Partial synthesis of boromycin

Desborodesvalinylboromycin has been converted to boromycin via a stereospecific boration, followed by selective acylation with t-Boc-D-valine.     

Partial synthesis of evonoloside

Conclusions The synthesis of evonoloside has been effected from cannogenol and L-rhamnose with a yield of 35%. It has been shown that when a primary alcohol group (at C₁₉) and a secondary axial hydroxy group (at C₃) are present in the aglycone, to introduce the sugar component at C₃ it is desirable first to protect the primary OH group by the partial acetylation of the aglycone.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 1, pp. 20–22, 1969     

Partial synthesis of 4'-demethylepipodophyllotoxin

4′-Demethylepipodophyllotoxin (III) has been synthesized by epimerisation of 4′-demethylpodophyllotoxin (I) via the corresponding chloride II. An improved method for the preparation of III has been developed by selective ether cleavage of the easily available podophyllotoxin (V) using the bromoderivatives VI and VII as intermediates.     

Partial synthesis of octanor-13β-dammarane

The partial synthesis of octanor-13β-dammarane — one of the basic compounds for calculating the effects of substituents in the¹³C NMR spectra of tetracyclic triterpenoids of the dammarane series — has been effected.     

Vobasine-Aspidosperma型双吲哚生物碱的半合成

Aspidosperma型生物碱与Vobasinol在酸性介质中偶合, 得到四个双吲哚生物碱,用^1HNMR与高分辨质谱推定了它们的结构, 各产物对肿瘤细胞生长有显著的抑制作用。     

Partial asymmetric synthesis in the diels-alder reaction

The Diels-Alder condensation of (−)-dimenthyl fumarate with butadiene followed by reduction of the adduct with LiAlH₄, produced (−)-(1R:2R)-4-cyclohexene-trans-1,2-dimethanol in 1–3% optical purity depending on the temperature used to carry out the reaction. However, when AlCl₃, SnCl₄ or TiCl₄ are used to catalyze the reaction then the condensation occurs at much lower temperatures and the product after reduction with LiA1H₄ has the opposite sign and configuration. Furthermore the optical purity of the product ranges from 27–78% depending on reaction conditions. Parameters such as solvent, temperature and catalyst, as they affect asymmetric syntheses, are discussed.     

Partial synthesis of isoeucommiol,a new cyclop entenoid-tetrol

Isoeucommiol 3, a cyclopentenoid-tetrol isomer of eucommiol 1, has been prepared by NaBH₄ reduction of the hemiacetal moiety of aucubigenin 4a. The mechanism of this reduction has been investigated by using NaBD₄.     

Partial resolution through chiral synthesis using a racemic mixture

A racemic mixture of a compound bearing a reactive prochiral center can partially react with a chiral reagent ; diastereomeric products are formed and the starting material is kinetically resolved. The relationships between the relative amounts and the enantiomeric excesses of reaction products and recovered starting material are discussed. Applications are given for asymmetric hydrogenation of racemic AcΔPheAlaOMe catalyzed by a rhodiumdiop complex.