921-48-2

Upstream product

• 319-78-8 isoleucine 
• 4372-15-0 sec-butyl-malonic acid 
• 73-32-5 L-isoleucine 
• 73-32-5 L-isoleucine 

Downstream Products

• 5026-95-9 (+)-(S)-3-methyl-1-pentene 
• 143238-71-5 2'-<6'-((2''S,3''S-2''-chloro-3''-methylpentanoyl)oxy)>naphthyl 4-decyloxybenzoate 
• 228267-65-0 (4R,2'S,3'S)-3-(2'-ethyl-3'-methyl-1'-oxopentyl)-4-benzyl-2-oxazolidinone 
• 210537-40-9 (4S,2'S,3'S)-3-(2'-ethyl-3'-methyl-1'-oxopentyl)-4-benzyl-2-oxazolidinone 
• 228267-64-9 (4R,3'S)-3-(3'-methyl-1'-oxopentyl)-4-benzyl-2-oxazolidinone 
• 133729-84-7 (4S,3'S)-3-(3'-methyl-1'-oxopentyl)-4-benzyl-2-oxazolidinone 
• 1730-92-3 (3S)-methylvaleric acid 
• 516479-93-9 4-[⁽¹⁾-chloro-⁽²⁾-methylbutyl carboxy]-4'-biphenylcarboxyphenylferrocene 

Relevant academic research and scientific papers

Forming Stereogenic Centers in Acyclic Systems from Alkynes

The combined carbometalation/zinc homologation followed by reactions with α-heterosubstituted aldehydes and imines proceed through a chair-like transition structure with the substituent of the incoming aldehyde residue preferentially occupying a pseudo-axial position to avoid the two gauche interactions. The heteroatom in the axial position produces a chelated intermediate (and not a Cornforth-Evans transition structure for α-chloro aldehydes and imines) leading to a face differentiation in the allylation reaction. This method provides access to functionalized products in which three new carbon-carbon bonds and two to three stereogenic centers, including a quaternary one, were created in acyclic systems in a single-pot operation from simple alkynes. All-carbon quaternary stereocenter: The combined carbometalation/zinc homologation of alkynes followed by reactions with α-heterosubstituted aldehydes and imines provides access to functionalized acyclic adducts. These adducts obtained in a single-pot reaction have three new carbon-carbon bonds and two to three stereogenic centers, including a quaternary carbon stereocenter.

Synthesis and characterization of ferroelectric liquid crystalline siloxanes containing 4-hydroxyphenyl(2S,3S)-2-chloro-3-methylvalerate

New series of organosiloxane ferroelectric liquid crystalline materials have been synthesized, and their mesomorphic and physical properties have been characterized. These new series contain bis-siloxane or tris-siloxane unit attached to the flexible alkyl chain end of (2S,3S)-2-chloro-3-methylvalerate. The siloxane molecule induction is helpful to the chiral smectic C (S C) formation and chiral SC* stabilization, and it simultaneously causes the liquid crystal temperature range of chiral S C* to be broader. The siloxane member is helpful in reducing the smectic C (SC) transation shift temperature, and the molecule containing tris-siloxane units shows better effect than the bis-siloxane one. The synthesis and characterization of the new FLCs materials which exhibit SC* phase at room temperature and higher spontaneous polarization are presented.

Stereoselective synthesis of chiral 4-(1-Chloroalkyl)-β-lactams starting from amino acids and their transformation into functionalized chiral azetidines and pyrrolidines

Chiral short-chain α-chloroaldehydes were prepared starting from enantiomerically pure amino acids in a three-step approach, thus providing a practical synthetic alternative for known organocatalytic α-chlorination procedures. The latter aldehydes proved

Liquid crystal dimers derived from naturally occurring chiral moieties: synthesis and characterization

Naturally occurring cholesterol and α-chloroalkanoyl units derived from natural α-amino acids (l-valine, l-leucine, and l-isoleucine) have been utilized to prepare three different series of nonsymmetric liquid crystal dimers. Tolane (diphenylacetylene), w

Design of siloxane liquid crystals forming a de vries SmA* phase

We designed and synthesized new SmA* liquid crystals with different molecular architectures based on the chiral mesogen MR11, which was unsubstituted, or attached at one end and at both ends of a trisiloxane segment in the monosubstituted MSi3-MR11 and disubstituted DSi3-MR11 siloxanes, respectively. We studied the critical divergence of the magnetic susceptibility by measurements of the induced tilt angle θind at the SmA*-SmC* transition. While all three SmA* liquid crystals presented a de Vries character, this was quite distinctive for DSi3-MR11 for which the critical exponent γ = 1.87 was maximal. X-ray diffraction experiments confirmed that the SmA*-SmC* transition occurred with essentially no layer shrinkage.

Kinetic resolution of chiral α-olefins using optically active ansa-zirconocene polymerization catalysts

A series of enantiopure C1-symmetric metallocenes, {(SiMe 2)2[η5-C5H(CHMe 2)2][η5-C5H2((S) CHMeCMe3)]}ZrCl2, (S)-2, {(SiMe2) 2[η5-C5H(CHEt2) 2][η5-C5H2((S)-CHMeCMe 3)]}ZrCl2, (S)-6, and {(SiMe2) 2[η5-C5HCy2][η5- C5H2((S)-CHMeCMe3)]}ZrCl2), (S)-7 (Cy = cyclohexyl), zirconocene dichlorides that have an enantiopure methylneopentyl substituent on the "upper" cyclopentadienyl ligand, and diastereomerically pure precatalysts, {(SiMe2) 2[η5-C5H((S)-CHMeCy)(CHMe 2)][η5-C5H3]}ZrCl2, (S)-8a and (S)-8b, which have an enantiopure, 1-cyclohexylethyl substituent on the "lower" cyclopentadienyl ligand, has been synthesized for use in the polymerization of chiral α-olefins. When activated with methylaluminoxane, these metallocenes show unprecedented activity for the polymerization of bulky racemic monomers bearing substitution at the 3- and/or 4-positions. Due to the optically pure nature of these single site catalysts, they effect kinetic resolution of racemic monomers: the polymeric product is enriched with the faster reacting enantiomer, while recovered monomer is enriched with the slower reacting enantiomer. The two components are easily separated. For most olefins surveyed, a partial kinetic resolution was achieved (s = kfaster/kslower ≈ 2), but, in one case, the polymerization of 3,4-dimethyl-1-pentene, high levels of separation were obtained (s > 15). 13C NMR spectroscopy of poly (3-methyl-1-pentene) produced with (S)-2 indicates that the polymers are highly isotactic materials. X-ray crystal structure determinations for (S)-2, {(SiMe2)2[η 5-C5H(CHMe2)2][η5- C5H2((S)-CHMeCMe3)]}Zr(SC6H 5)2, (S)-6, and (S)-7 have been used in combination with molecular mechanics calculations to examine the prevailing steric interactions expected in the diastereomeric transition states for propagation during polymerization. Precatalysts (S)-8a and (S)-8b are less selective polymerization catalysts for the kinetic resolution of 3-methyl-1-pentene than are (S)-2, (S)-6, and (S)-7.

Thermal behaviour and mesophase structure of cyclic oligosiloxanes with chiral mesogenic groups

Chiral, smectogenic pendant groups have been covalently attached to cyclic oligosiloxanes by hydrosilylation. Differential scanning calorimetry, optical polarising microscopy, and X-ray diffraction measurements reveal liquid crystalline properties for all

Amelioration of neurological disorders by the administration of (2R),(3S), and/or (2S),3(S) stereoisomers of valnoctamide

The present invention generally relates to the individual stereoisomers of the drug valnoctamide (a mixture of four stereoisomer kinds, VCD-valmethamide or 2-ethyl-3-methyl pentanamide) useful in treatment of neurological and psychotic disorders such as d

Absolute configuration of the four stereoisomers of valnoctamide (2- ethyl-3-methyl valeramide), a potentially new stereospecific antiepileptic and CNS drug

Valnoctamide (2-ethyl-3-methyl valeramide, Nirvanil, VCD), a mild tranquilizer endowed with anticonvulsant properties, exhibits diastereoselective and enantioselective pharmacokinetics in healthy subjects and epileptic patients. The purpose of this paper

Synthesis of new polymerizable liquid-crystal molecules

On the way to get a comparison between different side-chain liquid-crystal polymers bearing the same lateral mesogenic group, in order to show the influence of the nature of the polymer backbone on their thermal behaviors, we present here the synthesis of