Preparation and reactions of optically active cyanohydrins using the (R)-hydroxynitrile lyase from Prunus amygdalus

Abstract

Cyanuration of 2-naphthaldehyde (1) and 5-methyl-2-furaldehyde (2) yielded the racemic 2-hydroxy-2-(β-naphthyl)ethanenitrile (R,S)-3 and 2-hydroxy-2-(5-methyl-2-furyl)ethanenitrile (R,S)-5, respectively. The same reaction can be completed by using acetone cyanohydrin (4) as a transcyanating agent. The optically active (R)-3 and (S)-5 could be respectively obtained by hydrocyanation of 1 and 2 using (R)-hydroxynitrile lyase (R)-PaHNL [EC 4.1.2.10] from almonds (Prunus amygdalus) as a chiral catalyst. Cyanohydrins 3 and 5 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 5 with (S)-Naproxen ® chloride (S)-14 gave the respective diastereoisomers. The optical activity of (R)-3 and (S)-5 as well as their derivatives were recorded. The postulated structures for the new products were supported with compatible elementary and spectroscopic (IR, 1 H NMR, 13 C NMR, MS, and single crystal X-Ray crystallography) analyses. The antimicrobial activity of some selected racemic new products and their respective optically active analogues were also undertaken.

Opposite effects of a singlet oxygen quencher on photochemical degradation of dicyano-substituted poly(phenylenevinylenes) with different side chains

“…The new CN peak, which is not from oxo-acetonitrile as no peak rises in the carbonyl region, is assigned to product Q in Scheme 2, which has two cyano-containing moieties: cyanohydrin and phenylacetonitrile. The peak position is close to those of naththalenyl cyanohydrin (2248 cm -1 ) 21 and phenylacetonitrile (2252 cm -1 ). From the relative peak intensities of vinylenyl cyano (2216 cm -1 ) and the cyano groups of M (2243 cm -1 ) (in the inset of Figure 6), the amount of decomposed vinylene units is estimated to be 26% (or on average 4 units per polymer chain) at 5 minutes.…”

Preparation and Reactions of Certain Racemic and Optically Active Cyanohydrins Derived from 2-Chlorobenzaldehyde, 4-Fluorobenzaldehyde, Benzo[d][1,3]-dioxole-5-carbaldehyde and 2,3-Dihydrobenzo[b][1,4]dioxine-6-carbaldehyde. Antimicrobial and in vitro Antitumor Evaluation of the Products

“…In general, both racemic and optically active cyanohydrins undergo a number of transformat ions which involve the hydroxy l and/or cyanide functions in their molecules [1,2,4,5,12].…”

“…Racemic and optically active cyanohydrins belong to ubiquitous family and they have proven to be valuable building blocks for many synthetic purposes [1][2][3][4][5][6][7][8][9]. They are essentially p repared by hydrocyanation of the appropriate aldehyde or ketone [1-3, 5, 6].…”

“…They are essentially p repared by hydrocyanation of the appropriate aldehyde or ketone [1-3, 5, 6]. In particular, optically active cyanohydrins are expedient starting materials for the d irect synthesis of different classes of biologically interesting principles such as −hydro xy carbo xy lic acids [1,4,5,10,11] and 2-amino alcohols [10,[12][13][14]. The enantioselective preparation of optically pure cyanohydrins is catalytically developed by making use of cyclic dipeptides [9], nanocrystalline magnesium o xide [15] and various chiral co mplexes of titaniu m [16], alu minu m [17] and boron [18].…”

“…Besides, it can be enzymatically cataly zed by means of hydro xynitrile lyases (o xynitrilases) extracted fro m plant sources [2,4,19]. This approach is rather decisive, clean and cheap [5,[20][21][22][23]. The increasing interest in synthesizing optically pure compounds is due to the well established correlation between the biological act ivity and stereochemical aspects [24][25][26][27].…”