Ethylidene halides

The following qualitative observations on the action of liquid ammonia on organic compounds are mainly by E. C. Franklin and C. A. Kraus, those in brackets are by G. Gore. Aliphatic compounds.—Halides methyl iodide, m. chloroform, reacts, and m. bromoform, m. iodoform, v.s., ethyl bromide and iodide, s. ethylene bromide, s. ethylidene chloride, m. isobutyl bromide, s. amyl bromide, s.s. tribromomethane, v.s. nitrotriohloromethane, m. perehloroethane (n.s.) perchloroethylene (m.) dichloroacetylene (s.). Alcohols methyl, m. ethyl, m. propyl, m. normal butyl,... 

Methyl-l,2,4-triazines 5 are obtained when 5-chloro-l,2,4-triazines are reacted with trimethylsulfoxonium halide and a base, followed by workup with deactivated Raney nickel.185 5-Alkyl-1,2,4-triazines 6 are obtained by reaction of 5-chloro-l,2,4-triazines with ethylidene-triphcnyl-/.5-phosphanes and aqueous workup.185... 

Acetic aldehyde can be formed in a similar way from ethylidene chloride, CH3.CHCI2, but its preparation by this reaction lacks practical value. There is marked difference between the ease with which benzal chloride and ethylidene chloride react with water the presence of the phenyl radical in the former brings about an activity not shown by the aliphatic halide. The choice of the compounds used in the preparation of the two classes of aldehydes is determined, to some extent, by the substances which can be obtained conveniently and at a low price. The alcohols are, in general, the starting point for the preparation of many aliphatic compounds, on account of their reactivity and the fact that they are prepared commercially on a large scale. In the aromatic series, on the other hand, the hydrocarbons are of the greatest importance as a source of other compounds. 

Introduction of the ethylidene moiety was next achieved via a two-step sequence consisting of an aldol reaction of lactam 126 with acetaldehyde, followed by dehydration employing N, N-dicyclohexylcarbodiimide (DCC) and copper(I) chloride in benzene at reflux (Scheme 8). Methanolysis of the lactam in indohne 127, followed by reduction with DIBAL—H, next furnished aUyl alcohol 128. Conversion to an aUyl halide then permitted a base-mediated cyclization to form the tertiary amine 129, a substrate containing the carbon skeleton ofvincorine (18). 

Gomha and Khalil (2012) developed a successful application of ultrasound irradiation for the rapid synthesis of a novel series of 3-[l-(4-substituted-5-(aryldiazenyl) thiazol-2-yl)hydrazono)ethyl]-2//-chromen-2-ones (48) in good yields (72%-76%), via reactions of 2-(l-(2-oxo-2//-chromen-3-yl)ethylidene)thiosemicarbazide (47) and hydrazonoyl halides (39) in dioxane in the presence of a catalytic amount of... 

A full report has appeared on the preparation of ( )-a-alkylidene lactones (116) in very high yields from enolates (115). Such a transformation can also be carried out in one-pot directly from butyrolactone, although yields are somewhat lower. One useful aspect is that (Z)-isomers of (116) are formed predominantly if the reaction is run in the presence of a metal halide such as Cul or ZnQi. In a very preliminary communication, it has been shown that virtually pure )- or (Z)-a-ethylidene butyrolactone can be obtained from... 

Nitrosyl chloride adds to 5-methylene-2-norbornene (126) and to 5-ethylidene-2-norbornene (lOQ to give dimers of the exo,cis-nitrosochlorides. Similarly, norbornene and norbornadiene add without rearrangement and it is concluded that molecular, and not ionic, addition is important. Addition of deuterium halides to norbornene, and bromine to cyanonorbornenes, has been further studied. With cis,cndo-5,6-dicyanonorbornene mainly cis,exo... 

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