Lithium- α-lithioacetate and β-lithiopropionate: useful intermediates in organic synthesis
作者:Isidro M Pastor、Miguel Yus
DOI:10.1016/s0040-4039(00)00794-2
日期:2000.7
The reaction of chloroacetic acid and 3-chloropropionic acid with a base (LDA or BunLi, respectively) and then with an excess of lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5%) in the presence of different electrophiles [ButCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe] in THF at −78°C leads, after hydrolysis with water, to the expected hydroxy acids, which in the second case are directly
氯乙酸和3-氯丙酸与碱(分别为LDA或Bu n Li)的反应,然后与过量的锂和催化量的4,4'-二叔丁基联苯(DTBB,5%)反应在不同的亲电子试剂的存在下[卜吨CHO,苯甲醛,等2 CO,(CH 2)5 CO,PhCOMe]在THF中在-78℃下引线,与水水解后,与预期的羟基酸,其中在所述第二在酸性条件下,直接将其环化,得到预期的γ-内酯。
Aldol-type Reactions of Unmasked Iodoacetic Acid with Carbonyl Compounds Promoted by Samarium Diiodide: Efficient Synthesis of Carboxylic 3-Hydroxyacids and Their Derivatives
作者:José M. Concellón、Carmen Concellón
DOI:10.1021/jo060118j
日期:2006.6.1
An easy, direct, general, and efficient samarium diiodide-mediated preparation of 3-hydroxyacids 1 in high yield by reaction of different aldehydes or ketones with commercially available iodoacetic acid is described. The application of different esterification procedures to the crude 3-hydroxyacids so obtained afforded the corresponding 3-hydroxyesters. Also, the cyclization of crude 3-hydroxycarboxylic
Synthesis and antitumour activity of β-hydroxyisovalerylshikonin analogues
作者:Zhen Rao、Xin Liu、Wen Zhou、Jing Yi、Shao-Shun Li
DOI:10.1016/j.ejmech.2011.05.065
日期:2011.9
β-hydroxyisovalerylshikonin analogues bearing oxygen-containing substituents at the side-chain hydroxyl of shikonin were designed and synthesized. The cytotoxicities of these compounds were evaluated in vitro against multi-drug resistant (MDR) cell lines DU-145 and HeLa. Most compounds exhibited significant inhibitory activity on both cell lines. The structure–activity relationship showed the analogues with ether substituents
The present invention relates to a polyurethane polymer comprising as part of its polymer backbone an α-oxy carbonyl moiety of general formula (I), where A and B represent the remainder of the polymer backbone and are the same or different, and R is an optionally substituted aliphatic hydrocarbon having three or more carbon atoms.
Process for the preparation of lactic acid polyesters
申请人:MITSUI TOATSU CHEMICALS, Inc.
公开号:EP0603889A2
公开(公告)日:1994-06-29
[Construction]
In a preparation process of a polyhydroxycarboxylic acid comprising carrying out dehydration polycondensation of hydroxycarboxylic acids which contain at least lactic acid in an organic solvent in the presence or in the absence of a catalyst a preparation process of the polyhydroxycarboxylic acid comprising use of a raw material containing ethyllactate of which amount is 0.3 mole % or less to a reduced mole number of the raw material monomer.
[Effect]
A high molecular weight of polyhydroxycarboxylic acid is obtained with ease and with inexpensive industrially by a direct polycondensation of a hydroxycarboxylic acid which contains at least lactic acid.