Synthesis of dibenzo[a,d]cycloheptanoids via aryne insertion into 2-arylidene-1,3-indandiones.

A novel and unexpected aryne insertion cascade reaction on 2-arylidene-1,3-indandiones via conjugate addition of fluoride followed by formal C-C insertion is developed to afford dibenzo[a,d]cycloheptanoid derivatives in good yields with a single isomer. This reaction represents a rare instance of cyclic enone C-C bond insertion (acyl-alkenylation) in aryne chemistry. Interestingly, 2-arylidene-1,3-indandiones bearing electron rich functional groups provided dibenz[a,c]anthracene-9,14-dione derivatives via [4 + 2] cycloaddition followed by ring expansion.

Synthesis of new kojic acid based unnatural α-amino acid derivatives.

An efficient method for the preparation of kojic acid based α-amino acid derivatives by alkylation of glycinate schiff base with bromokojic acids have been described. Using this method, mono as well as di alkylated kojic acid-amino acid conjugates have been prepared. This is the first synthesis of C-linked kojic acid-amino acid conjugate where kojic acid is directly linked to amino acid through a C-C bond.

Synthesis, in vitro anticancer and antimycobacterial evaluation of new 5-(2,5-dimethoxyphenyl)-1,3,4-thiadiazole-2-amino derivatives.

A series of 2,5-disubstituted-1,3,4-thiadiazole derivatives 5a-5l, 7a-7e and 9 have been synthesised and screened for in vitro antimycobacterial activity against Mycobacterium smegmatis MC-155. In addition these compounds have also been screened for cytotoxic activity against cancer cell lines HT-29, MDA-MB-231 by MTT colorimetric assay. The compounds are well characterized by spectral analysis viz. (1)H NMR, (13)C NMR, FT-IR, mass and HRMS. Screening results indicate that compounds 5g, 7a possess good antitubercular activity with MIC value 65.74 and 40.86, respectively, compounds 5g, 7a, 7b, 7d, 7e and 9 displayed promising cytotoxic activity against the cell lines tested. 5g and 7a stand out to be potent antimycobacterial and anticancer agents among the tested series. Further the title compounds were also tested on human normal cells HEK293T and are found to be safer with lesser cytotoxicity. It is interesting to observe that compound 5g has come out to be safer, potent anticancer and antimycobacterial agent.

Synthesis of Novel Diaziridinyl Quinone Isoxazole Hybrids and Evaluation of Their Anti-Cancer Activity as Potential Tubulin-Targeting Agents.

Two series of diaziridinyl quinone isoxazole derivatives were prepared and evaluated for their cytotoxic activity against MCF7, HeLa, BT549, A549 and HEK293 cell lines and interaction with tubulin. Compounds (6A-M: ) showed promising activity against all the 5 human cancer cell lines. Compounds 6A: , 6E: and 6 M: were potent [IC50 ranging between 2.21 µg to 2.87 µg] on ER-positive MCF7 cell line similar to the commercially available drug molecule Doxorubicin. The results from docking models are in consistent with the experimental values which demonstrated the favourable binding modes of compounds 6A-M: to the interface of α- and ß-tubulin dimer.

Design, synthesis and biological evaluation of diaziridinyl quinone isoxazole hybrids.

A series of novel diaziridinyl quinone isoxazole hybrids (9a-9j) were synthesized starting from 2, 5-dimethoxy acetophenone 1 via Claisen reaction, cyclisation, alkoxy carbonylation, hydrolysis, oxidation and aziridine insertion. All the compounds were screened for antimicrobial, anti-biofilm and cytotoxic activities. Among the screened compounds, the compound 9h showed good antibacterial and anti-biofilm activities with MIC value of 3.9, 3.9, 3.9 and 7.8 µg/mL, respectively, and IC50 values of 1.9, 2.5, 2.8 and 5.1 µM, respectively, against Staphylococcus aureus MTCC 96, S. aureus MLS-16 MTCC 2940, Bacillus subtilis MTCC 121 and Klebsiella planticola MTCC 530, and also exhibited potent antifungal activity against Candida albicans MTCC 227, C. albicans MTCC 854 and Candida krusei MTCC 3020 equipotent to standard miconazole (MIC value 7.8 µg/mL). All the synthesized compounds exhibited promising cytotoxicity against A549 and PC3 cell lines (IC50 values between 1 and 4 µM). Compounds 9b and 9j exhibited IC50 value of 0.5 µM which was similar to that of Mitomycin C against PC3 cell line.

Design and synthesis of novel isoxazole tethered quinone-amino Acid hybrids.

A new series of isoxazole tethered quinone-amino acid hybrids has been designed and synthesized involving 1,3-dipolar cycloaddition reaction followed by an oxidation reaction using cerium ammonium nitrate (CAN). Using this method, for the first time various isoxazole tethered quinone-phenyl alanine and quinone-alanine hybrids were synthesized from simple commercially available 4-bromobenzyl bromide, propargyl bromide, and 2,5-dimethoxybenzaldehyde in good yield.