Butyl bromide with lithium

Note 2. Commercial butyllithium in hexane as solvent or butylllthium in diethyl ether, prepared from butyl bromide and lithium, can also be used in principle, but we prefer to use ethyllithium because hexane is not easily separable from the rather volatile cumulenic ether and during the reaction of butyl bromide with lithium some octane is formed which cannot be separated from ethoxybutatriene. 

Reduction of aryl bromides with lithium aluminum hydride takes place in tetrahydrofuran solutions at room temperature. It has also been performed with bener results in the presence of di-r-butyl peroxide under UV irradiation or in the presence of titanium tetrachloride (equations 56 and 57). Reduction of bromobenzene with sodium bis(methoxyethoxy)aluminum hydride (Red-Al, Vitride) at 100-115 C gives benzene in 53% yield (Table 4). ... 

It is advisable to carry out derivatization reactions as soon as possible particularly in THF too much delay may give rise to reduced yields owing to reaction of butyl bromide with aryllithium. In most cases this alkylation causes an observable heat effect when the temperature is allowed to reach —10 °C in the case of 0-LiC6H4OCH3, however, this reaction is markedly slower. 0-LiC6H4F eliminates lithium fluoride at temperatures above —40 °C [221]. 

Analysis of Reagent Purity since the concentration of commercial solutions may vary appreciably it is necessary to standardize solutions of the reagent prior to use. A recommended method for routine analyses involves titration of the reagent with s-butyl alcohol using 1,10-phenanthroline or 2,2 -biquinoline as indicator. Several other methods have been described. Preparative Methods may be prepared in high yield fromn-butyl chloride or n-butyl bromide and lithium metal in ether or hydrocarbon solvents. 

To a vigorously stirred suspension of 2 mol of lithium amide in 2 1 of liquid atimonia (see II, Exp. 11) was added in 15 min 1 mol of propargyl alcohol (commercial product, distilled in a partial vacuum before use). Subsequently, 1 mol of butyl bromide was added dropwise in 75 min. After an additional 1.5 h, stirring was stopped and the ammonia was allovied to evaporate. To the solid residue were added 500 ml of ice-water. After the solid mass had dissolved, six extractions with diethyl ether were performed. The (unwashed) combined extracts were dried over magnesium sulfate and then concentrated in a water-pump vacuum. Distillation of the residue through a 40-cm Vigreux column afforded 2-heptyn-l-ol, b.p. 

Linder an atmosphere of argon, a solution of n-butyl bromide (137 g, 1 moll in anhydrous ether (500 ml) is added with stirring to small chips of lithium containing 1-2% of sodium (15.5 g, 2.2 g-atom) in ether (150 mL). The... 

The first example of chemically induced multiplet polarization was observed on treatment of a solution of n-butyl bromide and n-butyl lithium in hexane with a little ether to initiate reaction by depolymerizing the organometallic compound (Ward and Lawler, 1967). Polarization (E/A) of the protons on carbon atoms 1 and 2 in the 1-butene produced was observed and taken as evidence of the correctness of an earlier suggestion (Bryce-Smith, 1956) that radical intermediates are involved in this elimination. Similar observations were made in the reaction of t-butyl lithium with n-butyl bromide when both 1-butene and isobutene were found to be polarized. The observations were particularly significant because multiplet polarization could not be explained by the electron-nuclear cross-relaxation theory of CIDNP then being advanced to explain net polarization (Lawler, 1967 Bargon and Fischer, 1967). 

The low yields, which are observed among styrenyl adducts, reflect a combination of the poor reactivity of the styrene at the low temperature of the reaction. For example, the combination of t-butyl Grignard with the 2,4-bis-OBoc-benzyl alcohol 15 affords the corresponding benzopyran 50 in only 50% yield even when carried out in the presence of 5-10 equivalents of the styrene (method H, Fig. 4.27).27 Yields for substituted benzopyran styrene adducts are still lower (method G, Fig. 4.27). For example, addition of methyl lithium to 2,4-bis-OBoc-benzylaldehyde 5 followed by the addition of the dienophile and magnesium bromide affords benzopyran 51 in a paltry 27% yield. Method F is entirely ineffective in these cases, because the methyl Grignard reagent competes with the enol ether and with styrene 1,4-addition of methyl supercedes cycloaddition. 

An alternative approach to reduce the levels of impurity (VII) would be to have a "transient" existence of the lithio species, so that it reacts instantaneously with trialkyl borate to form the aryl boronate, prior to being quenched by any extraneous proton source to form (VII). Thus, the preparation of boronic acid (II) was improved by changing the order of the reagents. The slow addition of n-butvl lithium also controls the exotherm of the reaction. There was no reaction observed between n-butyl lithium and triisopropyl borate (to form any butyl boronic acid), nor was there any formation of 2-butyl derivative of (VII) formed by reaction between butyl bromide and the lithio species. The reaction is veiy fast and as soon as the addition of n-butyl lithium is completed the reaction is finished. This indicates a rapid transmetallation and instantaneous boronation of the lithio species. The reaction is very much a... 

