20192-66-9Relevant academic research and scientific papers
Zinc monoglycerolate as a catalyst for the conversion of 1,3- and higher diols to diurethanes
Kulasegaram, Sanjitha,Shaheen, Uzma,Turney, Terence W.,Gates, Will P.,Patti, Antonio F.
, p. 47809 - 47812 (2015)
A green methodology exploring the scope of diurethane synthesis from diols and urea in the presence of a homogeneous catalyst is described. Past reactions of diurethanes have relied heavily on environmentally corrosive reagents such as phosgene. Prior to this work, we have utilized metal glycerolates as homogeneous catalysts in the glycerolysis of urea. Here we explore the synthetic scope of this system with a variety of diols. The conversion to diurethanes is proposed to proceed via an intermediate zinc bound isocyanate ligand, which rearranges to form the terminal urethane in the case of 1,3- and higher diols in good selectivity and yields. With butane 1,2,4-triol the selectivity is exclusively for the 5-membered carbonate, suggesting that the proximity of the second hydroxyl group is critical in forming the ring.
Convenient synthesis of ethylene carbonates from carbon dioxide and 1,2-diols at atmospheric pressure of carbon dioxide
Kitamura, Tsugio,Inoue, Yusuke,Maeda, Taisei,Oyamada, Juzo
, p. 39 - 45 (2016/01/09)
An efficient and convenient synthesis of ethylene carbonates was achieved by the reaction of carbon dioxide with 1,2-diols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), followed by treatment with 1-bromobutane. This DBU-promoted transformation proceeded at an atmospheric pressure of carbon dioxide at 25 °C and gave ethylene carbonates in good yields.
Lipophilic oligopeptides for chemo- and enantioselective acyl transfer reactions onto alcohols
Mueller, Christian E.,Zell, Daniela,Hrdina, Radim,Wende, Raffael C.,Wanka, Lukas,Schuler, Soeren M. M.,Schreiner, Peter R.
, p. 8465 - 8484 (2013/09/24)
Inspired by the extraordinary selectivities of acylases, we envisioned the use of lipophilic oligopeptidic organocatalysts for the acylative kinetic resolution/desymmetrization of rac- and meso-cycloalkane-1,2-diols. Here we describe in a full account the discovery and development process from the theoretical concept to the final catalyst, including scope and limitations. Competition experiments with various alcohols and electrophiles show the full potential of the employed oligopeptides. Additionally, we utilized NMR and IR-spectroscopic methods as well as computations to shed light on the factors responsible for the selectivity. The catalyst system can be readily modified to a multicatalyst by adding other catalytically active amino acids to the peptide backbone, enabling the stereoselective one-pot synthesis of complex molecules from simple starting materials.
Reactions of oxalyl chloride with 1,2-cycloalkanediols in the presence of triethylamine.
Itaya, Taisuke,Iida, Takehiko,Natsutani, Itaru,Ohba, Masashi
, p. 83 - 86 (2007/10/03)
The relationship between the product patterns and the configurations of 1,2-cycloheptane- and 1,2-cyclooctanediols 9 in the cyclocondensations with oxalyl chloride in the presence of triethylamine at 0 degrees C has been shown analogous to that obtained for 1,2-disubstituted acyclic ethylene glycols 1: cis-1,2-cyclooctanediol (9f) produced the cyclic oxalate 14f as the major product, while trans-1,2-cycloheptanediol (9e) and trans-1,2-cyclooctanediol (9g) formed the cyclic carbonates 12e, g as the major products. On the other hand, the cyclic oxalates 14a-d were formed as the major products from 1,2-cyclopentane- and 1,2-cyclohexanediols regardless of the configuration. These results can be accounted for by assuming the boat-like transition states for cyclizations of the half esters of comparatively rigid five- and six-membered diols 9a--d. The cyclic oxalates 14a, c may be directly formed through the resulting tetrahedral intermediates from cis-diols (9a,c), and the cyclic carbonates 12a,c as the minor products after ring inversion of the tetrahedral intermediates. The tetrahedral intermediates from the trans-isomers 9b, d cannot undergo ring inversion, producing no traces of the cyclic carbonates 12b, d.
Di-tert-butyl dicarbonate and 4-(dimethylamino)pyridine revisited. Their reactions with amines and alcohols
Basel, Yochai,Hassner, Alfred
, p. 6368 - 6380 (2007/10/03)
The reaction of BOC2O in the presence and absence of DMAP was examined with some amines, alcohols, diols, amino alcohols, and aminothiols. Often, unusual products were observed depending on the ratio of reagents, reaction time, polarity of solvent, pK(a) of alcohols, or type of amine (primary or secondary). In reactions of aliphatic alcohols with BOC2O/DMAP, we isolated for the first time carbonic-carbonic anhydride intermediates; this helps explain the formation of symmetrical carbonates in addition to the O-BOC products. In the case of secondary amines, we succeeded to isolate unstable carbamic-carbonic anhydride intermediates that in the presence of DMAP led to the final N-BOC product. The effect of N-methylimidazole in place of DMAP was also examined.
Reaction of various oxiranes and carbon dioxide. Synthesis and aminolysis of five-membered cyclic carbonates
Iwasaki, Takeshi,Kihara, Nobuhiro,Endo, Takeshi
, p. 713 - 719 (2007/10/03)
Various oxiranes reacted with carbon dioxide at 100 °C using lithium bromide as a catalyst under atmospheric pressure to afford the corresponding five-membered cyclic carbonates quantitatively. The rate of the reaction increased as the bulkiness of substituents on the oxirane ring was reduced or an electron-withdrawing group was introduced on the oxirane ring. The stereochemistry of the reaction of oxirane and carbon dioxide was retention without loss of optical purity. When substituted phenylethylene carbonates were reacted with benzylamine, the selectivity to afford secondary alcohol increased as the electron-withdrawing ability of the para-substituent increased.
The Treatment of Some Cyclic Thiocarbonates with Methyl Halide/Propylene Oxide
Patroni, Joseph J.,Stick, Robert V.
, p. 795 - 802 (2007/10/02)
Treatment of thiocarbonates (OCSO) with methyl iodide/propylene oxide at 80 deg can lead smoothly to the carbonate.In some cases, a competing process is the formation of iodo thiocarbonates (OCOSMe), and an explanation is provided for the product distributions observed.The corresponding reactions with methyl bromide and methyl chloride (as methyl chloroformate) are much less efficient.
