Stereoselective synthesis of (<i style="">2R</i>, <i style="">3S</i>, <i style="">22R</i>, <i style="">23E</i>)-6, 6-ethylenedioxy-22-hydroxy- 2, 3- isopropylidenedioxy-24-methyl-5<img src='/image/spc_char/alpha.gif' border=0>-cholest-23-ene: An intermediate for the synthesis of castasterone, dolichosterone and brassinolide

611-614Wittig reaction on (2R, 3S)-2,3-isopropylidenedioxy-6,6-ethylene-dioxy-5 -pregnane-(20S)-20-carbaldehyde 6, furnishes stereoselcctively an 22(E)- ,-unsaturated ketone 7, which on reaction with methyllithium followed by 1,3-carbonyl trans­position and stereoselective reduction with DIBAL-H affords the title compound 10, an intermediate for castasterone, dolicho­sterone and brassinolide

An efficient synthesis of (2, 3 and 22, 23)-diepoxybrassinosteroids and their plant growth promoting activity^†

955-959A highly efficient synthesis of (2,3 and 22,23)-diepoxybrassinosteroids using molecular oxygen, benzaldehyde and transition metal oxides as catalysts has been achieved and they showed moderate plant growth promoting activity

Amino functionalized novel cholic acid derivatives induce HIV-1 replication and syncytia formation in T cells

Synthesis of C-11 azido/amino functionalized cholic acid derivatives has been achieved in excellent yields. Contrary to the previous prediction of analogous compounds to be HIV-1 protease inhibitors, in the present study these novel cholic acid derivatives induced host cell fusion during the progress of HIV-1 infection and produced multinucleated giant cells. This is the first report of syncytia induction and enhancement of viral replication in HIV-1 infected T cells by cholic acid derivatives

Synthesis of 11β-(4-dimethylaminophenyl)-17β-hydroxy-17α-(3-methyl-1-butynyl)-4,9-estradien-3-one and 11β-(4-acetophenyl)-17β-hydroxy-17α-(3-methyl-1-butynyl)-4,9-estradien-3-one: two new analogs of mifepristone (RU-486)

From the structure activity relationship, two new analogs, 2 and 3, of the potent progesterone antagonist mifepristone 1 have been designed. The syntheses of these two analogs have been achieved in eleven steps through modified synthetic sequences and improved procedures starting from (+)-estrone. In comparison with mifepristone 1, the relative binding affinities of compound 2 for the progesterone receptor was found to be more, whereas that of compound 3 was less

Synthesis and biological evaluation of bile acid dimers linked with 1,2,3-triazole and bis-β-lactam

We report herein the synthesis and biological evaluation of bile acid dimers 11-18 linked through 1,2,3-triazole and bis-β-lactam. The dimers 11-18 were synthesized using 1,3-dipolar cycloaddition reaction of diazido bis-β-lactams 3, 4 and terminal alkynes 7-10 derived from cholic acid/deoxycholic acid in the presence of Cu(I) catalyst (click chemistry). These novel molecules were evaluated in vitro for their antifungal and antibacterial activity. Most of the compounds exhibited significant antifungal as well as antibacterial activity against all the tested fungal and bacterial strains. Moreover, their in vitro cytotoxicities towards HEK-293 and MCF-7cells were also established

Synthesis of chimeric tetrapeptide-linked cholic acid derivatives: impending synergistic agents

Tetrapeptides derived from glycine and β-alanine were hooked at the C-3β position of the modified cholic acid to realize novel linear tetrapeptide-linked cholic acid derivatives. All the synthesized compounds were tested against a wide variety of microorganisms (Gram-negative bacteria, Gram-positive bacteria and fungi) and their cytotoxicity was evaluated against human embryonic kidney (HEK293) and human mammary adenocarcinoma (MCF-7) cell lines. While relatively inactive by themselves, these compounds interact synergistically with antibiotics such as fluconazole and erythromycin to inhibit growth of fungi and bacteria, respectively, at 1-24 μg/mL. The synergistic effect shown by our novel compounds is due to their inherent amphiphilicity. The fractional inhibitory concentrations reported are comparable to those reported for Polymyxin B derivatives