Naphtho[2,3-b][1,4]-thiazine-5,10-diones and 3-substituted-1,4-dioxo-1,4-dihydronaphthalen-2-yl-thioalkanoate derivatives: Synthesis and biological ev

Bioorganic & Medicinal Chemistry Letters Volume 16, Issue 22, 15 Nov. 2006, Pages 5883-5887

doi:10.1016/j.bmcl.2006.08.060
Vishnu K. Tandon, Hardesh K. Maurya, Dharmendra B. Yadav, Ashutosh Tripathi, Manish Kumar, Praveen K. Shukla
A series of 3-substituted-1,4-dioxo-1,4-dihydronaphthalen-2-yl-thio-alkanoate derivatives 3–21 and naphtho[2,3-b][1,4]-thiazine-5,10-diones 24 were synthesized and evaluated for their antibacterial and antifungal activities. The structure–activity relationships of these compounds were studied and the results show that the compound 24a exhibited better antibacterial activity than Gentamycin in vitro against Staphylococcus aureus. In addition 24a also imparted marked antifungal activity in vitro against Cryptococcus neoformans, Sporothrix schenckii, and Trichophyton mentagraphytes when compared with Fluconazole. Compounds 15, 18, 19, and 21 also exhibited significant antibacterial activity in vitro against S. aureus.

Design, synthesis, and biological evaluation of 1,2,3-trisubstituted-1,4-dihydrobenzo[g]quinoxaline-5,10-diones and related compounds as antifungal ..

Bioorganic & Medicinal Chemistry       Volume 14, Issue 17, 1 September 2006, Pages 6120-6126 doi:10.1016/j.bmc.2006.04.029

Vishnu K. Tandon, Dharmendra B. Yadav, Hardesh K. Maurya, Ashok K. Chaturvedi and Praveen K. Shukla
A series of (S)-N-(3-chloro-1,4-naphthoquinon-2-yl)-α-amino acid ethyl esters 3 and 1,2,3-trisubstituted-1,4-dihydrobenzo[g]quinoxaline-5,10-diones 6–23 were synthesized and evaluated for antifungal and antibacterial activities. The structure–activity relationship of these compounds was studied and the results show that the compounds 3a and 3b exhibited in vitro antifungal activity against Candida albicans, Cryptococcus neoformans, and Sporothrix schenckii whereas compounds 12 and 22 showed in vitro antibacterial activity against Klebsiella pneumoniae and Escherichia coli.

Design, synthesis and biological evaluation of novel nitrogen and sulfur containing hetero-1,4-naphthoquinones as potent antifungal and antibacterial

European Journal of Medicinal Chemistry           Volume 44, Issue 8, August 2009, Pages 3130-3137 doi:10.1016/j.ejmech.2009.03.006

Vishnu K. Tandon,  Hardesh K. Maurya, Nripendra N. Mishra and Praveen K. Shukla
A series of 2-Arylamino-3-chloro-1,4-naphthoquinones (3), 2-Amino-3-arylsulfanyl-1,4-naphthoquinones (5), 2-Arylamino-3-arylsulfanyl-1,4-naphthoquinones (6), Dihydrobenzo[f]naphtho[2,3-b][1,4]thiazepine-6,11-diones (9) (via Pictet–Spengler cyclization), Isoindoline-1,3-dione derivatives of 1,4-naphthoquinone (13), 2,2′-(1,4-Dioxo-1,4-dihydronaphthalene-2,3-diyl)bis(methylene)dibenzonitrile (14), 13-Amino-12-substituted-6H-benzo[e]naphtho [2,3-b][1,4]diazepine-6,11(12H)-diones (15–16), 2-Chloro-3-arylsulfanyl-1,4-naphthoquinones (17–18) and 3-Methyl-6H-benzo[b]phenothiazine-6,11(12H)-dione (19) were synthesized and studied for their antifungal and antibacterial activities. The results indicate that compounds 3b, 5a and 5b have potent antifungal activity. Amongst the most promising antifungal compound 3b showed better antifungal activity than clinically prevalent antifungal drug Fluconazole (MIC50 = 2.0 μg/mL) against Sporothrix schenckii (MIC50 = 1.56 μg/mL), significant profile against Candida albicans (MIC50 = 1.56 μg/mL), Cryptococcus neoformans (MIC50 = 0.78 μg/mL) and Trichophyton mentagraphytes (MIC50 = 1.56 μg/mL) and same antifungal activity when compared with Amphotericin-B against C. neoformans (MIC50 = 0.78 μg/mL). Compounds 3b, 5a and 5b also showed promising antibacterial activity.

