Synthesis and cytotoxicity of novel 14α--(andrographolide-3-subsitutedisoxazole-5-carboxylate) derivatives.

Simple and efficient method was established for the synthesis of a new family of 14α--(andrographolide-3-subsitutedisoxazole-5-carboxylate) derivatives () from naturally occurring andrographolide () by selective esterification with propiolic acid at C-14 using protection and deprotection strategy followed by metal free 1,3-dipolar cycloaddition with aryl nitrile oxides. All the synthesised derivatives were tested for their cytotoxicity against HCT-15, HeLa and DU145 cell lines. Most of the compounds exhibited improved cytotoxic activity compared to the parent molecule andrographolide (), as the compounds , , , , and showed significant cytotoxicity against three cancer cell lines.

Synthesis and cytotoxicity of novel 14α--(1,4-disubstituted-1,2,3-triazolyl) ester derivatives of andrographolide.

A series of novel 14α--(1,4-disubstituted-1,2,3-triazolyl) ester derivatives of andrographolide (-) were synthesized from andrographolide (). For this endeavour, selective esterification at C-14 hydroxyl group of andrographolide () with propiolic acid protection, deprotection strategy followed by 1,4-regioselective [1,3]dipolar cycloaddition of alkyne, azide using Cu(I) catalyzed Click chemistry. All the synthesized derivatives were screened for their cytotoxicity on HCT-15, HeLa and K562 cell lines.

Facial selectivity in the nucleophilic additions of vinylmagnesium bromide to bicyclo[2.2.2]oct-5-en-2-one derivatives.

The levels of diastereoselection attainable by addition of vinylmagnesium bromide to a selection of bicyclo[2.2.2]octenone derivatives 1-6 in the presence of various Lewis acids such as LiBr, CeCl3, TiCl4, ZnBr2, MgBr2, and Et2AlCl have been determined.

Preparation of secolycorines against acetylcholinesterase.

5,6-Secolycorines possessing a 5,6-dihydrophenanthridine skeleton were facilely prepared from lycorine through chemical transformations, mainly including N-alkylation, Hofmann degradation type reaction, reductive cleavage of trichloroethylcarbonyl moiety, and hydrogenation. Several secolycorine derivatives showed potent inhibitory activity against acetylcholinesterase with the IC(50) value at micromolar range and are more potent than galanthamine.

Diels-Alder reactions of 4-triflyloxy-2,6,6-trimethyl-2,4-cyclohexadienone. An expedient methodology for the synthesis of bicyclo[2.2.2]oct-5-en-2-ones and bicyclo[2.2.2]octa-5,7-dien-2-ones.

The synthesis of 4-triflyloxy-2,6,6-trimethyl-2,4-cyclohexadienone (13), bicyclo[2.2.2]octenones 1a-j and 15a-j, and bicyclo[2.

Photochemistry of bicyclo[2.2.2]oct-7-ene-2,5-diones and the corresponding 5-hydroxyimino and 5-methylene derivatives.

Synthesis and photochemistry of several title compounds 1-3 containing multiple chromophoric systems are described. The Diels-Alder reactions of 2,6,6-trimethylcyclohexa-2,4-dienone (5) with acetylenes 6a-d provided the adducts 7a-d, which upon hydrolysis furnished the desired bicyclo[2.2.