摘要:

AbstractSalts of 1,2,4‐triazole and 3‐bromo‐1,2,4‐triazole with Cd, Zn, Co, Ni, Cu and Ag are reported. The compounds have been identified and characterized by chemical analyses, vibrational and electronic absorption spectra. Different coordination possibilities are discussed in view of the observed vibrational spectra. For the salts of 1,2,4‐triazole, 1,2‐bidentate or tridentate coordinations are observed. In the salts of 3‐bromo‐1,2,4‐triazole, bidentate and tridentate coordina

ISSN:0165-0513    

DOI:10.1002/recl.19790980702

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractAb initiocalculations of the thermodynamic stability order of six acyclic unsaturated hydrocarbons are presented. The results are in reasonable agreement with the experimentally observed order in the equilibrium mixture of isomers resulting from the base‐catalyzed isomerizations. The charge distribution and molecular electrostatic potential of two postulated intermediate carbanions involved in these isomerizations are also calculated in order to explain their initial product ratios which have been observed to differ from the thermodynamical order. These properties fail to reproduce the observed kinetic behaviour. Inclusion of polarization does not improve essentially these results. An estimate of the activation entropy on the basis of the shape of the potentials permits of an interpretation in agreement with the observed reactivit

ISSN:0165-0513    

DOI:10.1002/recl.19790980703

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe synthesis of several plumbole derivatives is reported. Monocyclic compounds may be prepared by the reaction of organoaihthio compounds with diorganolead dibromides. Spirocyclic compounds may be formed from the reaction of dilithio compounds with lead(II) chloride. The compounds are characterized by1H NMR and IR spectroscopy.

ISSN:0165-0513    

DOI:10.1002/recl.19790980704

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractReaction of 5‐X‐4‐phenylpyrimidine (X =Br, Cl) with the enolate anions of acetone and acetophenone in liquid ammonia yields 5‐acetonyl‐ and 5‐phenacyl‐4‐phenylpyrimidine, respectively. It is shown that these reactions proceedviaanSRN1 mechanism. Reaction of 5‐X‐4‐phenylpyrimidine (X =Br, Cl) with the enolate anion of pinacolone gives besidesSRN1 substitution, addition of the anion to the N(1)‐C(6)‐azomethine bond. On treatment of 5‐X‐4‐tert‐butylpyrimidine with the enolate anions of acetone, acetophenone or pinacolone, substitution products are formed in very low yields. Addition of potassium to the liquid ammonia or irradiation with near ultraviolet light, however, increases the yields of 5‐substituted 4‐tert‐b

ISSN:0165-0513    

DOI:10.1002/recl.19790980705

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractChemical exchange studies on the tetramethylformamidinium ion lead to anomalous values for the Arrhenius parameters of internal rotation when apolar solvents, high concentrations and nucleophilic anions are used. The deviations cannot be ascribed to ion‐pairing, and might be due to covalent bondin

ISSN:0165-0513    

DOI:10.1002/recl.19790980706

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractAll possible isomers of title compounds5a‐8ahave been prepared. All the routes presented have involved Wittig olefination of dicarbaldehydes5c‐8c. Synthetic aspects as regards the relevant intermediates are discus

ISSN:0165-0513    

DOI:10.1002/recl.19790980707

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractIrradiation of 1,1‐diphenyl‐2‐(o‐vinylphenyl)ethylene (3) leads stereoselectively toendo‐4,5‐diphenylbenzobicyclo[3.1.0]hex‐2‐ene (6). The analogous reaction of the homologous (o‐propenylphenyl)ethylene derivative (4) seems to be less stereoselective, as products 10 and 11 could be isolated. In both cases a photodehydrocyclisation product (7 and 12, respectively) is also found. Possible mechanisms for the photocyclisation reactions are discussed, and the photochemical behaviour of 3 and 4 is compared with that of othero‐vinylstilbenes, prev

ISSN:0165-0513    

DOI:10.1002/recl.19790980708

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractPhotosensitized oxygenation of 19‐norsteroids with a 5–6 double bond proceeds with high stereoselectivity to give, after reduction of the initially formed hydroperoxides, 5α‐hydroxy 6‐enes as the major products. Higher amounts of 6β‐hydroxy 4‐enes, the minor products, are formed than in the case of cholesterol. These results are in agreement with the “ene” mechanism proposed bySchenckandNickonand not with the peroxirane mechanism propose

ISSN:0165-0513    

DOI:10.1002/recl.19790980709

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractPhenylphosphinidene inserts into Ge‐Y bonds (Y = H, C, N, O, P) with formation of germylphosphines with astructure. However some adducts (Y = N, O, P) undergo a thermal redistribution reaction giving particularly bis(trialkylgermyl)phosphines. Insertion reactions of phenylphosphinidene into Si‐P or Ge‐P bonds of 2‐sila or 2‐germaphospholanes lead to a new class of cyclic metalla‐IVb‐diphosphines, the 3‐sila‐ or 3‐germa

ISSN:0165-0513    

DOI:10.1002/recl.19790980710

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe synthesis of a mixture of (+)‐pilocarpine and (+)‐isopilocarpine from L‐histidine is described. Their separation is

ISSN:0165-0513    

DOI:10.1002/recl.19790980711

出版商:WILEY‐VCH Verlag    

年代:1979

数据来源: WILEY