Solvent-Free Hydrolysis

Type of reaction hydrolysis Reaction condition solid-state 

Compound la (100 mg, 0.47 mmol) or lb (100 mg, 0.39 mmol) was placed on a glass frit and moist air was sucked through by an aspirator for 2 h. The slightly wettish crystals were dried in a high vacuum and consisted of pure 2 according to XH NMR analysis. 

The reaction is reversible If an excess of HX gas was applied to 2 the pure compound la or lb was obtained. 

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Solvent-Free Hydrolysis under Microwave Irradiation... 

Solvent-free hydrolysis of the warfare agents VX (<9-ethyl S -2-(diiso-propylamino)ethyl methylphosphonothioate) (410), GB (O-isopropyl methylphosphonofluoridate or sarin) (414), in the presence of various alumina-supported fluoride reagents such as KF/AI2O3, AgF/KF/Al203 and KF/AI2O3 has been described by Zafrani and co-workers. " While (414) reacted instantaneously with these solid supports to yield the non-toxic product z-propyl methylphosphonic acid (415), the less reactive (410) gave... 

Condensation ofDianhydrides with Diamines. The preparation of polyetherknides by the reaction of a diamine with a dianhydride has advantages over nitro-displacement polymerization sodium nitrite is not a by-product and thus does not have to be removed from the polymer, and a dipolar aprotic solvent is not required, which makes solvent-free melt polymerization a possibiUty. Aromatic dianhydride monomers (8) can be prepared from A/-substituted rutrophthalimides by a three-step sequence that utilizes the nitro-displacement reaction in the first step, followed by hydrolysis and then ring closure. For the 4-nitro compounds, the procedure is as follows. 

The groups of Loupy and Jun have presented a chelation-assisted rhodium(I)-cata-lyzed ortho-alkylation of aromatic imines with alkenes (Scheme 6.57) [119]. The use of 2 mol% of Wilkinson s catalyst, RhCl(PPh3)3, and 5 equivalents of the corresponding alkene under solvent-free conditions proved to be optimal, providing the desired ortho-alkylated ketones in high yields after acidic hydrolysis. Somewhat lower yields were obtained when the imine preparation and the ortho-alkylation were realized in a one-pot procedure. 

Apart from the classic preparation of simple germanes Ge H2n+2 (where n = 2-5) from the hydrolysis of Mg2Ge201, the following solvent-free reaction202 gives satisfactory yields of digermanes ... 

He, Y, Johansson, M. and Sterner, O. (2004) Mild microwave-assisted hydrolysis of acetals under solvent-free conditions. Synth. Commun., 34 (22), 4153-4158. 

However, for some specific reactions, solvent-free systems are preferred because of their higher yields. The main area of development should be related to the hydrolysis of glycerides, transesterification, esterification and inter-esterification reactions. As lipases have high and stable activity in SC CO2 (even at the high temperature) an intensive development is expected. 

A solvent-free photooxygenation of 5-methoxyoxazoles 169 embedded in porphirin-loaded polystyrene beaded as solid support resulted in 3//-1,2,4-dioxa/olcs 170 as sole products in good yields. Stereoselective synthesis of a-amino carboxylic acids derivatives 171 was developed by acid catalyzed hydrolysis of compounds 170 (Scheme 45) <2005JCR422>. 

Patel, M.T., Nagarajan, R., Kilara, A. 1996. Hydrolysis of milk fat by lipase in solvent-free phospholipid reverse micellar media. J. Food Sci. 61, 33-38. 

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