933-35-7Relevant academic research and scientific papers
Preparation and reactions of optically active cyanohydrins derived from 4-chlorobenzaldehyde, cyclohexanone and 2-methylcyclohexanone using the (R) hydroxynitrile lyase from Prunus amygdalus
Yosef,Elmasry,Ismael, Eman H. I.,Mahran
, p. 745 - 755 (2013/05/21)
CYANURATION of 4-chlorobenzaldehyde (1), cyclohexanone (2a) and 2-methylcyclo-hexanone (2b) yielded the racemic 2-hydroxy-2-(4-chlorophenyl) ethanenitrile (R,S)-3, cyclohexanone cyanohydrin 21a and (R,S)-2- methylcyclohexanone cyanohydrin (R,S)-21b. The same reaction can be completed by using acetone cyanohydrin (4) as a transcyanating agent. The optically active cyanohydrins (R)-3 and (R)-21b could be respectively obtained by hydrocyanation of 1 and 2b using (R)-hydroxynitrile lyase (R) PaHNL [EC 4.1.2.10] from almonds (Prunus amygdalus) as a chiral catalyst. Cyanohydrins 3 and 21 in their racemic and optically active forms undergo a number of transformations which involve either the hydroxyl group or the cyanide function. Moreover, derivatization of 3 and 21b with (S)-Naproxen chloride (S)-7 gave the respective diastereoisomers 8 and 22b. The optical activities of (R)-3 and 21b as well as their derivatives were recorded. The postulated structures of the new products were supported with compatible elementary and spectroscopic (IR, 1H NMR, 13C NMR, MS and X-ray crystallography) analyses. The antitumor activity of some selected racemic new products and their respective optically active analogues were undertaken. The structure-activity relationship (SAR) was also discussed.
Robust and efficient, yet uncatalyzed, synthesis of trialkylsilyl-protected cyanohydrins from ketones
Cabirol, Fabien L.,Lim, Angela E. C.,Hanefeld, Ulf,Sheldon, Roger A.,Lyapkalo, Ilya M.
, p. 2446 - 2449 (2008/09/19)
(Chemical Equation Presented) High-yielding cyanosilylation of ketones with NaCN and various chlorotrialkylsilanes in DMSO proceeds smoothly without catalysis to give silyl-protected ketone cyanohydrins. The unique role of DMSO consists in rendering naked
Highly efficient trialkylsilylcyanation of aldehydes, ketones and imines catalyzed by a nucleophilic N-heterocyclic carbene
Kano, Taichi,Sasaki, Kouji,Konishi, Teppei,Mii, Haruka,Maruoka, Keiji
, p. 4615 - 4618 (2007/10/03)
The synthetic utility of N-heterocyclic carbenes was demonstrated by the trialkylsilylcyanation of aldehydes, ketones and imines. In the presence of a catalytic amount of 3a, the reactions with Me3SiCN proceeded smoothly to give the corresponding cyanohydrin trimethylsilyl ethers or amino nitrile derivatives in good to excellent yields.
Hydroxynitrile lyase-catalyzed addition of HCN to 2- and 3-substituted cyclohexanones
Kobler, Christoph,Bohrer, Anja,Effenberger, Franz
, p. 10397 - 10410 (2007/10/03)
The addition of HCN to monosubstituted cyclohexanones yielding cyanohydrins is strongly catalyzed by hydroxynitrile lyases (HNLs). With PaHNL from bitter almonds, the addition to 2-alkyl cyclohexanones 1b-g is highly (R)-selective, whereas the methyl compound 1a reacts (S)-selectively. With MeHNL from cassava, all 2-alkyl derivatives 1 react (S)-selectively. The catalytic activity of both PaHNL and MeHNL decreases with increasing size of the substituent in substrates 1. The diastereoselectivity of HCN additions to 2-alkoxy cyclohexanones 4 and 3-substituted cyclohexanones 6, however, is only moderate. The absolute configuration of the synthesized cyanohydrins was determined by X-ray crystallography of O-p-bromobenzoyl derivatives. Graphical Abstract.
Synthesis of All Eight Stereoisomers of the Germination Stimulant Sorgolactone
Sugimoto, Yukihiro,Wigchert, Suzanne C. M.,Thuring, Jan Willem J. F.,Zwanenburg, Binne
, p. 1259 - 1267 (2007/10/03)
The naturally occurring sesquiterpene sorgolactone (2) belongs to the class of "strigolactones", which are highly potent germination stimulants for seeds of the parasitic weeds Striga and Orobanche. The aim of the present work was to synthesize all eight
Lactone Formation in Superacidic Media
Carr, Graham,Whittaker, David
, p. 1877 - 1880 (2007/10/02)
The reaction of substituted 1-hydroxycyclohexanecarboxylic acids in fluorosulphuric acid has been studied.Cyclisation takes place around 0 deg C, accompanied by rearrangement in appropriate cases, yielding the thermodynamically stable lactone or mixture of lactones.An unexpected feature of these reactions is that the carboxy-substituted cyclohexyl carbocation does not undergo ring contraction, unlike the unsubstituted cyclohexyl carbocation, although the cycloheptyl system contracts to cyclohexyl.We suggest that the cyclohexyl carbocation is strongly stabilised by carboxyl substitution, as a result of through-space interaction between the carboxyl oxygen atom and the carbocation centre.
DIENAMINES AS DIELS-ALDER DIENES. AN EFFICIENT CYCLOHEXANNULATION SEQUENCE.
Snowden, Roger L.,Wuest, Manfred
, p. 699 - 702 (2007/10/02)
An efficient cyclohexannulation sequence is described whose key step involves a Diels-Alder reaction between an (E)-dienamine and methyl acrylate.
