Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• immobilized Candida antarctica lipase B (Novozym 435) was used as a heterogeneous catalyst in the kinetic resolution of the alcohol 22 [30]. Racemization of the unreacted (S)-22 was achieved with acidic zeolite catalysts. Both heterogenous catalysts were coated with ionic liquids for improved stability of the

• lipase in the presence of the acidic chemocatalysts and for reduction of zeolite-catalyzed side reactions [30][31]. The substrates and supercritical CO2 were fed continuously, thus omitting the use of organic solvents for product extraction. An enantiomeric excess of 97% was achieved for the product (R

• resolution of (rac)-1-phenylethanol (22) in supercritical CO2 in a packed-bed reactor loaded with acidic zeolite (A) and Novozym 435 (E) [30]. Synthesis of D-xylulose (28) from D,L-serine (26) and D,L-glyceraldehyde (25) in a continuously operated enzyme membrane reactor. E1: D-Amino acid oxidase; E2

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• mixture of zeolite CP811E-150 as the acid catalyst for the racemization and CALB supported on a SILLP based on bead-type PS-DVB resins [106]. Good results were obtained when the zeolite catalyst was coated with a small amount of an IL. This follows the same trend observed in the case of SILPs

Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes

• Henning Hopf,
• Vitaly Raev and
• Peter G. Jones

Beilstein J. Org. Chem. 2011, 7, 658–667, doi:10.3762/bjoc.7.78

• utilize zeolites as supramolecular hosts for photoreactions [12][13][14]. Internal complexation, or intracrystalline adsorption, occurs by diffusion of the guest into the channels and cavities of the zeolite crystal and is size- and shape-selective. Complexation of organic compounds may reversibly depend

• on temperature. The geometry of zeolite cavities restricts conformation and orientation of included guests and their reaction partners and leads to more selective reactions. In the absence of any low-energy electronic states of the zeolite, photoreaction occurs only with the included guest. The

Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures

• Nadine Schmeling,
• Roman Konietzny,
• Daniel Sieffert,
• Patrick Rölling and
• Claudia Staudt

Beilstein J. Org. Chem. 2010, 6, 789–800, doi:10.3762/bjoc.6.86

• the separation of liquid and gaseous mixtures, in general, porous as well as solution-diffusion membranes can be used. Although porous inorganic membranes, e.g., different zeolite types are characterized by their high thermal and chemical resistance, the application in large scale industrial processes

Zeolite catalyzed solvent- free one-pot synthesis of dihydropyrimidin- 2(1H)-ones – A practical synthesis of monastrol

• Mukund G. Kulkarni,
• Sanjay W. Chavhan,
• Mahadev P. Shinde,
• Dnyaneshwar D. Gaikwad,
• Ajit S. Borhade,
• Attrimuni P. Dhondge,
• Yunnus B. Shaikh,
• Vijay B. Ningdale,
• Mayur P. Desai and
• Deekshaputra R. Birhade

Beilstein J. Org. Chem. 2009, 5, No. 4, doi:10.3762/bjoc.5.4

• Abstract A zeolite-catalyzed, simple, one-pot, solvent-free, cost effective, and environmentally benign process for the synthesis of dihydropyrimidones is described. This reaction is scaleable to multigram scale and the catalyst is recyclable. This methodology has resulted in an efficient synthesis of

• monastrol, a potent inhibitor of kinesin Eg5. Keywords: Biginelli reaction; DHPMs; neat; MCR; zeolite; Introduction The Biginelli reaction is a well-known multicomponent reaction involving a one-pot cyclocondensation of an aldehyde, β-ketoester and urea/thiourea [1][2][3]. Multicomponent reactions (MCRs

• aliphatic aldehydes and thiourea were used low yields of DHPMs were realized. Results and Discussion We herein report a one-pot synthesis of DHPMs using a catalytic amount of zeolite under solvent-free conditions. In our quest to bring about the Biginelli reaction, we attempted the reaction using zeolite