1461-94-5Relevant articles and documents
Novel synthesis method of lobaplatin intermediate
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, (2021/09/22)
The invention relates to the technical field of drug synthesis, in particular to a novel synthesis method of a loxetine intermediate, which is coupled through low-toxicity dimethyl malonate as a starting raw material. The synthesis of high purity trans -1, 2 - dicyanocyclobutane is carried out after the reaction of bromination, cyclization, hydrolysis, amidation and dehydration. In addition, the yield of the product is greatly improved, so that the cost is greatly reduced, the obtained trans -1 and 2 -dicyanocyclobutane are improved in purity, the subsequent use requirements are completely met, and the market competitiveness is greatly improved.
The synthesis and use in asymmetric epoxidation of metal salen complexes derived from enantiopure trans-cyclopentane- and cyclobutane-1,2-diamine
Daly, Adrian M.,Gilheany, Declan G.
, p. 127 - 137 (2007/10/03)
A complete synthesis of enantiopure trans-cyclopentane-1,2-diamine and trans-cyclobutane-1,2-diamine is described. These diamines have been used as components of novel chiral salen ligands whose chromium and manganese complexes were then evaluated as oxygen transfer agents in the asymmetric epoxidation of alkenes.
Elimination and Addition Reactions. Part 43. Eliminative Fission of Cyclobutanes and the Relationship between Strain and Reactivity in Cyclobutanes and Cyclopropanes
Earl, Harold A.,Stirling, Charles J. M.
, p. 1273 - 1280 (2007/10/02)
Eliminative fission of cyclobutanes has been compared with that of analogous cyclopropanes; reactivity differences of 103.7-104.8 have been determined.In both sets of compounds, mechanisms have been shown to involve rate-determining ring fission.The possibilities that the large reactivity differences between the comparably strained systems are due either to peculiarity in the cyclobutane structures or to their abnormally slow deprotonation are rejected.Analysis of strain in the two systems suggests that as ring fission occurs, dispersal of the excess of enthalpy of the cyclobutanes is a less sensitive function of extension of a bond in the ring than for the cyclopropanes.The behaviour of these systems is compared with cleavage of cyclopropanes and cyclobutanes in other reactions; the results are remarkably similar.Calculations using the MINDO3 programme have been carried out for eliminative fissions of cyclopropylmethyl and cyclobutylmethyl carbanions.These reproduce remarkably closely the difference between the heats of formation of the species at the energy maxima for fission of each ring size; the maximum for fission of the cyclobutane is considerably displaced along the reaction co-ordinate towards product.
