ISSN:0165-0513    

DOI:10.1002/recl.19851040602

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractTreatment of 2‐(diethylamino)‐3‐(methylthio)‐5‐phenyl‐3H‐azepine (3b, R = SMe) with potassium amide in liquid ammonia, followed by reaction of the anion formed with methyl iodide, gave 2‐(diethylamino)‐5‐methyl‐3‐(methylthio)‐5‐phenyl‐5H‐azepine (5a), the structure of which was confirmed by X‐ray analysis. Substitution at position 5 (as well as at C‐3) was also observed on reacting the anion of 2‐(diethylamino)‐5‐phenyl‐3H‐azepine, obtained by deprotonation of its conjugate acid with lithium diisopropylamide in N,N,N′,N′‐tetramet

ISSN:0165-0513    

DOI:10.1002/recl.19851040603

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractCoupling reactions have been conducted between α‐D‐glyco‐ and galacto‐pyranosyl bromide derivatives and 3‐O‐acetyl‐1,6‐anhydro‐2‐azido‐2‐deoxy‐β‐D‐glucopyranose in the presence of insoluble silver salt promoters. It was found that 4‐O‐acyl functions increase the β/α ratio of the disaccharide formation relative to 4‐O‐alkyl functions, whereas 3‐O‐ and 6‐O‐acyl functions decrease this ratio. It was also found that coupling of α‐D‐galactopyranosyl bromide derivatives gave much higher β/α ratios than did reac

ISSN:0165-0513    

DOI:10.1002/recl.19851040604

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractCoupling reactions have been performed in the 2‐deoxy‐2‐azido‐α‐D‐glucopyranosyl bromide series (i.e.compounds2,3, and4) and with the corresponding 2‐O‐methyl and 2‐O‐(2,2,2‐trifluoro‐ethyl)‐substituted α‐D‐glucopyranosyl bromides (i.e.compounds1and7, respectively) using aglycon5in the presence of insoluble silver salt promoters. It was found that coupling of 2‐deoxy‐2‐azido derivatives gave much higher β/α ratios than did the corresponding reactions of the 2‐O‐alkylglucopyranosyl bromides. We assume that through‐bond interactions are responsible for these effects. Other substituent effects are also presented and it is concluded that β‐coupling reactions can be performed in the absence of a participating group at C‐2 if the glycons are appropriately protected. Thus, high β/α ratios may be obtained if acetoxy groups are present at C‐4 and/or 2‐azido‐2‐deoxy functions at C‐2, whereas benzyloxy or allyloxy groups, should be present at C‐3 and C‐6. Furthermore, coupling of galacto‐ and manno‐pyranosyl glycons also gives rise to higher β/α r

ISSN:0165-0513    

DOI:10.1002/recl.19851040605

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractA series of (Z)‐ and/or (E)‐1‐(arylthio)alkenyl isocyanides (1, 2) was synthesized in good yields from (arylthio)methyl isocyanides (4) and either aldehydes or ketones via aPetersonolefination using silylated4as intermediates. Some of the compounds1and2were also prepared via aWittig‐Hornerapproach using diethyl [isocyano(arylthio)methyl]phosphonates (6; not reported previously). Geometrical configurations of the compounds1and2were determined by1H NMR in combination with X‐ray analysis.Compounds1and2constitute a new type of keteneN,

ISSN:0165-0513    

DOI:10.1002/recl.19851040606

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractA general synthesis of tetra‐, tri‐ and dihalosubstituted propellanes is described starting from 1,2‐dimethylenecycloalkanes2to which dichlorocarbene is added to give the expected mono‐addition products3. Flash vacuum thermolysis of3gave the dichlorocyclopentenes4; addition of dichloro‐ or dibromocarbene to4gave the tetrahalo[n.3.1]propellanes1. The tetrachloropropellane1cwas reduced, with one equivalent of triphenyltin hydride, to give the 9‐exo‐trichloropropellane5c; a further equivalent of triphenyltin hydride gave the dichloropropellanes7cand8c. Theendo‐isomer of5cis10c, which was obtained by triphenyltin hydride reduction of4c, followed by dichlorocarbene addition. Finally, triphenyltin hydride reduction of10cgave the dichloropropellanes11cand12c.A conformational analysis of the chloropropellanes was accomplished by means of MNDO calculations on chlorosubstituted bicyclo[3.1.0]hexanes, as model compounds, and by an investigation of the1H NMR spectra. In agreement with literature data, it is concluded that the unsubstituted bicyclo‐[3.1.0]hexane subsystem of the propellanes prefers a flat boat conformation of the overall six‐membered ring, but that the (flat) chair is only slightly higher in energy. The situation is reversed if asyn‐chlorine substituent is introduced into the cyclopropane ring, since transannular repulsions force the five‐membered ring down into the ove

ISSN:0165-0513    

DOI:10.1002/recl.19851040607

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe spin labeled phosphitylating reagent 2‐(tert‐butylsulfonyl)‐ethyl 4‐(2,2,6,6‐tetramethylpiperidine‐1‐oxyl) phosphoromorpholidite (3) rapidly reacts, in the presence of 1‐hydroxybenzotriazole (HOBt), with primary and even secondary hydroxyl functions to give, after oxidation with iodine, a spin labeled phosphotriester, which can be easily deprotected by base to the pertinent spin labeled

ISSN:0165-0513    

DOI:10.1002/recl.19851040608

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19851040609

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19851040601

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY