Diastereoselective epoxidation of olefins by organo sulfonic peracids, II
作者:R. Kluge、M. Schulz、S. Liebsch
DOI:10.1016/0040-4020(95)01128-5
日期:1996.2
have investigated the behaviour of sulfonic peracids 2in situ generated towards olefins 7a,7b,9,11,14,16,18, allylic and homoallylic alcohols 20,22,24,26,28,30,33 and α,β-unsaturated ketones 35,37,39. Generally, the epoxidation proceeds in a peracid-like manner with greater diastereoselectivity than those by common oxidants. In particular, the epoxidation of Δ4 3-ketosteroids 39a-i led to 4α,5α-epoxides
Stereoselective expoxidation of allylic and homoallylic alcohols with 30% hydrogen peroxide catalyzed by tungstic acid in buffered media
作者:Denis Prat、Bernard Delpech、Robert Lett
DOI:10.1016/s0040-4039(00)84080-0
日期:1986.1
The aqueous tungstic acid-catalyzed hydrogenperoxideepoxidation of allylicalcohols affords the same major diastereoisomer as the VO(acac)2/tBuOOH system with quite comparable stereoselectivities. In contrast, epoxidation of homoallylic alcohols appears to be much less stereoselective.
Enantioselective synthesis of (+)- and (−)-<i>cis</i>-2-methyl-4-propyl-1,3-oxathiane and their olfactive properties
作者:Wihelm Pickenhagen、Helene Brönner-Schindler
DOI:10.1002/hlca.19840670405
日期:1984.6.20
The enantioselective synthesis of (+)- and (−)-cis-2-methyl-4-propyl-1,3-oxathine 8 and 9 form (E)-2-hezen-1-ol (1) as common starting material is described. The two enantiomeric forms exhibit different organoleptic properties.
Modified ethylene-vinyl alcohol copolymer and method for the production thereof
申请人:——
公开号:US20040096683A1
公开(公告)日:2004-05-20
Provided is a modified ethylene-vinyl alcohol copolymer (C) having an ethylen content of 5 to 55 mol %, which contains a specific structural unit (I) in an amount of 0.3 to 40 mol % and may be obtained by reacting an ethylene-vinyl alcohol copolymer (A) with a monofunctional epoxy compound (B) having a molecular weight of not more than 500. This can be produced by a method for producing the modified ethylene-vinyl alcohol copolymer (C) which comprises melting and kneading an ethylene-vinyl alcohol copolymer (A) with a monofunctional epoxy compound (B) in an extruder. The modified ethylene-vinyl alcohol copolymer (C) is superior to a unmodified ethylene-vinyl alcohol copolymer (A) in transparency, stretchability, flexibility and flexing resistance due to the specific structural unit (I) incorporated therein, and thus, can be used as a barrier material in various applications requiring the above performance capabilities.
Provided is a resin composition comprising 1-99% by weight of a modified ethylene-vinyl alcohol copolymer (C) having an ethylene content of 5-55 mol %, which contains a specific structural unit (I) in an amount of 0.3-40 mol % and can be obtained by reacting an ethylene-vinyl alcohol copolymer (A) with a monofunctional epoxy compound (B) having a molecular weight of not more than 500, and 1-99% by weight of a thermoplastic resin (T
1
) other than (C). Moreover, a multilayer structure in which the resin composition and a thermoplastic resin (T
2
) are laminated is also provided. Thus, a resin composition superior in barrier properties, transparency, stretchability, flexibility, flexing resistance and interlayer adhesiveness and various kinds of molded articles made thereof are provided.