Synthesis of propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4-di-O-(2s-methylbutyryl)-α-L-rhamnopyranosyl]-(1→2)=(3-O-acetyl-β-D-glucopyranosyl)-(1→2)-βp-D-fucopyranoside,the tetrasaccharide moiety of Tricolorin A

Propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4di-O-(2s-methylbutyryl)-α-L-rhamnopyranosyl]-(1→2)-(3-O-acetyl-β-glucopyranosyl)-(1→2)-β-D-fucopyranoside (1), the tetrasaccharide moiety of Ricolorin A, was synthesized in total 23 steps with a longest linear sequence of 10 steps, and overall yield of 3.7% from D-Glucose. The isomerization of the dioxolane-type benzylidene in the prance of NIS/AgOTf was observed. Tetrasaccharide 1 exhibited no activity against the cultured P388 cell as Tricolorin A did.     

Synthesis of Diphenyl α-（Dipropoxyphosphoramido）alkyl-phosphonates

A convenient method has been developed for the synthesis of diphenyl α-（dipropoxyphosphoramido）alkyl- phosphonates under mild conditions, namely the reaction of dipropyl phosphoramidate （1） with a para（un）substituted benzaldehyde or cyclicketone （2） and triphenyl phosphite （3） by a one-pot procedure with the aid of acetyl chloride.     

Synthesis of poly(γ-methoxypropylmethylsilylene) and poly(γ-methoxypropylmethylsilylene-co-di-n-hexylsilylene)

The synthesis of γ;-methoxypropylmethyldichlorosilane, and its subsequent polymerization and copolymerization with di;-n;-hexyldichlorosilane through the reductive coupling with sodium has been accomplished. The resulting polymers contain methyl ether side groups that allow further synthetic transformations on the polysilane backbone. For poly (γ;-methoxypropylmethylsilylene) these groups impart solubility characteristics different than typical alkyl and aryl substituted polysilanes. These new polymers and copolymers have been characterized by GPC and ¹H-, ¹³C-, and ²⁹Si-NMR. © 1994 John Wiley & Sons, Inc.     

Synthesis of Poly(α‐alkyl β,L‐aspartate)s by Transesterification

A new procedure for the preparation of poly(α‐alkyl β,L ‐aspartate)s based on the transesterification of polyα‐benzyl β,L ‐aspartate) with alcohols in the presence of titanium tetrabutoxide is described. The reaction proceeded to almost total conversion without substantial racemization or imidation. Thermal properties of the resulting polymers were comparable to those of their homologues obtained by anionic ring‐opening polymerization of β‐lactams and their thermal stability is even higher.     

Pyrrolidine and α-methylene-α-lactam from the cyclization of α-(alkylaminoethyl)acrylate: Synthesis of aza-sarkomycins

Diene readily adds primary amines to give which can cyclize either in a Michael addition fashion or via a displacement reaction to give, respectively, pyrrolidine or methylene lactam which further isomerizes to under the employed reaction conditions. Compound can be obtained as the sole product from the reaction of diene precursor with amines followed by vacuum pyrolysis.     

Synthesis of 17β-hydroxy-1′-H-5α-androst-2-eno[3,2-b]pyrrole and 17β-hydroxy-1′-H-5α-androst-3-eno[3,4-b]pyrrole from O-(2-hydroxyethyl)ketoxime precursors

Pyrrolosteroids such as 17β-hydroxy-1′-H-5α-androst-2-eno[3,2-b]pyrrole ( 1 ) and the novel 17β-hydroxy-1′-H-5α-androst-3-eno[3,4-b]pyrrole ( 12 ) can be synthesized from the corresponding O-(2-hydroxyethyl)ketoxime precursors. In the case of 1 , yields compare favourably with previously reported literature methods.     

Synthesis of novel α,α′,β-trisubstituted β-lactones

A concise and efficient synthesis of α,α′,β-trisubstituted β-lactones is presented. These novel lactones are easily obtained in five steps and will be dedicated to anionic ring opening polymerization.     

Synthesis of α,α′‐Bis(Substituted Benzylidene)Cycloalkanones Catalyzed by Amino‐Functionalized Ionic Liquid

Condensation of aromatic aldehydes with cyclopentanone and cyclohexanone using amino‐functionalized ionic liquid, 1‐aminoethyl‐3‐methyl tetrafluoroborate as solvent and catalyst was successfully performed for preparation of α,α′‐bis(substituted benzylidene)cycloalkanones. The catalyst can be recovered and reused for at least three times without apparently lose of activity. The process is simple, environmentally benign and proceeds in excellent yields.