United States Patent [19] [11] Patent Number: 5,677,543 Weiss et al. [45] Date of Patent: Oct. 14, 1997 [54] DISSOLVED METHYLLITHIUM- FOREIGN PATENT DOCUMENTS FOR USE IN 0285374 10/1988 European Pat. 01f. - Primary Examiner—Edward A. Miller [75] Inv?ntors: g?zgeygiusfélgg?fléstzlmzl, Attorney, Agent, or Fimz-—Fe1fe 8c Lynch Frankfurt am Main, all of Germany [57] ABSTRACT [73] Assignae: Metaugeseuschaft AG’ Frankfurt am Disclosed is a dissolved methyllithium-containing compo Main, Germany sition for use in synthesis reactions (synthesis composition) and processes of preparing the composition. In the sythesis composition the methyllithium is contained in a solvent of [21] Appl. No.: 499,547 the general formula (I) [22] Filed: Jul. 7, 1995 R1 on3 (I) [30] Foreign Application Priority Data \C/ Jul. 9, 1994 6 [D E] Germany ........................ .. 44 24 222.0 Rz/ \0R4 [2;] ................................... wherein independently R1 and R2 are a hydrogen, methyl or [ 1 _' ‘ ' """""""""""""""""" “ ’ ‘ ethyl residue and R3 and R4 are a methyl or ethyl residue. To Of Search ........................... .- 182-3, prepare the me?lyllithium_containing Synthesis composition . of the invention lithium powder or granular lithium is [56] Refemnces Cited dispersed in a solvent having the general formula 1, methyl U_S_ PATENT DOCUMENTS halide is added at a controlled rate, the reaction temperature 4976 886 12,1990 M _ tal 252/1823 is maintained in the range of from 0° to 60° C., and the , , ornson e . .................. .. - - - - - - ' 5,095,129 3/1992 Ottow et a1. ...... .. 552/510 :gi?i?g hthmm hahde ‘5 Sepmwd from the methym?uum 5,100,575 3/1992 Hatch et al. 252/1823 ' 5,171,467 12/1992 Mehta et al. .. 252/1823 ' 5,523,447 6/1996 Kamienski et al. .............. .. 260/655 R 13 Claims, 3 Drawing Sheets US. Patent Oct. 14, 1997 Sheet 1 0f 3 5,677,543 29 8.:2: r: 229...:q2gm::3N.£25£85218? 53%:as EEELEQZDE51? u - 0'2- 05- 0"9- 0'19 US. Patent Oct. 14, 1997 Sheet 2 of 3 5,677,543 "02 "a "02 "92 "v2 022 * 22 0 L2 "02 "BL "8L "0 "9L "5L -- 'n " u -- ZL -- 0 Methyl-Lithium?iethoxymethon; -- UL I1|1_|l Fig.2 Il| 2200 2000- 0.00 1200:._ 1000 Du-Nr?-JLDLDNCDOT E1000. E1000- 5,677,543 1 2 DISSOLVED ll/IETHYLLITHIUM CONTAINING COMPOSITION FOR USE IN SYNTHESIS REACTIONS BACKGROUND OF THE INVENTION R2 0R4 wherein independently R1 and R2 are a hydrogen, methyl or This invention relates to a new composition for synthesis ethyl residue and R3 and R4 are a methyl or ethyl residue. reactions (synthesis composition). which contains dissolved The composition is useful for synthesis stages and reactions. methyllithium, and to process of preparing said composition. It has surprisingly been found that at storage temperatures 10 Methyllithium is used as a reagent in the preparation of up to room temperature a solution of methyllithium in a solvent having the general formula I will not exhibit sig pharmaceutical products, such as vitamin derivatives or ni?cant changes of its active base content within 100 days steroid derivatives. and in special synthesis stages, such as and that even during a storage at higher temperatures there carbene-type reactions for preparing allenes and will be only a gradual decomposition, which is distinctly alkoxycyclopropanes, methylating reactions for preparing related to the ambient temperature. alkenyllithium compounds and steroidal alkenyl For special stereospeci?c syntheses, a synthesis compo compounds, reducing reactions involving various transition sition is provided which contains also lithium bromide or metal halides, such as PdCl2 to form Pd(0). the preparation lithium iodide. Diethoxymethane is preferably used as a of methyllithium cuprates for use in 1,4-conjugated addi solvent for the methyllithium in the synthesis composition. tions or to prepare other organo-metallic compounds. such 20 In a further embodiment of the invention the solution as MezMg, MeTi(NEt2)3, MesAl, MeaAs or MeaGa. contains a methyllithium-diethoxymethane complex. in Methyllithium is commercially available as an about 5% which methyllithium and diethoxymethane are present in a solution in diethyl ether or as an about 6% solution in diethyl mole ratio ?