摘要:

AbstractA relatively simple method has been developed for the preparation of (cycloprop‐1‐enyl)methylcarbinols from 1‐sodiocyclopropene and epoxides. Satisfactory yields are obtained only with epoxides having at least one unsubstituted epoxy carbon atom.In addition, a method is given for the synthesis of cycloprop‐1‐enylcarbinols from 1‐sodiocyclopropene and ketones. Its applicability is limited by the tendency of the products to polymerize and is restricted to those ketones which have at least one alkyl substituent at each of the carbon atoms adjacent to the carbonyl group. Aldehydes fail to give the correspondin

ISSN:0165-0513    

DOI:10.1002/recl.19730921202

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractTreatment of 8,9‐anhydroerythromycin A 6,9‐hemiacetal with hydrogen peroxide leads to theN‐oxide of the 8,9‐epoxy derivative. The latter compound on catalytic reduction yields 8‐hydroxy‐9‐deoxoerythromycin A, forming the cyclic 6,8‐carbonate in reaction with eth

ISSN:0165-0513    

DOI:10.1002/recl.19730921203

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe synthesis of bis{2,2î‐(5,5î‐dimethoxy)biphenylenephosphonium and bis {2,2′‐(5,5′‐dimethylamino)biphenylene}phosphonium salts is described. The related spiro phosphoranyl radicals II and III, generated by electrochemical reduction, are measured by means of ESR spectroscopy. We observed the same small values of the phosphorus doublet splitting constants as for the bis(2,2′‐biphenylene)phosphoranyl radical I.In this investigation we found also that the radical obtained by photolysis of bis(2,2′‐biphenylene)phosphorane at −120° appeared to be identical with the radical obtained by electrochemical reduction of the bis(2,2′‐biphenylene)phosphonium ion. Irradiation of the phosphorane which has a trigonal bipyramidal (TBP) configuration results in a cleavage of the equatorial hydrogen atom. The small values of the phosphorus doublet splitting constants give rise to a tetrahedron like (T) configuration in which the unpaired electron is delocalized in the aryl ligands.We also discuss the associative character of these radicals in d

ISSN:0165-0513    

DOI:10.1002/recl.19730921204

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractUV irradiation (λ = 265 nm) of 1,3‐cyclohexadiene yields (Z)‐1,3,5‐hexatriene with good efficiency (Φ = 0.41). UV irradiation also effects equilibration between (Z)‐ and (E)‐isomers, be it with rather low quantum yields (ΦZ→E= 0.034; ΦZ→E=0.016). TheZ⇄Eisomerization can be sensitized by triplet sensitizers,e.g.biacetyl. This reaction occurred also upon irradiation of solutions in bromoform with light of 436 nm (So→ T absorption).A simple formula for the calculation of quantum yields from comp

ISSN:0165-0513    

DOI:10.1002/recl.19730921205

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe rate of oxygenation of Rh(PPh3)3Cl in benzene was measured at 50°C. ESR measurements suggest the presence of a Rh(II)·· O2species. A mechanism is proposed for this oxygenation and for the subsequent oxidation of one phosphine liga

ISSN:0165-0513    

DOI:10.1002/recl.19730921206

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractInteraction between di(1‐alkynyl) sulfides (1) and sodium sulfide, selenide or telluride in mixtures of liquid ammonia and methanol or dimethylformamide and methanol gives 1,4‐dithiins (2), 1,4‐thiaselenins (3) and 1,4‐thiatellur

ISSN:0165-0513    

DOI:10.1002/recl.19730921207

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractTreatment ofN,N‐dialkyl‐2,4‐pentadienethioamides (1) with potassiumtert‐butoxide in hexamethylphosphoric triamide causes cyclisation to substituted thiophenes (3)

ISSN:0165-0513    

DOI:10.1002/recl.19730921208

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractProtonated mesityl oxide (1) and 3‐penten‐2‐one (3), and the 2,5,5‐trimethyltetrahydrofuryl (5) and 2,5‐dimethyltetrahydrofuryl (7) ions react with isobutane to give the corresponding saturated ketones andtert‐butyl ion. The reactions are very much faster in 9:1 HF‐SbF5than in HF‐BF3; ions1and5react far more rapidly than3and7, respectively. These “ionic hydrogenations” are concluded to take placeviatransfer of hydride ion from isobutane to the alkylcarbonium carbon of intermediate dications (C,O‐diprotonated alkenones). This mechanism also accounts for the findings that5and7are hydrogenated much more rapidly than1and3, respectively, in spite of the fact that the former ions are thermo‐dynamically far more stable than the latter. The reversibility of these reactions has been demonstrated

ISSN:0165-0513    

DOI:10.1002/recl.19730921209

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractTosyl cyanide reacts under extremely mild conditions with 2,3‐dimethyl‐1,3‐butadiene, isoprene and, under somewhat different conditions, with 1,3‐butadiene. The products, 2‐tosylpyridines and 3,6‐dihydro‐2‐pyridones, are derived by dehydrogenation and hydrolysis, respectively, of the Diels‐Alder cyclo‐adducts formedin situ.Phenylmethanesulfonyl cyanide and 1‐adamantane‐sulfonyl cyanide give analogous results with 2,3‐dimethylbutadiene.At 175°C, tosyl cyanide and tetracyclone form 3,4,5,6‐tetraphenyl‐2‐tosylpyridine. Phenylmethanesulfonyl cyanide andp‐chlorobenze

ISSN:0165-0513    

DOI:10.1002/recl.19730921210

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe polarisability and the equivalent ionic conductance of the short‐chain alkylammonium ions were determined by refractometric and conductometric measurements in aqueous solution

ISSN:0165-0513    

DOI:10.1002/recl.19730921211

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY