摘要:

AbstractA novel synthesis forrac‐pilosinine (6rac) and transformation of (+)‐pilosinine (6) into thepilocarpusalkaloids (+)‐isopilosine (9) and (+)‐pilocarpine (18) are described. By correlationvia5with18the absolute configuration of (+)‐isopilosine (9) is es

ISSN:0018-019X    

DOI:10.1002/hlca.19720550402

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe synthesis of a series of dodecapeptide ethyl esters containingL‐leucine,L‐ala‐nine, glycine andL‐lysine is described. These peptides are suitable carriers for the preparation of haptenic conjugates to be used in antigenicity studies. The strategy for preparing intermediary hexapeptides has been called a two‐phase approach since the elongation of the peptide chain is carried out stepwise in a water‐immiscible organic phase, whereas removal of side‐products and excess reagent is effected by means of a suitably adapted aqueous phase. The method allows an efficient production of relatively large amounts of fully defined pep

ISSN:0018-019X    

DOI:10.1002/hlca.19720550403

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe addition of diphenylcyclopropenone2to several enamines1as described byCiabattoni&Berchtold[1] [2]has been reinvestigated. The products which were previously postulated to be enamines of β‐dicarbonylcompounds9to14have now been shown to be ‘amides’16to20. The reaction does not take the course of a ‘C, C‐insertion’, which would have been useful for ring expansion, but rather of a ‘C, N‐insertion’, which attaches a C3side chain to the α‐carbon of enamines. This conclusion was reached by new interpretations of spectral data and by chemical transformations of old and new products. In the course of this reinvestigation, a new class of products, the amino‐cyclopentenones41, 45 and47, were isolated from the enamine‐cyclopro‐penone‐reaction. Their structures were proven by spectroscopic considerations and by chemical degradation.A systematic representation of these reactions is pr

ISSN:0018-019X    

DOI:10.1002/hlca.19720550404

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe13C NMR. spectra of nonaction have been recorded at 22.6 MHz. Additivityrules, chemical shift reagents and spectra of model compounds enabled a full assignment of the lines to be made. A comparison of the spectra of the nonactin complexes with Na+, K+, Rb+, Cs+, NH4+and Ba2+showed that no H‐bridges between NH4+and the nonactin carbonyls exist. This is corroborated by the infrared spectra of the complexe

ISSN:0018-019X    

DOI:10.1002/hlca.19720550405

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractAlkali stable primary and secondary amines (of the types H2NCH2CH2OPO3Na2, H2NCH2COONa, H2NCH2CH2OH, H3CNHCH2CH2OH, etc.) heated with n mole‐equiv. of a 2‐amino‐1‐alkylsulfuric acid in aqueous solution, in the presence of 2 n mole‐equiv. of NaOH, giverise to a mixture of poly‐aminoalkylated derivatives with an average degree of aminoalkylation close to n. If the amine is insoluble in water, a mixture of water+an alcohol can be used. In the case of N‐methylaminoethylsulfuric acid, the reaction is carried out in a closed vessel since the intermediate N‐methylaziridine boils at 27,5° under normal pressure.These polyaminoalkyl derivatives are capable of being acylated, alkylated, and cyclized. Some stearylated produc

ISSN:0018-019X    

DOI:10.1002/hlca.19720550406

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe preparation of aluminium derivatives containing allyl or methallyl groups is reported. Their reactivity and physical properties are discussed.

ISSN:0018-019X    

DOI:10.1002/hlca.19720550407

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe acid catalysed dienol‐benzene rearrangement of methyl substitutedo‐ andp‐propargylcyclohexadienols (18–22,34and35) was investigated. In the first step water is eliminated to yield the corresponding methyl propargyl benzonium ions (cf. scheme 6,a), which undergo [1s, 2s] sigmatropic rearrangements to give propargylbenzenes (28,29,30,38) and [3s, 4s] sigmatropic rearrangements to give allenylbenzenes (24–27, 40) (cf. schemes 2, 3, 5, 6). [3s, 3s] sigmatropic rearrangements occur only to a small extend. In the rearrangement of 2‐propargyl‐2,4,6‐trimethylcyclohexa‐3,5‐dien‐1‐ol (18) a [1s, 2s] sigmatropic methyl

ISSN:0018-019X    

DOI:10.1002/hlca.19720550408

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractTreated with methylthiomethylenetriphenylphosphorane, 5‐deoxy‐1,2‐O‐iso‐propylidene‐β‐D‐threo‐ and ‐α‐D‐erythro‐furanos‐3‐uloses led with good yields to a mixture of thecis‐transisomers of the corresponding methylthiovinylidenic sugars. There was no inversion of configuration at C(4) with thethero‐furanosulose and a small one (7%) with itserythroisomer. These unsaturated branched‐chain thio‐sugars are useful synthetic intermediates. For examples, the desulfurization‐hydrogenation (RaneyNickel) of each of these alkenes afforded in good yield two 3‐deoxy‐3‐C‐methyl‐pentoses epimeric at C(3) and having the same configuration at C(4) as the starting alkenes. In all cases the isomer formed by attack from the less hinder

ISSN:0018-019X    

DOI:10.1002/hlca.19720550409

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractIm Rahmen der vorliegenden Mitteilung wird über den erstmaligen partialsynthetischen Aufbau des Steroidalkaloids Batrachotoxinin A (23) [4] berichtet. Als Ausgangsmaterial der Synthese diente das 20‐Oxo‐pregnan‐Derivat2, das von uns bereits früher [3] aus dem 18,20‐Lacton1[2] dargestellt w

ISSN:0018-019X    

DOI:10.1002/hlca.19720550410

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractLysine is often inactivated by ‘Maillard‐type’ reactions in food proteins; the values obtained for it by different methods cannot be compared because the chemical behaviour of inactivated lysine is unknown. In this paper, the behaviour of an important form of inactivated lysine, namely its 1‐deoxyketosyl derivatives, during acid hydrolysis as well as on the different assays for available lysine (F‐DNB, TNBS, pipsylchloride and guanidination) is studied. The relative proportions of regenerated lysine and of formed furosine and pyridosine are established as a function of the conditions of hydrolysis. The validity of the methods used to estimate available lysine from its 1‐deoxyketosyl derivatives i

ISSN:0018-019X    

DOI:10.1002/hlca.19720550411

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY