- The kinetic resolution of oxazinones by alcoholysis: access to orthogonally protected β-amino acids
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The catalytic, alcoholytic kinetic resolution of oxazinones is reported. A novel, stereochemically dense cinchona alkaloid-based catalyst can facilitate the highly enantiodiscriminatory (Sup to 101) ring-opening of oxazinones equipped with electrophilic aryl units to generate orthogonally protected β-amino acids for the first time.
- Cronin, Sarah A.,Connon, Stephen J.
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supporting information
p. 7348 - 7352
(2021/09/07)
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- Docetaxel-1,2,3,-triazole compound, and synthetic process and application thereof
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The invention belongs to the technical field of medicine synthesis, and particularly relates to a docetaxel-1,2,3,-triazole compound, and a synthetic process and application thereof. The synthesis process comprises the steps of synthesizing benzyl alcohol and t-butyl acetate into a starting material, obtaining a hand-shaped side chain through a six-step reaction, condensing the starting material and 7-(1,2,3-triazole formate)-10-deacetylbaccatin III, and performing deprotection to obtain the target compound. The docetaxel-1,2,3,-triazole compound, and the synthetic process and the applicationthereof have the advantages of simple synthesis process, low raw material price, high product yield and purity, and green and environment-friendly synthetic process.
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- Acylation of β-Amino Esters and Hydrolysis of β-Amido Esters: Candida antarctica Lipase A as a Chemoselective Deprotection Catalyst
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N-Acylation by lipase A from Candida antarctica (CAL-A) in ethyl butanoate was applied to the kinetic resolution of tert-butyl esters of 3-amino-3-phenylpropanoic acid (E>100), 3-amino-4-methylpentanoic acid (E>100) and 3-aminobutanoic acid (E=60) on 1.0-2.0 m scale. With the N-acylated resolution products, the exceptional ability of CAL-A to hydrolyse amides and bulky tert-butyl esters was then studied. In all N-acylated tert-butyl esters, chemoselectivity favoured the amide bond cleavage. The tert-butyl ester bond was left intact with 3-amino-3-phenylpropanoate, whereas with 3-amino-4-methylpentanoate and 3-aminobutanoate the CAL-A-catalysed hydrolysis of tert-butyl ester followed the amide hydrolysis.
- M?enp??, Harri,Kanerva, Liisa T.,Liljeblad, Arto
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p. 1226 - 1232
(2016/04/05)
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- Derivatives of β-aminopropionic acid with a fungicidal activity
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Compounds based on derivatives of β-aminopropionic acid having the general formula (I): STR1 The compounds having general formula (I) have a high antifungal activity.
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- Physicochemical factors affecting the uptake by roots and translocation to shoots of amine bases in Barley
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The uptake by barley roots from nutrient solution and subsequent transport to shoots of two series of amine bases were measured over 6 to 72 h. The compounds were chosen to span systematically ranges of lipophilicity (assessed using 1-octanol/water partition coefficients, K(ow)) and pKa that would include commercial pesticide amines. In a series of six substituted phenethylamines, strong bases with pKa ~ 9.5, all the compounds were strongly taken up by roots from solutions of pH 8.0; uptake declined substantially as the pH was lowered to 5.0, especially for the compounds of intermediate lipophilicity (log K(ow)8 2 to 3). This uptake could be ascribed to three processes: (i) accumulation of the cation inside the root cells due to the negative charge on the plasmalemma, as given by the Nernst equation and important only for the polar compounds which have low permeation rates through membranes; (ii) accumulation into the vacuole by ion-trapping, which was the dominant process at high pH for all compounds and at all pH values for the compounds of intermediate lipophilicity; (iii) partitioning on to the root solids, substantial only for the most lipophilic compounds. Translocation to shoots was proportional to uptake by roots, this ratio being independent of external pH for each compound and being optimal for the compounds of intermediate lipophilicity. Such proportionality was also observed in a series of three weaker bases of intermediate lipophilicity, in which compounds of pKa 7.4 to 8.0 were also well taken up and translocated whereas the very weak base 4-ethylaniline (pKa 5-03) was much less so. Tests with quaternised pyridines confirmed that organic cations move only slowly through membranes. The observed behaviour of the amines could be modelled reasonably well assuming that transport within the plant was dominated by movement across membranes of the non-ionised species, and this appeared to be true even for the most lipophilic phenethylamine (log K(ow) 4.67) studied, though its long-distance movement would be as the protonated species.
- Inoue,Chamberlain,Bromilow
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- Derivatives of beta-aminopropionic acid with a fungicidal activity
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Compounds based on derivatives of β-aminopropionic acid having the general formula (I): wherein R1,R2,R3,Ra,K1,W,Z,Ar and Q have the values given in the description. The compounds having general formu
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- Tris(pentafluorophenyl)boron as an Efficient, Air Stable, and Water Tolerant Lewis Acid Catalyst
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Tris(pentafluorophenyl)boron is an efficient, air stable, and water tolerant Lewis acid catalyst for the aldol-type and Michael reactions of silyl enol ethers with carbonyl compounds or other electrophiles (trimethyl orthoformate, dimethal acetal, and chloromethyl methyl ether), the allylation reaction of allylsilanes with aldehydes, and the Diels-Alder reaction of dienes with α,β-unsaturated-aldehydes.A solution of formaldehyde in water is applicable as an electrophile.Also, the aldol-type reaction of ketene silyl acetals with aromatic or aliphatic imines is successfully carried out using the same catalyst.
- Ishihara, Kazuaki,Hanaki, Naoyuki,Funahashi, Miyuki,Miyata, Mayumi,Yamamoto, Hisashi
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p. 1721 - 1730
(2007/10/02)
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