‘om 120.5 to 1:20. Another methyllithium containing synthesis composition in accordance with the ether, which solution contains about 10% lithium bromide as 25 a complexing stabilizer. The usefulness of the commercially invention is a solution of a methyllithium-diethoxymethane available forms of methyllithium is limited because of the complex in a solvent of the general formula I and/or in a presence of diethyl ether which has a low ?ash point. Other hydrocarbon. preferably in an aromatic hydrocarbon, such as ethereal solutions of methyllithium have no commercial toluene. signi?cance because, on the one hand, they contain meth The dissolved methyllithium-containing synthesis com yllithium only in a very low concentration (about 3 wt-%) position is prepared in accordance with the invention in that and, on the other hand, their stability is inadequate (e.g., in a) lithium powder or granular lithium is dispersed in a THF or glycol ethers). On the other hand, methyllithium is solvent having the general formula I and methyl halide insoluble in hydrocarbons and aromatic compounds. A cer is added at a controlled rate, tain solubility in aromatic compounds can be achieved if the 35 b) the reaction temperature is kept in the range from 0° to methyllithium-THE complex is used (up to 3.74% by 60° C. and weight). For instance, the documents EP-A-0 285 374 and c) the resulting lithium halide is separated from the US. Pat. No. 5,171,467 disclose alkyllithiurn compounds in methyl-lithium solution. aromatic hydrocarbons, which compounds are stabilized by The stoichiometric amount of methyl halide is preferably a content of a Lewis base. such as tetrahydrofuran, and added at a controlled rate to the dispersion of lithiumpowder lithium halides. Since such solutions tend to be decomposed in diethoxymethane over 2 to 6 hours while the reaction due to the metalization of the aromatic compounds, dialky temperature is kept in the range from 15° to 50° C. lrnagnesium compounds are added so that the content of A special synthesis composition for stereochemical reac active lithium compounds is decreased to 2.6% by weight tions is obtained by adding up to 10% by weight lithium and the reactivity is in?uenced by the presence of dialkyl 45 bromide or lithium iodide. magnesium compounds. The process of the invention can be used to prepare It is an object of the invention to provide a dissolved synthesis compositions which contain 5 to 10% methyl methyllithium-containing composition for use in synthesis lithium in solution. ‘The methyllithium solution of the inven reactions (synthesis composition), which has a high stability tion has a high stability and a relatively high concentration in storage and a higher content of methyllithium in solution. 50 thus providing good results when used in the known syn thesis processes. The invention will be explained more in detail in the DESCRIPTION OF THE DRAWINGS following examples. FIG. 1 illustrates a comparison of the dynamic stability EXAMPLEl curves determined by thermogravimetry of a solution of 55 methyllithium in diethyl ether and of a solution of methyl 22.2 g (3200 mmols) lithium powder in 350 g lithium in diethoxymethane (“DEM”); and diethoxymethane (DEM) are provided in a jacketed reactor at an internal temperature T(i) of 35° C. and 80.0 g (1585 FIGS. 2 and 3 represent the stability of in storage of mmols) methyl chloride are added over 5 hours. The reac methyllithium in DEM and of a solution of methyllithium 60 tion heat is dissipated through the jacket. After an after and lithium bromide in DEM at 30° C. reaction time of 30 minutes the reacted suspension is ?ltered to provide a colorless ?ltrate that contains 3.69 rmnols/g THE INVENTION methyllithium. The present invention is in a composition in which the 65 EXAMPLEZ methyllithium is contained in a solvent of the general Example 1 is repeated but granular lithium in DEM is formula (I) used rather than lithium powder and at an internal tempera 5,677,543 3 4 ture T(i) of 25° C. the methyl chloride is added over 315 minutes. After an after reaction time of 30 minutes the suspension is ?ltered through a G4 hit. 368 g of a clear, colorless solution are obtained, which contains 3.86 mmols/g methyllithium. R2 0R4 CONTROL EXAMPLE 1 wherein independently R1 and R2 are a hydrogen. methyl or ethyl residue and R3 and R4 are a methyl or ethyl residue. Example 2 is repeated with the di?erence that the reaction 2. The composition of claim 1 further comprising at least is e?iected in 352 g diethyl ether and 83.8 g (1660 mmols) one of lithium bromide and lithium iodide. methyl chloride are added over 395 minutes. After an after 10 3. The composition of claim 1 wherein the solvent is reaction time of 30 minutes and ?ltration. 341 g of a clear, diethoxymethane. colorless solution of 4.113 mmols/ g methyllithium in diethyl 4. The composition of claim 1 wherein the solution ether are obtained. contains a methyllithium-diethoxymethane complex in EXAMPLE 3 which methyllithium and diethoxymethane are present in a 15 mole ratio of from 1:05 to 1:2.0. 306.5 g of a solution of methyllithium in DEM, which 5. The composition of claim 1, wherein a methyllithium solution has a total base content of 3.55 mmols/g. are diethoxymethane complex is dissolved in a solvent of the provided in a reaction vessel at 25° C. 30 g (345 mmols) general formula I and an aromatic hydrocarbon.