Butane, 1,4-dichloro

Butane, 1,4-dichloro- (110-56-5), 70, 206 Butanoic acid, 2-diazo-3-oxo-, ethyl ester (2009-97-4), 70, 94 Butanoic add, 4,4,4-trifluoro-3-oxo-2-(triphenylphosphoranylidene)-ethyl ester (83961-56-2), 70, 246... 

Dichloro- 1,3-Dichloro-butane (vie) butane 1,4-Dichloro- butane 2,3-Dichloro-butane (vie)... 

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°. 

Isomeric with non-classical triboretanes of type 3 (Schemes 3.2-3 and 3.2-5) are triboraficyclo] 1.1,0 butanes of type 13 (Scheme 3.2-8). The first derivative 13a was obtained when 4b was reacted with dichloro(trimethylsilylmethyl)borane [19]. 

Solvolysis of butadiene monoxide (10.102) in saline solution is a rather unexpected reaction that further documents this compound s reactivity [168]. In aqueous NaCl solution at physiological pH and temperature, butadiene monoxide disappeared rapidly to form 1,2-dichloro-3,4-epoxybutane (10.111, Fig. 10.25). There was a linear dependence of the rate of reaction on the Cl concentration (in the range investigated (34-135 mM)). The reaction pathway was described as slow solvolytic formation of the bu-tenylchloronium ion, followed by Cl attack to yield Cl2 and butadiene. Cl2 is then rapidly trapped by a second molecule of butadiene monoxide to form a different chloronium ion that also reacts with Cl to yield the final, stable dichloro product (10.111). The formation of 1,2-dichloro-3,4-epoxy-butane under physiological conditions is believed to be toxicologically significant. 

Problem 4.32 Give topological structural formulas for (a) propane, (h) butane, (c) isobutane, (d) 2,2-dimethylpropane, (e) 2,3-dimethylbutane, (/), 3-ethylpentane, (g) l-chloro-3-methylbutane, (h) 2,3-dichloro-2-methylpentane, (/) 2-chloro-2,4,4-trimethylpentane. -4... 

For example, methyl 3-phenylbicyclofl.l.0]butane-l-carboxylate (11, R1 = Ph R2 = C02Me) was converted to methyl 2,2-dichloro-3-phenylbicyclo[l.l.l]pentane-l-carboxylate (12, R1 = Ph R2 = C02Me) in 46% yield on reaction with dichlorocarbene generated by thermolysis of sodium trichloroacetate. 3,14... 

Dehalogenation and related reactions have also been employed in the synthesis of many bicyclobutanes. Sodium induced dechlorination of l,3-dichloro-2,2,4,4-letramethylcyclobu-tane (69) gave 2,2,4,4-tetramethylbicyclo[1.1.0]butane (70) in 47% yield,29 while magnesium also converted l-chloro-3-ethoxy-l-phenyl-2,2,4,4-tetramethylcyclobutane (71) into 1-phenyl-2,2,4,4-tetramethylbicyclo[1.1.0]butane (72) in 40% yield.31 Other typical preparations are summarized in Table 3 25-29-31 35... 

Ni (-)-diop Cl2], (-)-diop - 2,3-0-isopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino)butane Nickel, dichloro[[(2,2-di-... 

Nickel, dichloro [ethylenebis(dimethyl-phosphine)], 58, 133 Nickel, dichloro[ethj lenebis(diphenyl-phosphine)], 58,133 [Ni (-)-diop Cl2 ], (-)-diop=2,3-0-iso-propylidene-2,3-dihydroxy-l,4-bis(di-phenylphosphino)butane, 58, 133 Nickel, dichloro [ trimethylenebis(diphenyl-phosphine)], 58,133 NITRILES, alkylation of, 55, 91 NITRILES FROM KETONES, 58, 101 NITRILES, a vinyl, 55, 99, 101 p-Nitrobenzenesulfonyl cyanide, 57, 89 p-Nitrobenzyl alcohol, 57, 72 p-NITROBENZYL FLUORIDE, 57, 72 Nitro compounds, 56, 36 Nitronates, 56, 36... 

