Li-Min Wang

Bio: Li-Min Wang is an academic researcher from Zhejiang University. The author has contributed to research in topics: Ionic liquid & Knoevenagel condensation. The author has an hindex of 2, co-authored 3 publications receiving 60 citations.

Green and efficient Knoevenagel condensation catalysed by a DBU based ionic liquid in water

Abstract: An efficient, clean and facile protocol for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds catalysed by task specific ionic liquid 1,8-diazabicyclo[5.4.0]-undec-...

Green and efficient aza-Michael additions of aromatic amines to α,β-unsaturated ketones catalyzed by DBU based task-specific ionic liquids without solvent

Abstract: The DBU (1,8-Diazabicyclo[5.4.0]undec-7-ene) derived task-specific ionic liquids [DBU][Lac] (1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium lactate), [DBU][Ac] (1,8-diazabicyclo[5.4.0]-undec7-en-8-ium acetate) and [DBU][Tfa] (1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium trifluoroacetate) were synthesized. Among the three novel ionic liquids, [DBU][Lac] was found to have the highest catalytic activity for aza-Michael addition of aromatic amines to α,β-unsaturated ketones. The protocol can give good to excellent products yields and has advantages such as readily work-up and good reusability, which makes this method quite attractive.

Silica-bonded 5-n-propyl-octahydro-pyrimido[1,2-a]azepinium chloride (SB-DBU)Cl as a highly efficient, heterogeneous and recyclable silica-supported ionic liquid catalyst for the synthesis of benzo[b]pyran, bis(benzo[b]pyran) and spiro-pyran derivatives

Abstract: The reaction of 3-chloropropyl silica (SilprCl) with 1,8-diazabicyclo[540]undec-7-ene (DBU) in dry acetone affords silica-bonded 5-n-propyl-octahydro-pyrimido[1,2-a]azepinium chloride (SB-DBU)Cl as a new silica-supported ionic liquid catalyst Afterward, (SB-DBU)Cl is used for the efficient synthesis of 4H-benzo[b]pyran derivatives via the one-pot, three-component reaction of carbonyl compounds (cyclohexane-1,3-dione, 5,5-dimethylcyclohexane-1,3-dione or 3-methyl-1-phenyl-2-pyrazolin-5-one) with aromatic aldehydes and alkylmalonates Moreover, some novel bis(benzo[b]pyran)s and a broad range of structurally diverse spiro-pyrans containing oxindole and/or quinoxaline moiety in their structures are synthesized using (SB-DBU)Cl The catalyst is recycled and reused fifteen times with unchanged yield

Novel DABCO Based Ionic Liquids: Green and Efficient Catalysts with Dual Catalytic Roles for Aqueous Knoevenagel Condensation

Abstract: Four novel basic ionic liquids (ILs), based on 1,4-diazobicyclo[2.2.2]octane (DABCO) and 3-chloro-1,2-propanediol, have been introduced as catalysts for Knoevenagel condensation. These catalysts are applicable to a wide range of aromatic/heteroaromatic aldehydes with α-aromatic (heteroaromatic or polyaromatic)-substituted methylene compounds in water at room temperature, and they afford the products in excellent yields within short times. These reactions are operationally simple, and the desired products can be separated directly from the reaction mixture without further purification. A possible reaction mechanism was proposed, and the relevant evidence was given. In addition, the ionic liquids used can be regenerated and recycled several times without significant loss of activity. Furthermore, the novel ILs could be efficiently used in a step of atorvastatin synthesis.