摘要:

AbstractThe preparation and probable structure of managanese (III)‐manganate (IV) Mn7O13, 5H2O (a0= 2,84,c0= 7,27 Å) and manganous (II)‐manganate (IV) Mn7O12, 6H2O are described. Both consist of platelets. Digesting in diluted HNO3leads to γ‐MnO2(nsutite). Manganese (III)‐manganate (IV) is much less stable than the sodiummanganese (II, III)‐manganate‐(IV) described earlier and looses water easily when heated or in vacuo. Water loss results in breaking down of the double layer lattice, and the product is only two‐dimensionally ordered, producing only prism reflections on the X ray diagramm. Heating results in a continuous transition to the two‐dimensionally ordered phase, then to a finely divided and very disordered γ‐MnO2, and eventually to a finely divided and disordered β‐MnO2(pyrolusite). The transition is topotactical so far, but further heating produces δ‐Mn2O3without obvious topotactical relations to the earlier products. The so‐called ‘δ‐MnO2’ (birnessite) appears to be a family of finely divided and very disordered varieties of such manganates (IV) with part of the Mn3+substituted by Mn4+. Since such products usually contain remarkable amounts of alkali ions, they are rather varieties of the earlier described sodiummanganese (II, III)‐manganate (IV). A provisional explanation of the streaking in the electron diffractions of these manganate (IV). A provisional explanation of the streaking in the electron diffractions of these manganates (IV) is given. With respect to these results the so‐called ‘δ‐MnO2’ can no longe

ISSN:0018-019X    

DOI:10.1002/hlca.19700530302

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractActivities and mixing functions of the following binary systems at 25° C are discussed: 1. mixtures of tetrahydrofuran with water, methanol, and cyclohexane; 2. mixtures of diethyl ether with water, methanol, and cyclohexane, and 3. mixtures of tetrahydrofuran with diethyl ether. Comparison with similar systems shows that in systems containing methanol, the strongest interactions are formation and breaking of hydrogen bonds between alcohol molecules; interactions between methanol and ether molecules play a minor rǒle. Systems containing water exhibit two main kinds of interaction: formation and breaking of hydrogen bonds between water molecules, and formation of hydrogen bonds between water and ether molecules. Deviations from ideality are larger for diethyl ether than for tetrahydrofuran in water and methanol, and smaller in cyclohexan

ISSN:0018-019X    

DOI:10.1002/hlca.19700530303

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe autoxidation of cuprous copper in aqueous CH3CN is studied spectrophotometrically and by following O2‐as well as H+‐consumption. The rate of the reaction is greatly enhanced by the addition of chelating dicarboxylic acid anions such as oxalate and malonate, at low pH it increases proportional to H+‐concentration. This is explained by proton attack on the coordinated O2‐group in an oxygen adduct. The reaction is of first order with respect to [CuI] and [O2] and proceeds via one‐elect

ISSN:0018-019X    

DOI:10.1002/hlca.19700530304

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe synthesis of 2‐vinyl‐3,4,5,6‐tetrahydrobenzaldehyde (10) is described. This compound equilibrates above 70° with its valence isomer 4,5‐tetramethylene‐2H‐pyran (11) as can be shown bycis‐trans‐isomerization of the double bond in selectively deuterated10. The unstable 2H‐pyran11can be trapped as tetracyanoethylene adduct12.Gas phase pyrolysis of 6‐oxabicyclo [3.1.0] hex‐2‐ene (18) at 400°C leads tocis‐penta‐2