Further improvements in dehalogenation selectivity and yields can be achieved by using dipolar aprotic solvents. Dimethylformamide has mostly been used for this purpose,18,56,84 97 although dimethyl sulfoxide,98,99 especially when combined with sonication at room temperature (vide infra), deserves attention in particular cases.100,101 Other polar and dipolar aprotic solvents have also been used, namely, acetone,4 butan-2-one,4 acetonitrile,102 acetic anhydride,103104 ethyl acetate,61 tetrahydrothiophene 1,1-dioxide (sulfolane)105 and hexamethyl-phosphoric triamide,106 but no details were reported on their advantages over dimelhylform-amide or dimethyl sulfoxide. Better performance of dipolar aprotic solvents, such as dimethyl-formamide, over other solvents has been demonstrated in the recent comparison of the dehalogenation of 4,5-dichloro-4,5,5-trifluoropentan-l-ol (4) with zinc in various solvents.90... 

Butane 2.3-Dichloro-l.1.1.4.4.4-hexafluoro- ElOa. 355 (2 COOH 2CF3)... 

Butane 2.4-Dichloro-hexafluoro-1-(trifluoromethyl-imino)- ElOa. 674 (3-CI- F4 — pv + CoF,)... 

Butane l,2-Dichloro-l,2-difluoro-.V cthoxy- El0b2. 133 (Educt) CftH1(lCI2F20... 

Butane 1.2-Dichloro-pentafluoro-4-((L ifluoro-ethcnyloxy)- E10b2.147 (Educt)... 

Butane 3.4-Dichloro-l-( 1.2-riichIoro-trifluoro-ethoxy)-heptafluoro-E10b,.. 360 (En + C1C E2-CCIF-CF,-CF2-OK)... 

Butane 1-Acetoxy-2,4-dichloro-2-incthyl-3.3.4-trifluoro- EI0b2. 22 (En + Ac-O-Cl)... 

Butane 3,3-Dichloro-4-fluoro-l-phenyl- ElOb, 349F. (En + R-OH/HF)... 

Butane l.l-Dichloro-2.2-difluoro-4-cthoxy-l-(2-pyndy thio)- ElOb,. 620 [C 2C = CF + 2-Thiono I-(0-C0-R)-1.2-H2-py]... 

Recommended surrogate/IS 2-bromo-l-chloropropane and 1,4-dichloro-butane. 

Ru(methallyl)2(cyclooctadiene) is prepared by addition of polymeric dichloro(cy-clooctadiene)ruthenium to a suspension of (2-methylpropenyl)magnesium chloride in diethyl ether, and stirring at room temperature for 1.5 h. After hydrolysis with cold water at -40 °C, the reaction mixture is extracted twice with diethyl ether. Evaporation of the solvent furnishes a gray powder in 80 % yield. This complex (2.0 g, 6.26 mmol) and 2.6 g (6.10 mmol) l,3-bis(diphenylphosphino)butane are... 

CBZ COD Cp Cy DABCO dba DBE DBN DBU DCC DCE DDQ DEA DEAD Dibal-H Diphos-4 DMAP DME 0 II Carbobenzoxy = —COCH2Ph 1,5-Cyclooctadienyl Cyclopentadienyl Cyclohexyl 1.4- Diazabicyclo[2.2.2]octane Dibenzylidene acetone 1.2- Dibromoethane = BrCH2CH2Br 1,8-Diazabicyclo[5.4.0]undec-7-ene 1.5- Diazabicyclo[4.3.0]non-5-ene 1.3- Dicyclohexylcarbodiimide = C6H,3—N=C=N—C6H13 1.2- Dichloroethane = CICH2CH2CI 2.3- Dichloro-5,6-dicyano-1,4-benzoquinone Diethylamine = HN(CH2CH3)2 Diethylazodicarboxylate Diisobutylaluminum hydride 1.4- b s-(Diphenylphosphino)butane 4-Dimethylaminopyridine Dimethoxyethane 0... 

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