Aluminium reaction with iodine

By a corresponding reaction with phosphorus oxychloride2 in the presence of aluminium chloride and other catalysts such as ferric chloride, iodine, etc., trichloroethyl phosphate can be prepared in a stepwise fashion. This and related compounds possess the property of reducing the inflammability of organic materials and are recommended for special clothing. 

Compound 85 was dehydrogenated at 300° over palladium black under reduced pressure to a pyridine derivative 96 which was independently synthesized by the following route. Anisaldehyde (86) was treated with iodine monochloride in acetic acid to give the 3-iodo derivative 87. The Ullmann reaction of 87 in the presence of copper bronze afforded biphenyldialdehyde (88). The Knoevenagel condensation with malonic acid yielded the unsaturated diacid 91. The methyl ester (92) was also prepared alternatively by a condensation of 3-iodoanisaldehyde with malonic acid to give the iodo-cinnamic acid (89), followed by the Ullmann reaction of its methyl ester (90). The cinnamic diester was catalytically hydrogenated and reduced with lithium aluminium hydride to the diol 94. Reaction with phosphoryl chloride afforded an amorphous dichloro derivative (95) which was condensed with 2,6-lutidine in liquid ammonia in the presence of potassium amide to yield pyridine the derivative 96 in 27% yield (53). 

Fig (10) The iron complex (80), prepared from methyl abietate (79) is converted to compound (81) utilizing standard organic reactions. It was converted to allylic alcohol (82) by treatment with iodine and potassium bicarbonate. The ketone (83) obtained from (82) undergoes aromatization on bromination and dehydrobromination. Yielding (84) whose transformation to lactone (87) is accomplished following the similar procedure adopted for the conversion of (68) to (74). It is converted to pisiferic acid (1) by treatment with aluminium bromide in... 

The Leukart reaction has also been used in the conversion of dehydroepiandro-sterone into 17/3-formylamino-3/3-formyloxyandrost-5-ene, which on reduction with lithium aluminium hydride afforded 3/3-hydroxy-17/3-me thylaminoandrost-5-ene. Acylation with isocaproyl chloride then furnished the N-methyl-N-isocaproyl steroid (197), after selective ester hydrolysis of the initially formed ON-diacyl derivative. The amide (197) was further converted into its 3,5-cyclo-6-ketone via the 3,5-cyclo-6/3-alcohol and thence by reaction with hydrogen bromide into the corresponding 3/3-bromo-5a-6-ketone which upon dehydrobromination furnished a A2-5a-6-ketone and ultimately the 2-monoacetate of the 2/3,3/3-diol (198) after reaction with silver acetate and iodine. Hydrolysis to the 2/3,3/3-diol (198) gave a separable mixture of the 2/3,3/8-dihydroxy-5a- and -5/3-ketones.88... 

In the first fully authenticated dimerization of an aporphine base, reaction of (+)-O-methylbulbocapnine (35) with iodine in ethanol-water produced the salt (36), whose reduction with zinc in sulphuric acid gave ( )-(35). Alternatively, reduction of (36) with lithium aluminium hydride in ether supplied a pair of diastereoisomeric dimers (37). ... 

The metal generally needs to be activated either with some preformed aluminium alkyl or with iodine or AICI3. Propyl and higher alkyl halides, however, give mainly AICI3 and hydrocarbons on reaction with aluminium. The sesquihalides disproportionate... 

The reaction requires the use of a catalyst for the alkaline earth metals, rare earth metals and aluminium. The most common approaches are the use of (in the laboratory practice only) the salts of mercury(II) such as HgC or Hg(OAc)2. Very small portions of these salts cause amalgamation of the metal surface (and thus clean it from the oxide layer) and facilitate the reaction with alcohols. The larger scale synthesis (and thus the industrial one—in the scope of pollution danger) uses the initial addition of solid iodine (1 g or less per 1(X) g ofalkoxide to be prepared). Formation of metal iodide serves both for cleaning the surface and increases also slightly the acidity of alcohols via formation of solvate complexes. In the case of barium, the application of dry ammonia gas has been reported for this purpose (Caulton, 1990 Drake, 1992). The major factor facilitating the reaction ofmetals with alcohols is the solubility of the alkoxides formed. Insoluble alkoxides form a protective layer on the surface of the metal and it hinders the reaction. Even the reaction of sodium with BuOH in toluene may be almost stopped by the formation of poorly soluble NaO Bu. 

Product distributions from the disproportionation of l,l,2,3-tetrachloro-3, 3-difluoropropene (2CFsCFCCl CClj- CFj Ca Cai+CFa,CCI CCIg 2CFCljCCl CCl4- CF,ClCa CCl, + CCl,Ca Ca,) at 50 C with aluminium halides, titanium tetrachloride, and antimony pentachloride have been determined. Formation of the bromo-olefin CF,-CCl CBrCl in the reaction with aluminium bromide was rationalized in trams of the HSAB concept, and related known reactions were interpreted similarly. Replacement of vinylic fluorine by iodine has been shown to occur udien tetrafluoro-ethylene or chlorotrifluoroethylene is treated with methyl iodide and aluminium chloride. ... 

Lewis acid catalyst is normally required when ammonium polyhalides are used, although recourse does not have to be made to strong acids, such as aluminium trichloride. Bromination and iodination reactions are normally conducted in acetic acid in the presence of zinc chloride [32], but chlorination using the ammonium tetrachloroiodate in acetic acid does not require the additional presence of a Lewis acid [33]. Radical chlorination of toluenes by benzyltrimethylammonium tetrachloroiodate in the presence of AIBN gives mixtures of the mono-and dichloromethylbenzenes [34], Photo-catalysed side-chain chlorination is less successful [35], Radical bromination using the tribromide with AIBN or benzoyl peroxide has also been reported [36, 37],... 

Put several crystals of the obtained dry iodine and an aluminium powder into a small porcelain bowl and carefully mix them perform the experiment in a fume cupboardl). Introduce a drop of water into the prepared mixture with the aid of a long tube or rod. What is observed What role is played by the water in the given experiment Write the equation of the reaction. 

A recently published full account of another synthesis [69] of the same alkaloid starting from the /rans-cinnamic ester 264 represented a different approach (ACD -> ACDB) to ( )-lycorine (Scheme 42). An intramolecular Diels-Alder reaction of 264 in o-dichlorobenzene furnished the two diastereomeric lactones 265 (86%) and 266 (5%) involving the endo and exo modes of addition respectively. The transposition of the carbonyl group of 265 to 267 was achieved by reduction with lithium aluminium hydride, followed by treatment of the resulting diol with Fetizon s reagent, which selectively oxidised the less substituted alcohol to give isomeric 5-lactone 267. On exposure to iodine in alkaline medium 267 underwent iodolactonisation to afford the iodo-hydroxy y-lactone 268. The derived tetrahydropyranyl ether... 

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