2,3-Disubstituted-1,4-naphthoquinones, 12H-benzo[b]phenothiazine-6,11-diones and related compounds: Synthesis and Biological evaluation as potential a

European Journal of Medicinal Chemistry            Volume 44, Issue 3, March 2009, Pages 1086-1092
doi:10.1016/j.ejmech.2008.06.025
Vishnu K. Tandon,  Hardesh K. Maurya, Ashutosh Tripathi, G.B. ShivaKeshava, Praveen K. Shukla, Pallavi Srivastava and Dulal Panda

A series of 2-chloro-3-arylsulfanyl-[1,4]naphthoquinones (2), 2,3-bis-arylsulfanyl-[1,4]naphthoquinones (3) and 12H-benzo[b]phenothiazine-6,11-diones and their analogs 6–8 were synthesized and evaluated for their antiproliferative activity against human cervical cancer (HeLa) cells. Compounds 3a and 3b were found to possess most potent antiproliferative and cell killing ability. Compounds 1–8 were also evaluated for antifungal activities. The structure–activity relationship of these compounds was studied and the results show that compound 2a (MIC50 = 1.56 μg/mL) exhibited in vitro potent antifungal activity compared to the clinically useful antifungal drug Fluconazole (MIC50 = 2.0 μg/mL) against Sporothrix. schenckii. Compound 2a (MIC50 = 1.56 μg/mL) also exhibited same antifungal activity compared to clinically useful drug Amphotericin-B (MIC50 = 1.56 μg/mL) against Trichophyton mentagraphytes.

Facile and Efficient Synthesis of 1,4-Benzodiazepines from 1,4-Naphthoquinones

Heterocycles, Volume 76, Issue 2 ( November, 1, 2008 ), Pages 1007-1010
DOI: 10.3987/COM-08-S(N)63

Vishnu K. Tandon and Hardesh K. Maurya
Concise intramolecular cyclization reaction of 2,3-diamino-1,4-dihydro-naphthalenediones 4 and 7 in anhydrous K2CO3 /Et3N and EtOH yielded novel 1,4-benzodiazepines 5 and 6 fused with 1,4-naphthoquinone nucleus.

Facile and Efficient Synthesis of Novel Oxazine, Oxazepine and Phenoxazine of Chromenones Fused with 1,4-Naphthoquinone

Heterocycles, Volume 77, Issue 1 ( January, 1, 2009 ), Pages 611-615         DOI: 10.3987/COM-08-S(F)30 Vishnu K. Tandon and Hardesh K. Maurya

A series of novel mono ethers 5, 7, diethers 6, 8, 9, oxazine 10, oxazepine 11 and phenoxazines 12 of chromenones fused with 1,4-naphthoquinone have been synthesized.

Nickel – Promoted Favorskii Type Rearrangement of Cyclic α-Bromoketones

Heterocycles, Volume 80, Issue 1 ( January, 1, 2010 ), Pages 593-600           DOI: 10.3987/COM-08-S(S)4

Vishnu K. Tandon, Anoop K. Awasthi, Kunwar A. Singh, Hardesh K. Maurya and Sanjay K. Gautam
Favorskii type rearrangement of cyclic α-bromo ketones 2 is promoted by NiCl2 in refluxing methanol, giving the rearranged carboxylic acid ester 3 in excellent yields. The reaction of 4-bromo-2,3,4,5-tetrahydronaphth [2,1-b]oxepin-5-one (5) and its regioisomer 8 with NiCl2 in MeOH resulted in Favorskii rearranged carboxylic acid esters 6 and 9 respectively.

An Expeditious Concise Synthesis of Benzo[b]pyrano[2,3-d]oxepines and Dibenzo[b,d]oxepines

Synlett 2009(18): 2992-2996                                    DOI: 10.1055/s-0029-1218006             

Vishnu K. Tandon, Hardesh K. Maurya, Balendu Kumar, Brijesh Kumar, Vishnu Ji Ram
An efficient concise synthesis of 4-methylthio-2-oxo-5,6-dihydro-2H-benzo[b]pyrano[2,3-d]oxepine-3-carbonitriles has been delineated through condensation-cyclization of 3,4-dihydro-2H-benzo[b]oxepin-5(2H)-ones and methyl 2-cyano-3,3-dimethylthioacrylate in DMF using powdered KOH as a base. A base-­induced reaction of 3,4-dihydro-2H-benzo[b]oxepin-5(2H)-ones and 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitrile in the presence of powdered KOH in DMF gave an isomeric mixture of (E)- and (Z)-2-(4-phenyl-5,6-dihydro-2H-benzo[b]pyrano[2,3-d]oxepin-2-ylidene)acetonitriles. However, the ring transformation of 6-aryl-4-(sec-amino)-2H-pyran-2-one-3-carbonitriles from 3,4-dihydro-2H-benzo[b]oxepin-5(2H)-ones under analogous reaction conditions exclusively gave 8-phenyl-10-(sec-amino)-6,7-dihydrodibenzo[b,d]oxepine-11-carbonitriles.