Lithium dimethylamine

Lithium dimethylamine in ether does not react well with t-butyl chloro-acetylene to give the ynamine however, the reaction appears to go easily if the related fluoroacetylene is used or if hexamethylphosphoramide [8] is used in place of ether. 

CH3)2N]3P0. M.p. 4°C, b.p. 232"C, dielectric constant 30 at 25 C. Can be prepared from dimethylamine and phosphorus oxychloride. Used as an aprotic solvent, similar to liquid ammonia in solvent power but easier to handle. Solvent for organolithium compounds, Grignard reagents and the metals lithium, sodium and potassium (the latter metals give blue solutions). 

I he diaryImethanes (105). The protons on the methylene group of lliese compounds are sufficiently acidic to be removed by strong b.ises such as sodium amide or butyl lithium. Alkylation of the resulting carbanion with w-C2-chloroethyl)dimethylamine affords,... 

I. Ethylamine, anhydrous EK Dimethylamine, anhydrous EK Lithium wire MCB... 

Dibromopropane Dimethylamine 6,11-Dihydrodibenz-(b,e>oxepin-11 -one Triphenyl phosphine Hydrogen bromide Butyl lithium ... 

Woodward s strychnine synthesis commences with a Fischer indole synthesis using phenylhydrazine (24) and acetoveratrone (25) as starting materials (see Scheme 2). In the presence of polyphosphor-ic acid, intermediates 24 and 25 combine to afford 2-veratrylindole (23) through the reaction processes illustrated in Scheme 2. With its a position suitably masked, 2-veratrylindole (23) reacts smoothly at the ft position with the Schiff base derived from the action of dimethylamine on formaldehyde to give intermediate 22 in 92% yield. TV-Methylation of the dimethylamino substituent in 22 with methyl iodide, followed by exposure of the resultant quaternary ammonium iodide to sodium cyanide in DMF, provides nitrile 26 in an overall yield of 97%. Condensation of 2-veratryl-tryptamine (20), the product of a lithium aluminum hydride reduction of nitrile 26, with ethyl glyoxylate (21) furnishes Schiff base 19 in a yield of 92%. 

Preparation by reaction of tantalum pentachloride with pure lithium dimethylamide in pentane is unsafe. Initial non-reaction is followed by explosion during manipulation of the slurry. Presence of ether or dimethylamine gives smooth reaction. Stepwise displacement of chlorine, starting with the free amine, is also recommended. 

Dihydrobenzopyran (chromane) and its methyl homologs were reduced by lithium in ethylamine and dimethylamine to 3,4,5,6,7,8-hexahydrobenzo-pyrans in 84.5% yields [424. ... 

Better reagents than lithium aluminum hydride alone are its alkoxy derivatives, especially di- and triethoxyaluminohydrides prepared in situ from lithium aluminum hydride and ethanol in ethereal solutions. The best of all, lithium triethoxyaluminohydride, gave higher yields than its trimethoxy and tris(/er/-butoxy) analogs. When an equimolar quantity of this reagent was added to an ethereal solution of a tertiary amide derived from dimethylamine, diethylamine, W-methylaniline, piperidine, pyrrolidine, aziridine or pyrrole, and the mixture was allowed to react at 0° for 1-1.5 hours aldehydes were isolated in 46-92% yields [95,1107], The reaction proved unsuccessful for the preparation of crotonaldehyde and cinnamaldehyde from the corresponding dimethyl amides [95]. 

Predict the products from opening of the two stereoisomeric epoxides derived from limonene shown below by reaction with (a) acetic acid, (b) dimethylamine, and (c) lithium aluminum hydride. 

