s. Tetrahedron Letters 29, 4147-50 (1988). 

In l,4-dichloro-2-butene, two equivalent sites are available for hydrobora-tion. Both are (3 to one chlorine and y to others and exhibit cumulative effect of (3- and y-chlorine substitution. Employing the data for allyl chloride and 1-chloro-3-methyl-2-butene (Table 4.14) [1], the rate change is calculated as (J,25) 0,1.77) = 44, which is in good agreement with experimentally observed values ofi48. 

Treatment of bis-lactim ether 420 with BuLi, then with cw-l,4-dichloro-2-butene in the presence of Nal afforded 3,4,9,9n-tetrahydro-6//-pyrido[l,2-fl]pyrazin-4-one (421) with 96% diastereomeric excess (97TA1855). Reaction of l,2-diphenyl-6-methyl-quinoxaline with 1,4-dichlorobutane in THF in the presence of Na at —78°C afforded a 3 1 mixture of 4a,5-diphenyl-9-methyl-l,2,3,4-tetrahydro-4a//-pyrido[l,2-n]quinoxaline and 4-(4-chlorobutyl)-2,3-diphenyl-6-methyl-1,4-dihydroquinoxaline (98JHC1349). 

One hundred and twenty-five grams of l,3-dichloro-2-butene (1.0 mole) (Note 4) is added at a rate of about 3 drops per second. Addition should be complete in 0.75-1 hour (Note 5). During the addition the temperature of the oil bath is maintained at 165-170° (Note 6), and the reaction mixture is stirred vigorously. Heating is continued for 1 hour after the addition of dichlorobutene is complete. 

An example of a few of these reactions that occur in our environment with several commonly used pesticides is illustrated in Figures 7-11. Fleck (15) has illustrated in Figure 7 that ultraviolet light catalyzes the decomposition of DDT. In the presence of air, one of the decomposition products is 4,4 -dichlorobenzophenone. However, when air is absent, 2,3-dichloro-l,l,4,4-tetrakis-(p-chlorophenyl)-2-butene is formed. This compound, through subsequent oxidation, may be converted into 4,4 -dichlorobenzophenone. In mammals 2,2-bis(p-chloro-phenyl) acetic acid (DDA) has been identified and shown to be excreted in the feces and urine. The mechanism of formation of DDA is believed to be an initial dehydrochlorination to DDE, which is then hydrolyzed to DDA as shown in Figure 8. Mattson et ah (29) found both DDT and DDE in most samples of human fat, and Walker et ah (44) noted low levels of these same compounds in restaurant meals. 

Hydrolysis of vinyl chlorides. One step in the Wichterle annelation with l,3-dichloro-cw-2-butene (1,214-215 2, 111-112) involves hydrolysis of an intermediate vinyl chloride to a ketone. This reaction has been conducted with cone. H2SO4. A new method involves reaction with mercury(II) trifluoroacetate, which can result in either a methyl or an ethyl ketone depending on the solvent. For example, hydrolysis of 1 with the mercury salt in CH3NO2, CH2CI2, or HOAc gives only the 1,5-diketone 2 in 90-97% yield hydrolysis in CH3OH gives 3 as the major product in 83% yield. ... 

The use of organic halogen compounds as the starting products for the synthesis of other organic chemicals is too immense a field to do more than indicate some of the commercial applications. In his book I4S) on the chemistry of petroleum derivatives, Ellis includes a chapter on the production of alcohols and esters from alkyl halides, and also one on miscellaneous reactions of halo-paraffins and cycloparaffins. The manufacture of amyl alcohols and related products from the chlorides has been well covered 14 ) 1 )-A two-step process for the synthesis of cyclopropane by chlorinating propane from natural gas and dechlorinating with zinc dust was devised in 1936 152). A critical review of syntheses from l,3-dichloro-2-butene was published in Russia in 1950 (1-54). The products obtainable from the allylic chlorides are covered in a number of articles 14If 14 157). 

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