| 释义 |
stereospecific, a. Chem.|ˌstɛriːəʊ-, ˌstɪəriːəʊspɪˈsɪfɪk|
Also stereo-specific.
[f. stereo- + specific a.]
1. a. Of a reaction: = stereoselective a. Also of a catalyst: causing a reaction to be (more) stereoselective.
1949Jrnl. Amer. Chem. Soc. LXXI. 3866/2 The reaction giving rise to the acetates was at least 90% stereospecific since the ratio of the yield of the acid phthalate of racemate I to the yield of the acid phthalates of other alcohols was ten to one. Stereospecificity of even a higher degree was found in the II series. 1957[see atactic a. 3]. 1958Chem. Abstr. LII. 1106 (heading) Isotactic and other stereospecific polymers. 1959Times Rev. Industry Feb. 57/1 Using the stereospecific catalysts developed in Germany by K. Ziegler, Professor Natta in Milan had succeeded in producing, from propylene gas, useful polymers which he characterized as isotactic. 1960Times 19 July (Royal Soc. Tercentenary Suppl.) p. xiv/3 The past decade has seen the emergence of various stereospecific syntheses. 1966Petroleum Handbk. (ed. 5) 215/2 There are two possibilities in building up the polymer chain [of propylene]; the methyl groups can be situated either at random on both sides of the chain or on one side of the chain only (stereospecific polymerization). 1968[see sense 2 below]. 1978J. A. Brydson Rubber Chem. i. 8 Stereospecific catalyst systems..led to the availability of..rubbers with a much more controlled molecular architecture than had been obtained before. 1979Jrnl. Org. Chem. XLIV. 3374 The determination of the configuration at C-24 of the revised structure of oogoniol..was accomplished by the stereospecific synthesis of the model compounds..which contain the oogoniol side chain.
b. Of a polymer, esp. rubber: = stereoregular a.
1959Times 27 Apr. (Rubber Industry Suppl.) p. ii/7 Polymer chemists have long yearned to synthetize such stereo-specific polymers found to occur so prevalently in Nature. 1961[see stereoregular a.]. 1966Petroleum Handbk. (ed. 5) 224/1 In the last few years..a new family of synthetic rubbers—the stereospecific rubbers—have been developed. 1974J. Ford-Smith tr. Heinisch's Dict. Rubber 447/1 Examples of stereospecific polymers are cis-1:4-polyisoprene and cis-1:4-polybutadiene.
2. Of a reaction or process: yielding a product, or having a rate, that depends on the particular stereoisomeric form of the starting material.
1959,1962[see stereoselective a.]. 1968I. L. Finar Org. Chem. (ed. 4). II iv. 126 The term stereospecific reaction has been used in the same sense as stereoselective reaction, but now the tendency is to restrict the use of stereospecific to a reaction in which different stereoisomers produce different products or act at different rates. 1970J. H. Quastel in Ehrenpreis & Solnitsky Neurosci. Res. III. 15 Stereospecific effects are also observed in cerebral amino acid exchange reactions; for example, elevated cerebral L-lysine is more effective than elevated cerebral D-lysine in increasing L-lysine exchange. 1978Biochem. Pharmacol. XXVII. 653/1 The finding that the R-enantiomer of gliflumide binds less strongly [than the S-enantiomer] indicates that antidiabetic drugs are bound to plasma by a stereospecific process.
Hence ˌstereospeˈcifically adv., in a stereospecific manner: ˌstereospeciˈficity, the property or state of being stereospecific.
1949Stereospecificity [see sense 1 a above]. 1955Jrnl. Amer. Chem. Soc. LXXVII. 4567/1 cis-Propenyllithium prepared from cis-2-bromopropene with lithium in ether..reacts stereospecifically with benzaldehyde..to give..the alcohol with the same configuration as that of the starting bromide. 1965Phillips & Williams Inorg. Chem. I. x. 383 Other monomers can be stereo-specifically polymerized. 1970Jrnl. Polymer Sci. A. VIII. 988 The stereospecificity of these catalysts is remarkable since they yield polybutadienes with a very high 1,4 content. 1970J. H. Quastel in Ehrenpreis & Solnitsky Neurosci. Res. III. 15 Studies of the stereospecificity of amino acid uptake in vivo have shown..that the l-amino acid usually penetrates the brain to a greater extent than the corresponding d-isomer. 1979Jrnl. Chem. Soc.: Chem. Comm. 918/2 Oxidation of labelled hexa-1, 5-dienes with permanganate generages four new chiral centres with complete stereospecificity. Ibid. 920/2 The oxidative cycloaddition constitutes a method for the formation, stereospecifically, and in a single step, of four chiral centres from an archiral, acyclic reactant. |