A detailed study of the conversion of 3,4-dichloro-l,2,5-thiadiazole into 3,4-diamino-l,2,5-thia-diazole has been carried out <76JHC13>. Reaction with lithium or sodium amide produces only 4% of the diamine together with cyano-containing by-products, a consequence of direct attack on sulfur. Use of a less powerful nucleophile, ammonia or potassium phthalimide, resulted in an increased attack on carbon and produced the diamine in 24% and 66% yields, respectively. Secondary amines, e.g. morpholine <76JOC3l2l> and dimethylamine <72JMC315>, produce the normal displacement products. The reaction of dichlorothiadiazole with potassium fluoride in sulfolane gives a mixture of 3-chloro-4-fluoro and 3,4-difluoro-l,2,5-thiadiazole <82CB2135>. 

Die hier beschriebenc Art der Oxyaminierung ist hoch stereospezifisch so erhalt man z. B. aus ( )- bzw. (Z)-2-Buten mit Dimethylamin als Amin-Komponente (nach reduktiver Deacetylierung des primar gebildeten 3-Acetoxy-2-amino-butans mit Lithium-alanat) threo- bzw- erythro-2-Dimethylconino-3-hydroxy-butan in jeweils 99%iger Reinheit2. 

By the extension of the above-mentioned stereoselective asymmetric addition of alkylithiums to other organolithium reagents such as lithium salts of methyl phenyl sulfide, 2-methylthiazoline, trialkylsilylacetylene, N-nitroso-dimethylamine, and acetonitrile, chiral oxiranes (95) U1), thiiranes (96) nl), acetylenic alcohols (98) 112), and amino alcohols (97) U1) were readily obtained. 

N,N-Dimethylcyclohexylmethylamine has been prepared by reduction of N,N-dimethylcyclohexanecarboxamide with lithium aluminum hydride 2 3 by the action of dimethylformamide on cyclohexanecarboxaldehyde 4 by methylation of cyclohexyl-methylamine3 6 and of N-methylcyclohexylmethylamine by the Clarke-Eschweiler method (treatment with formaldehyde and formic acid) and by the action of dimethylamine on cyclo-hexylmethyl bromide.6... 

Borane-Dimethylamine, 42 Dimethyl phenylsilane, 123 Diphenylsilane, 153 Lithium aluminum hydride-Sodium methoxide, 159 Potassium-Graphite, 252 Raney nickel, 265 Sodium borohydride, 278 Sodium borohydride-Molybdenum(VI) oxide, 279... 

Triethylaluminum, 204 Triisobutylaluminum, 205 Trimethylaluminum, 22, 205 Vilsmeier reagent-Lithium tri-r-butoxy-aluminum hydride, 342 Boron Compounds Alkyldimesitylboranes, 8 Allenylboronic acid, 36 9-Borabicyclo[3.3.1]nonane, 92 Borane-Dimethylamine, 42 Borane-Dimethyl sulfide-Sodium borohydride, 25... 

The lithium aluminum hydride reduction of l-acetyloxy-2-oxindole (287) gave a polymer, but that of the 1-methoxy analogue (288) yielded [78JCS(P1)1117] 1-methoxyindole. Application of this method (83H1797) led to a valuable synthesis of lespedamine 291. Alkylation of 288 by 1,2-dibromoethane and sodium hydride gave a 3,3-spiro derivative, which dimethylamine converted to 289. Reduction with lithium aluminum hydride now gave 290, as a mixture of isomers, which was dehydrated instantly by acid to 291 (see Section 1II,E). 

In another series of experiments, we found that the reaction of N3P3F3C(OC2H )=CH2 with dimethylamine leads to the non-geminal isomers, 2,4-N3P3FA[N(CH3)2]C(OC2H3)=CH2 the same product is obtained from the reaction of ethoxyvinyl lithium with dimethyl-aminopentafluorocyclotriphosphazene. 

Thioxanthene Butyl lithium Sodium borohydride Dimethylamine 1-Methylpiperazine... 

Lithium salt of cyclopenta[6]pyridinyl with [( 5-Cp )ZrCl2] gives the 5-complex 12 (02JCS(D)2995). Cyclopenta[Z ]pyridine with [Zr(NMe2)4] gives 13 in the presence of dimethylamine. 

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