Acetylene, dichloro

Assume that you need to prepare 4 methyl 2 pentyne and discover that the only alkynes on hand are acetylene and propyne You also have available methyl iodide isopropyl bromide and 1 1 dichloro 3 methylbutane Which of these compounds would you choose in order to perform your synthesis and how would you carry it out" ... 

The vinylacetylene [689-97-4] route to chloroprene has been described elsewhere (14). It is no longer practical because of costs except where inexpensive by-product acetylene and existing equipment ate available (see Acetylene-DERIVED chemicals). In the production of chloroprene from butadiene [106-99-0], there are three essential steps, chlorination, isomerization, and caustic dehydrochlorination of the 3,3-dichloro-l-butene, as shown by the following equations Chlorination... 

Acetylene trichloride 1-chloro-2,2-dichloroethylene 1,1 -dichloro-2-chloroethylene ethylene trichloride trichlororide TCE 1,1,2-trichloroethylene trichloroethene... 

Acetylene as well as its compounds have an acetylenic hydrogen atom with an acid character that can be substituted by a chlorine atom. Thus,with acetylene, calcium hypochlorite and sodium hypochlorite in an acid medium form (this can be formed by calcium carbide hydrolysis) chloroacetylene and dichloro-acetylene, which combust spontaneously in air. 

Feoktistov and coworkers 57) found a third mode of reactivity in a closely related system. The electrochemical reduction of the diethyl esters of dichloro-maleic (56) and dichlorofumaric (57) acid was studied. Neither afforded the corresponding acetylene. 

An emulsion, formed during extraction of a strongly alkaline liquor with trichloroethylene, decomposed with evolution of the spontaneously flammable gas, dichloro-acetylene [1]. This reaction could also occur if alkaline metal-stripping preparations were used in conjunction with trichloroethylene degreasing preparations, some of which also contain amines as inhibitors, which could also cause the same reaction [2], Apparently accidental contact of the solvent with potassium hydroxide solution led to generation of flames in the charging port of a stirred reactor [3], See Tetrachloroethylene Sodium hydroxide... 

It is not an inert solvent, and on heating with solid potassium hydroxide or other base, hydrogen chloride is eliminated and chloro- or dichloro-acetylene, which ignite in air, are formed. 

Acyl-substituted quinolizinium ylide 63 was obtained by treatment of its 1,2-dihydro analogue with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ). Its 1,3-dipolar cycloaddition with an acetylenic ester in excess was regioselective and was accelerated in polar solvents yielding the intermediate adduct 64 and finally the corresponding cyclazine 65, as shown in Scheme 2 <2001JOC1638>. 

The reactivity of dichloro carbene towards acetylenic bonds was systematically investigated by Dehmlow19, 20 with respect to substitution of the acetylene, especially those containing additional C-C multiple bonds. It was shown that with aiyl alkyl acetylenes, e.g. 1-phenyl-butyne-l, often the normal cyclopropenone formation occurs only to a minor extent (to yield, e.g. 14), whilst the main reaction consists of an insertion of a second carbene moiety into the original acetylene-alkyl bond (giving, e.g. 15) ... 

The dihalocarbene method was expanded in scope and improved in yield by the introduction of carbenoids of several types. Thus, (dichloro-bromomethyl) phenyl mercury reacted with diaryl acetylenes giving diaryl cyclopropenones in high yields (60—... 

A reinvestigation of the reactions of 3,4-dichloro- and 3-chloroH-hydroxy thiadiazoles with a variety of acetylene nucleophiles (NaC=CNa, I, iC=C-TMS, LiC=C-SnM e3) showed consumption of the starting thiadiazoles with no significant higher molecular weight products being formed <2004TL5441>. 

The iridium complex [Ir(cod)(//2-,PrPCH2CH2OMe)]+BF4 (22) in dichloro-methane at 25 °C at 1 bar H2 is a particularly active catalyst for the hydrogenation of phenyl acetylene to styrene [29]. In a typical experiment, an average TOF of 50 mol mol-1 h-1 was obtained (calculated from a turnover number, TON, of 125) with a selectivity close to 100%. The mechanism of this reaction has been elucidated by a combination of kinetic, chemical and spectroscopic data (Scheme 14.10). 

Most reactive metabolites produced by CYP metabolic activation are electrophilic in nature, which means that they can react easily with the nucleophiles present in the protein side chains. Several functional groups are recurrent structural features in M Bis. These groups have been reviewed by Fontana et al. [26] and can be summarized as follows terminal (co or co — 1) acetylenes, olefins, furans and thiophenes, epoxides, dichloro- and trichloroethylenes, secondary amines, benzodioxoles (methylenediox-yphenyl, MDP), conjugated structures, hydrazines, isothiocyanates, thioamides, dithiocarbamates and, in general, Michael acceptors (Scheme 11.1). 

Synonyms Acetylene dichloride trans-Acetylene dichloride AI3-28786 BRN 1420761 CCRIS 2505 1,2-Dichloroethene ( )-l,2-Dichloroethene trans-Dlchloroethylene l,2- ra/ 5-Dichloro-ethene l,2-trafl5-Dichloroethylene sj/n-Dlchloroethylene Dioform EINECS 205-860-2 NSC 6149 NSC 60512 RCRA waste number U079 UN 1150. 

Synonyms Acetosal Acetosol Acetylene tetrachloride AI3-04597 Bonoform BRN 0969206 Caswell No. 826 CCRIS 578 Cellon l,l-Dichloro-2,2-dichloroethane EPA pesticide chemical code 078601 Ethane tetrachloride NCI-C03554 NSC 60912 RCRA waste number U209 TCE Tetrachlorethane Tetrachloroethane 5j/n-Tetrachloroethane UN 1702 Westron. 

Synonyms Acetylene tetrachloride sym-tetrachloroethane 1,1 -dichloro-2,2 -dichloro-... 

Other li acetylides Li-C=C-R with R = hexyl [21] or benzylether dendrons [22, 23] (up to the fourth generation) have also been attached to (Figure 3.3), and various different electrophiles have been used to complete the reaction with the intermediate li-fuUeride (Scheme 3.2 and Figure 3.3). Besides the protonation, alkyl-, benzyl-, cycloheptatrienyl-, benzoyl- or vinylether-derivatives or formaldehyde and dichloro-acetylene were used as electrophiles [12,20]. Most of these electrophiles are attached to the anion in the expected C-2 position. The 1,4-adducts are available by quenching the anion with the tropylium cation or benzoyl chloride [12]. The fuUerene anion can be stabilized by introduction of benzylether dendrons. The lifetimes of the anions change with the size of the dendrons [22]. 

DICHLORO- ETHYLENE Acetylene Dichloride, Sym-Dichloroethylene, Dioform, cis- or trans- 1,2-Dichloroethylene Flammable Liquid, II 2 3 2... 

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