Cyanoethylation of alcohol

Kumbhar et al. found that Mg/Al-COs LDHs heated in N2 up to 823 K are highly active and selective catalysts for the Uquid phase MPV reduction of carbonyl compounds using 2-propanol as the hydrogen donor [46] the catalysts can also readily be regenerated. The same LDH precursor after thermal decarbonation and rehydration has been used in the cyanoethylation of alcohols [54], showing high activity and air stabihty (in contrast to other soUd base catalysts). 

C. Carbon- Oxygen Bond Formation Reactions C.l. Cyanoethylation of Alcohols... 

Cyanoethylation of acrylonitrile with monohydric alcohols gives alkoxypropio-nitriles (Scheme 25). These nitriles can be converted into various types of carboxylic acids by hydrolysis, and they can be hydrogenated to give amines. Therefore, cyanoethylation of alcohols is an important reaction for the synthesis of drug intermediates and organic compounds of industrial interest. 

According to the Lewis theory, alkaline earth metal hydroxides are weaker bases than their oxides, the order of the strength of the basic sites being Ba(OH)2> SrO(OH)2 > Ca(OH)2 > Mg(OH)2. The hydroxides have been used recently as solid catalysts for organic transformations, such as the conjugate addition of methanol to a, S-unsaturated carbonyl compounds (12), cyanoethylation of alcohols (163,164), and transesterification reactions (166,167,171,172) which are described above. The extensive work of Sinisterra et al. (282) on the number and nature of sites and on the catalytic activity of the most basic alkali metal hydroxide, Ba(OH)2, is emphasized. It was found that commercial barium hydroxide octahydrate can be converted into... 

Anion exchange resins of the quaternary ammonium hydroxide type (e.g., De-Acidite FF, IRA-400 or Dowex I) are strong bases and are useful catalysts for the cyanoethylation of alcohols and possibly of other active hydrogen compounds. 

Kabashima, H. and Hattori, H. Cyanoethylation of alcohols over solid base catalysts, Catal. Today, 1998, 44, 277-283. 

Choudary, B. M., Kantam, M. L. and Kavita, B. Mg-Al-O-Bu-t-Hydrotalcite a mild and ecofriendly catalyst for the cyanoethylation of alcohols and thiols. Green Chem., 1999,1, 289-292. 

Kumbhar, P. S., Sanchez-Valente, J. and Figueras, F. (1998). Modified Mg-Al hydrotalcite a highly active heterogeneous base catalyst for cyanoethylation of alcohols../ Chem. Soc., Chem. Commun., 1091. 

Used for the cyanoethylation of alcohols, mercaptans, aldehydes, ketones, malonic ester, nitromethane, broraoform, etc. ... 

In this group of reactions we can cite cyanoethylation of alcohols such as methanol, ethanol and 2-propanol with acrylonitrile [261] (Figure 17a) and conjugate addition of methanol to 3-buten-2-one (Figure 17b) [17.66]. 

Reconstructed Hydrotalcite. When calcined hydrotalcite (Mg0-Al203) is rehydrated in water or in flowing nitrogen saturated with water, hydrotalcite structure is reconstructed. This phenomenon is called memory effect. The reconstructed materials contain OH in the interlayers. The reconstructed materials are very useful catalysts for aldol condensation, Knoevenagel condensation, Michel addition, and cyanoethylation of alcohols (22-24). The OH ions in the interlayer are believed to be the active sites for these reactions. 

Kumbhar et al. found that calcined and rehydrated MgAl-COs-LDH is a highly active, reusable and air stable catalyst for the cyanoethylation of primary and secondary alcohols with very high conversion and selectivity at 50°C (574). Chou-dary et al. reported that MgAl-tetra-butanoate-LDH can be directly used as catalyst in the cyanoethylation of alcohols and thiols with very high conversion and selectivity at room temperature (575). 

Astle and Zaslowsky utilized a variety of anion-exchange resins to effect Knoevenagel condensations, aldol condensations, and cyanoethylation of alcohols. Knoevenagel condensation... 

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