摘要:

AbstractTert.butoxyethyne IV and some 1‐tert.butoxy‐1‐alkynes V have been prepared as outlined in the scheme below. The elimination of HBr from 2‐bromo‐1,2‐unsaturated ethers such as III and VI by means of sodium amide in liquid ammonia gives much better yields of acetylenic ethers than the procedure using KOH. Some examples of this modification of a much used method for the preparation of acetylenic ethers are given. In the case of propynyl ethers CH3C≡COR an excess of sodamide must be avoided, because this isomerizes the propynyl ethers into propargyl ethers HC≡CCH2OR.Tert.butoxyalkynes V split off isobutene at 70–80°, forming cyclobutenone ethers X.The thermal stability of 1‐alkoxy‐1‐alkynes decreases in the ord

ISSN:0165-0513    

DOI:10.1002/recl.19610800802

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe conditions under which a series of trimethylsilylesters of the type, where R=H, CH3, CF3, and C6H5, condense with a number of trimethylsilylamines to form hexamethyl‐disiloxane and an organic amide were investigated. The nature of the R group in the silylester appreciably affected the relative ease of condensation. Addition of an acid catalyst to the reaction system was observed to increase the relative rate of the

ISSN:0165-0513    

DOI:10.1002/recl.19610800803

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe cobalt‐catalyzed decomposition oftert.‐butyl hydroperoxide in the presence of a number of five‐membered heterocycles is described. With tetrahydrofuran displacement of the alpha‐hydrogen atom by a peroxy group is observed; with furan and pyrrole 1.4 addition of peroxy radicals takes place. Thiophen does not react under the conditio

ISSN:0165-0513    

DOI:10.1002/recl.19610800804

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractSeveral organic halides were found to add to Cp2V(II). The reactions of benzyl chloride, ethyl bromide and methyl iodide were studied in detail. Instead of the expected compound Cp2V(IV)RX (X = Cl, Br, I) the tervalent halide Cp2V(III)X was formed exclusively in the presence of excess alkyl halide. When excess Cp2V(II)was present, however, both Cp2V(III)X and Cp2V(III)R were found as reaction products. The following reaction equations are proposed: a) Cp2V + RX → [Cp2VRX]; b) [Cp2VRX] + Cp2V → Cp2VR + Cp2VX; c) Cp2VR + + RX (excess) → Cp2VX + R2. The compounds Cp2V(III)R and Cp2V(III)X were synthesized and the occurrence of reaction c) was demonst

ISSN:0165-0513    

DOI:10.1002/recl.19610800805

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19610800806

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractThe preparation ofTamarindus‐amyloid from seeds ofTamarindus indicaL. is described in detail.The product was homogeneous under conditions of free boundary electrophoresis and of sedimentation in the ultracentrifuge. A tentative value for a molecular weight of 115,000 was found.Partial hydrolysis of the polysaccharide withMyrotheciwn‐cellulase liberated a hepta‐, an octa‐ and a nona‐saccharide, while a fungal enzyme “Luizym” yielded 6‐O‐α‐D‐xylopyranosyl‐D‐glucopyranose.Partial hydrolysis with dilute mineral acid gave the disaccharide 2‐O‐β‐D‐galactopyranosyl‐D‐xylopyranose.Experimental evidence is presented for the following structural features:1A main chain of β 1,4‐linked glucose residues.2.A xylose residue attached by an α 1,6‐linkage to three glucose residues out of every four.3.The three substituted glucose residues and the unsubstituted one alternate regularly.4.The galactose residues are attached to the xylose residues by β 1,2‐linkages.On the basis of this eviden

ISSN:0165-0513    

DOI:10.1002/recl.19610800807

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractPure tetravalent organo‐titanium halides and those titanium alkyls which are formed by a reaction of TiCl4+ organometallic compounds, are unstable and subject to bimolecular disproportionation into 2 TiCl3, an alkane and an olefin, provided an H‐atom on a β‐C‐atom is present in the alkyl group. On the other hand, tetravalent titanium‐alkyls lacking this H‐atom are relatively stable (e.g. TiCl3CH3and neopentyl‐titanium‐trichloride).Chemical evidence has also been advanced in support of two other, subsidiary, bimolecular reactions of titanium alkyls in which, in a concerted reaction, the Ti‐C bonds are broken without previous atom migration taking place in the alkyl groups. In one of these subsidiary reactions the alkyl groups bonded to titanium get directly linked up, with formation of a saturated hydrocarbon and TiCl3. In the other, a titanium alkyl reacts with TiCl4to give an alkylhalide and TiCl3.By performing the disproportionation reaction of TiCl3CD3in heptane, or of titanium alkyls in deuterated cyclohexane, it is demonstrated that no reaction with aliphat

ISSN:0165-0513    

DOI:10.1002/recl.19610800808

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractEthoxyethyne slowly adds diazomethane to yield 4‐ethoxypyrazole I, the structure of which has been proved by synthesis from 1,1,2,3,3‐pentaethoxypropane IV and hydrazine. Ethylthioethyne V, on the contrary, is converted by diazomethane into 3‐ethylthiopyrazole VI, the structure of which has been proved by synthesis from 3‐aminopyrazole X.Ethyl diazoacetate does not react with ethoxyethyne, but can be added to ethylthioethyne, yielding presumably 5‐ethoxycarbonyl‐3‐ethy

ISSN:0165-0513    

DOI:10.1002/recl.19610800809

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

摘要:

AbstractDerivatives of the type (C6H5)3M‐OH, where M  C, Si and Ge, were condensed withN,N‐diethylamino‐trimethylsilane in xylene solvent at 50°. The rates of the condensation reaction for this series (C, Si,Ge) were found to be in the ratio of approximately 1 : 3 : 1, resp

ISSN:0165-0513    

DOI:10.1002/recl.19610800810

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19610800811

出版商:WILEY‐VCH Verlag    

年代:1961

数据来源: WILEY