This procedure is an adaptation of one described by Hauser and Hamrick.3 1,1-DiphenyIpentane has been prepared by the catalytic hydrogenation of 1,1-diphenyl-l-pentene4-6 and in low yield from the reaction of diphenylmcthyl bromide with di-M-butylmercury.7 More recently 1,1-diphenylpentane was prepared by allowing lithium diphenylmethide to react with tri-w-butyl orthophosphate.8... 

Reduce 3,5-dimethoxybenzoic acid with lithium aluminum hydride to 3,5-dimethoxybenzyl alcohol (I), to 10.5 g (I) in 100 ml methylene chloride at 0° C add 15 g PBr3 warm to room temperature and stir for one hour. Add a little ice water and then more methylene chloride. Separate and then dry, evaporate in vacuum the methylene chloride. Add petroleum ether to precipitate about 11.5 g of the benzyl bromide (II). To 9.25 g (II), 15 g Cul, 800 ml ether at 0° C, add butyl (or other alkyl)-Li (16% in hexane), and stir for four hours at 0° C. Add saturated NH4C1 and extract with ether. Dry and evaporate in vacuum the ether (can distill 100/0.001) to get about 4.5 g olivetol dimethyl ether (HI) or analog. Distill water from a mixture of 90 ml pyridine, 100 ml concentrated HC1 until temperature is 210° C. Cool to 140 0 C and add 4.4 g (III) reflux two hours under N2. Cool and pour into water. Extract with ether and wash with NaHC03. Make pH 7 and dry, evaporate in vacuum to get 3.8 g olivetol which can be chromatographed on 200 g silica gel (elute with CHC13) or distill (130/0.001) to purify. 

A 2-1. fouir-necked flask equipped with a sealed, Teflon-paddle stirrer, a merrcury thermometer, a gas inlet tube, and a dropping funnel is charged with 1.21. of anhydrous tetrahydrofuran (Note 1) and 50 g. (7.1-g. atoms) of lithium pieces (Note 2) under an atmosphere of prepurified nitrogen. The stirred mixture is cooled to —20° by means of a dry ice-acetone bath and a mixture of 100 g. (1.00 mole) of methyl methacrylate (Note 3), and 411 g. (3.0 moles) f n-butyl bromide (Note 4) is added dropwise over a period off 3-4 hours. During this addition, an exothermic reaction ensues which is controlled at —20° (Note 5), and on completion of the addition, the vessel is maintained at this temperature, with stirring, for an additional 30 minutes. The contents oF the flask are then liltered with suction through a... 

The reaction of 2,5-disubstituted 3-furyl bromides with butyl-lithium and octafluorocyclopentene in dry tetrahydrofuran (THF) at —78°C gave bis(furyl)ethenes 82 (06JMC4690). Photochrome 83 (05JOC10323, 06EJ03105) (29-46% yield) and a series of its derivatives 84 (55-65%) containing different substituents at position 6 of the ben-zofuran ring were synthesized from 3-bromo-2-methyl-1-benzofuran (08JPP(A)146). 

Interestingly, if the tribromo compound is treated with five equivalents of n-BuLi, then tetralithiation occurs, as was shown by the isolation of an a-butyl-2,4,5-trimethylthio derivative after reaction with excess dimethyl-disulfide [87JCS(P1)1453]. The a-butyl group in the product is derived from reaction of the a-benzyl carbanion with the n-butyl bromide produced by the initial bromine-lithium exchange reaction (Scheme 59). However,... 

The [4+1] annulation of 1-azadienes to pyrroles can also be achieved through their carbonyl iron complexes (Scheme 6). Novel complex (1,4-diphenyl-2-methyl-l-azabutadiene)tricarbonyliron (0) 24 was obtained in 40% yield from the corresponding azadiene 23 and Fe2(CO)9 then nucleophilic attack by methyl lithium and quenching with tert-butyl bromide, as the proton source, gave 2,5-dimethyl-l,3-diphenylpyrrole 26 in 70% yield, probably through the anionic intermediate complex 25 [88TL1425 90JCS(P1)761]. 

For the preparation of MBM, the starting phenol was alkylated to 2-(n)-butoxy-1,4-dimethoxybenzene in methanolic KOH with n-butyl bromide. The benzaldehyde melted at 79.5-81 °C from methanol, and formed a malononitrile derivative that had a melting point of 134.5-135 C. The nitrostyrene from the aldehyde and nitroethane in acetic acid crystallized from methanol with a mp of 71 -72 °C. Lithium aluminum hydride reduction in ether gave the ether-insoluble chloroform-soluble product 4-(n)-butoxy-2,5-dimethoxyamphetamine hydro-... 

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