ISSN:0018-019X    

DOI:10.1002/hlca.19700530305

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe structure of the cyclo‐addition products of ketenes (2) and methylcyclopentadiene could not be predicted, since this ketenophile exists as a rapidly equilibrating 45:54:1 mixture of the 1‐ (4), 2‐ (5) and 5‐methyl (6) isomers. We studied this reaction using dimethylketene (2a) with a view to monoterpenoid synthesis. Only two (AandB) of the many possible cyclo‐adducts were formed in good yield. Using three methods to generate dimethylketene, the ratios ofA:Bwere 90:6, 77:16 and 55:31 respectively.The structures ofAandBwere proved without making use of the known ketene cyclo‐addition rules: Of the many possibilities, all but7, 8, 9and10were excluded by the CO and CCCH3IR.‐bands and NMR. signals. Structure7(filifolone) was rejected by the difference of its NMR. spectrum from those of bothAandB, leaving only8,9and10.ForA, structures9and10were eliminated by two chemical approaches: (1) Peracetic acid oxidation of a mixture rich in A resulted in a combination ofBaeyer‐Villigerreaction, epoxidation, and epoxide‐ketone rearrangement affording a C10‐keto‐lactone14, which was cleaved by alkali to acetone and a C7‐keto‐acid18. (2) Another peracetic acid treatment produced a keto‐epoxide 11, which was converted to a diol22and then to a diketo‐aldehyde 23 with an NMR. doublet for the aldehyde proton.Of the two structures (9and10) left forB, the latter was excluded by the NMR. spectrum of keto‐epoxide15isolated from the peracid treatment of a mixture rich inB: A decoupling experiment with15showed that the ‐CH2‐ was placed next to the α‐carbon of the carbonyl function.Thus the major cyclo‐adduct of dimethylketene and methylcyclopentadiene is8, and the minor product is9. This result demonstrates further ketene cyclo‐addition specificities on top of the ones expressed by the three known rules. The different ratios of8:9are considered to be due to varyingly effective competition between the preliminary interconversion of the methylcyclopentadienes and their cyclo‐addition of dimethylkctene.A number of other oxidation and reduction products of8are described. One of them proved that C7 had migrated in theBaeyer‐Villigerreaction.A partial separation of the enantiomers of the major cycloadduct8was achieved. By the use of 0.5 equivalent of three chiral primary amines (31, 32, and 33) to form aSchiffbase, the excess ketone8was in each case distilled off in a chirally enriched form with positive optical rotation. The derived 2.3‐dihydroketone36was shown to have a positiveCottoneffect and, by an application of the

ISSN:0018-019X    

DOI:10.1002/hlca.19700530306

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractA synthesis is described of [1‐D‐serine, 17, 18‐dilysine]‐β‐corticotropin‐(1–18)‐octadecapeptide amide (I), a short chain ACTH analogue which has been found to possess in animals and also in man high and prolonged corticotropic activity. Synthesis was carried out by the fragment condensation approach involving, in the last build‐up step, coupling of the protected sequences 1–10 and 11–18. From the protected octadecapeptide derivative 1–18 the free peptide was obtained in

ISSN:0018-019X    

DOI:10.1002/hlca.19700530307

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractTwo push‐pull‐cyclobutadienes10band10care prepared by reaction of two eq. of the corresponding acetylenes having electrondonating and electronaccepting groups (4) with one eq. of HBF4to cyclic cyanine salts, followed by elimination of HBF4with KOC(CH3)3. These cyclobutadienes, stable in cristalline form at room temperature respectively for a short time (10bRCH3) or for several days (10cROCH3), are extremely reactive in solution towards various nucleophiles and electrophiles. Cleavage of the nascent cyclobutenes leads to butadienes. The cyclobutadienes10dimerise thermally to cyclooctatetr

ISSN:0018-019X    

DOI:10.1002/hlca.19700530308

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

Abstract(+)‐Epoxy‐α‐dihydroionone (2) is formed completely stereospecifically from (+)‐α‐ionone (1). Under the conditions of theWhartonreaction this epoxide gives the expected isomeric allyl alcohols4and5and, surprisingly, the bicyclic allyl alcohol3. The structure and absolute configuration of the reaction products have been established. A common intermediate for the formation of compounds3, 4and5is probably the vi

ISSN:0018-019X    

DOI:10.1002/hlca.19700530309

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractDamascenoneDORICENONE (trade mark applied for byFirmenich&Cie, Geneva).an odoriferous ketone isolated in minute amounts from Bulgarian rose oil (Rosa damascena Mill.) is shown to betrans‐2,6,6‐trimethyl‐1‐crotonoyl‐cyclohexa‐1, 3‐diene (I). A synthesis starting from beta;‐cyclocitral is described for this conspicuous constituent of rose oil, which displays a powerful fragrance. The synthesis of four related, more saturated ketones, damasconesDORINONE (trade mark applied for byFirmenich&Cie, Geneva)., is

ISSN:0018-019X    

DOI:10.1002/hlca.19700530310

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

Abstract(+)‐Carquejanone and (‐)‐isocarquejanone have been described by their IR. spectra and configurationally studied by optical rotatory dispersion and circular dichroism (Cottoneffect). The application of the octant rule confirms the configurations previously assigned byT

ISSN:0018-019X    

DOI:10.1002/hlca.19700530311

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY