Acetylenic alcohols halogenation

Acetylene, acids, alcohols, halogens, hydrazine, mercury, oxidizers, selenium, sulfur Acids, ammonia, combustible materials, fluorine, hydrocarbons, metals, organic materials, sugars... 

Acetylene, acids, alcohols, halogens, hydrazine, mercury, oxidizers, selenium, sulfur... 

The vinylmagnesium derivatives (40), obtained by Cu -mediated anft-addition of Grignard reagents to primary a-acetylenic alcohols, can by hydrolysed to ( )-allylic alcohols (41) (Scheme 18) or, if = H, halogenated and then alkylated to yield (Z)-allylic alcohols (42)." Reaction of (40) with carbonyl compounds gives substituted but-2-ene-l,4-diols. ... 

Butenolides and Tetronic Acids.—A number of routes to halogenated butenolides have been reported. Larock and Riefling have described a promising method for the carbonylation of the vinyl chloromercury derivatives (60) of primary and tertiary acetylenic alcohols which produces 3-chlorobutenolide (61) in high yield. 

Stabilized lithium acetyhde is not pyrophoric or shock-sensitive as are the transition-metal acetyhdes. Among its uses are ethynylation of halogenated hydrocarbons to give long-chain acetylenes (132) and ethynylation of ketosteroids and other ketones in the pharmaceutical field to yield the respective ethynyl alcohols (133) (see Acetylene-derived chemicals). 

Simpson and Burt have studied the same reactions in the presence of various amounts of ethanol and have plotted graphs of phosphonate (81 R = Ph) and phenyl acetylene produced against moles of alcohol added. Acetylene in the product reached a maximum (around 60%) when two moles of ethanol were added and stayed fairly constant beyond this, which suggests that the attack-on-halogen contribution to the mechanism is approximately 60%. The rest of the reaction presumably follows some other mechanism and the authors suggest the addition-elimination route (79) in view of the isolation of the phosphonate (83) from the reaction of tri(isopropyl) phosphite with the bromoacetylene (84). 

Halogens, See also Bromine (Br) Chlorine (Cl) Fluorine (F) Iodine (I) higher aliphatic alcohols, 2 5 in N-halamines, 13 98 reactions with acetaldehyde, 1 105 reactions with acetone, 1 163 reactions with acetylene, 1 180 reactions with alkanolamines from olefin oxides and ammonia, 2 125—126 reactions with aluminum, 2 284—285, 349-359... 

Alkyl halides react with nucleophiles, reagents that can supply an electron pair to form a covalent bond, to give a product in which the nucleophile takes the place of the halogen. Table 6.1 gives fifteen examples of such nucleophilic substitution reactions, which can be used to convert alkyl halides to alcohols, ethers, esters, amines, thiols, alkyl cyanides, or acetylenes. 

Thus reaction with alkyl halides such as allyl bromide or pro-pargyl bromide allow for the introduction of oleflnlc2. . or acetylenic side groups onto the phosphazene ring VI, while alcohol leads to the formation of hydrido-phosphazene complexes VII. The hydrogen in these compounds can be replaced with halogen to yield the first series of iodor-phosphazene compounds VIII. 

Vinyl halides are so inert that none has been converted to a fluoride by halogen exchange. Vinyl fluorides have been synthesized from saturated polyhalides by dehalogenation with zinc and by dehydrohalo- genation with alcoholic alkali, and from acetylene by addition of one molecule of hydrogen fluoride.12 18... 

Oxygenated polyvalent iodine compounds are also useful halogenating agents. oc-Iodoepoxides are prepared by reaction of iodosylbenzene diacetate (IBDA) with allyl alcohols (equation 116)832. Iodosylbenzene, activated by triflic acid, adds to acetylenes (equation 1 17)833. PhI(OAc)2 simultaneously iodinates and etherifies phenols (equation 118)834. 

Olefinic acetals, preparation, 263 preparations listed in table 23, 268 a, S-01efinic acetals, preparation, 37 Olefinic acetylenes, addition of alcohols, 233, 266 alkylation, SO partial reduction, 46 preparatioh, 34, 39, 46, 48, 80 preparations listed in table 6, 84 Olefinic acids, addition, of halogen, 107... 

Starch dilaurate is prepared by treating 1 part-of dry starch in 2.5 parts of pyridine and 3 parts of toluene with 5 parts of lauroyl chloride for two hours at 100 . The product is soluble in benzene, chloroform, and halogen derivatives of acetylene, but is insoluble in water, alcohol, and acetone. On evaporation of a benzene-chloroform solution it forms a brittle film. 

The features of Red-Al are the following It easily reduces halogenated derivatives even if acetylenic (Section 2.1) tertiary amides lead to aldehydes (Section 3.2.8) and propargylic alcohols and amines are reduced to corresponding allylic alcohols and amines (Section 4.1). Epoxides remain intact unless they carry an alcohol functional group at the a position The reduction is then regioselective (Section 2.3). Aromatic nitriles are reduced, but aliphatic nitriles are not affected (Section 4.3). 

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