Milind D. Nikalje

Enantioselective synthesis of (R)-(−)-baclofen via Ru(II)–BINAP catalyzed asymmetric hydrogenation

Abstract A short and efficient enantioselective synthesis of ( R )-(−)-baclofen, a selective GABA B agonist has been described with an overall yield of 26% and 90% ee. Ru(II)–( S )-BINAP catalyzed asymmetric hydrogenations of CC and CO groups constitute the key steps in introducing stereogenic centers into the molecule.

Fabrication of chitosan microspheres using vanillin/TPP dual crosslinkers for protein antigens encapsulation.

Microspheres were prepared from water soluble chitosan using dual vanillin/TPP crosslinkers. Placebo (C1), Bovine serum albumin (BSA) (C2), monovalent tetanus toxoid (TT) (C3) and divalent tetanus (TT) and diphtheria toxoids (DT) (C4) encapsulated microspheres were studied in terms of size (1-4 μm), encapsulation efficiency (75-80%), swelling and mucoadhesion (56-68%). FT-IR, TGA, XRD and SEM characterization of microspheres suggested specific interaction, more thermal stability, amorphous nature and rough surfaces of encapsulated microspheres. EDS confirmed the co-crosslinking and ninhydrin tests were showing higher crosslinking density. Zeta potential was 47.7 to 66.2 +mV indicating the potential stability of the colloidal system. Equilibrium adsorption isotherms described encapsulated microspheres followed the Langmuir isotherm model, suggesting monolayer adsorption of the mucin on microspheres. In-vitro release studies up to four weeks indicated zero order kinetics and obeyed swelling-controlled super case II transport release mechanism. Thus, the present study could be helpful in developing the multivalent oral vaccine.

Simple and Efficient Synthesis of (S)-Dapoxetine

Abstract A refinement in the synthetic strategy for (S)-dapoxetine 1 is described. The key features of synthetic strategy include (a) a Sharpless asymmetric epoxidation reaction and regioselective reductive ring opening of a 2,3-epoxy alcohol to elaborate the hydroxy-bearing stereogenic center at benzylic position; (b) regioselective functionalization of 1-naphthol and amine functionality through Mitsunobu procedures; and (c) Eschweiler–Clarke reductive methylation condition to access the target molecule. GRAPHICAL ABSTRACT

Regioselective synthesis of a vitamin K3 based dihydrobenzophenazine derivative: its novel crystal structure and DFT studies

A novel acid catalyzed regioselective Michael addition of o-phenylenediamine to vitamin K3 has been carried out to synthesize a dihydrobenzophenazine derivative viz. 6a-methyl-6a,7-dihydrobenzo[α]phenazin-5(6H)-one (1). The compound has been characterized using the single crystal X-ray diffraction and density functional theory.

Asymmetric synthesis of propranolol, naftopidil and (R)-monobutyrin using a glycerol desymmetrization strategy

Este trabalho descreve uma abordagem para dessimetrizacao de glicerol utilizando canforsulfonamida disponivel como material de partida. A estrategia para sintese assimetrica de (R)/(S)-propranolol, (R)/(S)-naftopidila e (R)-monobutirina com formacao de espirocetal por dessimetrizacao foi empregada e a reacao de Mitsunobu foi utilizada para a formacao de epoxido e eter. Esterificacao de Steglich e CAN (nitrato de cerio amonia) mediaram a desprotecao de cetal como etapas chave na sintese. A abertura regioseletetiva do anel do epoxido forneceu a molecula desejada com bom rendimento e pureza otica. Herein, an approach for desymmetrization of glycerol by using a readily available camphorsulfonamide as a starting material is described. The strategy for asymmetric synthesis of (R)/(S)-propranolol, (R)/(S)-naftopidil and (R)-monobutyrin with spiroketal formation by desymmetrization was employed and Mitsunobu reaction was used for epoxide and ether formation. Steglich esterification and CAN (cerium ammonium nitrate) mediated ketal deprotection, were key steps in the synthesis. Regioselective ring opening of epoxide gave desired molecule with good overall yield and optical purity.