Mandava V. Basaveswara Rao

Synthesis of 2H-1,3-benzoxazin-4(3H)-one derivatives containing indole moiety: Their in vitro evaluation against PDE4B

A number of 2H-1,3-benzoxazin-4(3H)-one derivatives containing indole or benzofuran moieties were synthesized by using Pd/C-Cu mediated coupling-cyclization strategy as a key step. The o-iodoanilides or o-iodophenol were coupled with 3-{2-(prop-2-ynyloxy)ethyl}-2H-benzo[e][1,3]oxazin-4(3H)-one using 10%Pd/C-CuI-PPh3 as a catalyst system and Et3N as a base to give the target compounds. All the synthesized compounds were tested for their PDE4B inhibitory potential in vitro using a cell based cAMP reporter assay. Some of them showed fold increase of the cAMP level when tested at 30 μM. A representative compound showed encouraging PDE4B inhibitory properties that were supported by its docking results.

A concise stereoselective total synthesis of diplodialide C

An asymmetric total synthesis of diplodialide C has been achieved starting from commercially available homoallylic alcohol. Regioselective opening of the chiral epoxide, cross-metathesis reaction, and Yamaguchi macrolactonization were used as the key steps in this synthesis.Graphical Abstract

Stereoselective synthesis of (−)-tetrahydropyrenophorol

A simple and efficient synthesis of macrocyclic dilactone tetrahydropyrenophorol has been accomplished from inexpensive and commercially available starting materials. This concise synthesis utilizes regioselective ring opening of epoxide, asymmetric dihydroxylation, and Mitsunobu reaction for the construction of the macrolactone.Graphical abstract

An efficient and convenient protocol for the synthesis of tetracyclic isoindolo[1,2-a]quinazoline derivatives

A convenient and one-pot synthesis of tetracyclic isoindolo [1,2-a]quinazoline derivatives via Lewis acid mediated sequential C–N bond formation reactions is reported. This protocol provides a simple and rapid strategy for the synthesis of 12-benzylidene-10,12-dihydroisoindolo[1,2-b]quinazoline derivatives. However, a variety of tetracyclo indole fused quinazoline motifs were synthesized in good yields.

Catalysis by Amberlyst A-21: A Greener Approach to 4,5,6,7-Tetrahydro-1H-indazol-3(2H)-ones via Construction of Cyclohexanones

Abstract The 4,5,6,7-tetrahydro-1H-indazol-3(2H)-one derivatives have been synthesized in good yields via a two-step method in a single pot. The initial step involved the construction of cyclohexanone ring from aromatic aldehydes and β-ketoester in i-PrOH using an inexpensive and reusable catalyst (i.e., Amberlyst A-21) under mild reaction conditions. The utility of this catalyst has been demonstrated in synthesizing a range of cyclohexanone derivatives. The catalyst can be recovered and recycled, which makes this procedure simple, convenient, economically viable, and environmental friendly. [Supplementary materials are available for this article. Go to the publishers online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] GRAPHICAL ABSTRACT

Ultrasound Assisted Synthesis of 3,4-Diyne Substituted Isocoumarin Derivatives: Identification of Potential Cytotoxic Agents

BACKGROUND The 3,4-diyne substituted isocoumarins have been designed, synthesized and explored as potential anti-proliferative agents. METHOD Ultrasound assisted synthesis of these compounds was carried out by using a three-step method involving (i) Pd/C-Cu catalyzed cross-coupling between the methyl 2-iodobenzoate and buta- 1,3-diynylbenzene followed by (ii) I2-mediated electrophilic cyclization of the resultant 2-(alk-1- ynyl)benzoate ester and (iii) subsequent alkynylation of 4-iodo-3-(phenylethynyl)-isocoumarin under Pd/C-Cu catalysis. CONCLUSION The synthesized compounds showed promising growth inhibition when tested against MDA-MB 231 and K562 cancer cell lines.

Ultrasound Assisted Synthesis of Quinoline Derivatives in the Presence of SnCl2·2H2O as a Precatalyst in Water: Evaluation of their Antibacterial Activities

BACKGROUND SnCl2·2H2O has been used as a convenient precatalyst for the one-pot and rapid synthesis of 2-substituted quinolines under ultrasound irradiation in water. The reaction involved a 3-component reaction of aniline, aldehydes, and ethyl 3,3-diethoxypropionate in the presence of aerial oxygen to give the desired products in good yields. CONCLUSION Several of these compounds showed antibacterial activities when tested against gram-positive and gram-negative species. One compound i.e. 4b showed promising activities across both the species.

Ultrasound Assisted One-pot and Sequential Synthesis of 3-methyleneisoindolin- 1-ones and their in vitro Evaluation

BACKGROUND 3-Methyleneisoindolin-1-one derivatives containing a pyridin-2-ylmethyl substituent on their ring nitrogen were designed as potential bioactive agents. A one-pot synthesis of these compounds was achieved via sequential C-C coupling, followed by C-Si bond cleavage and subsequent tandem C-C/C-N bond forming reaction under ultrasound irradiation. METHOD The methodology involved coupling of (trimethylsilyl)acetylene with iodoarenes in the presence of 10% Pd/C-CuI-PPh3-Et3N in MeOH followed by treating the reaction mixture with K2CO3 in aqueous MeOH, and finally coupling with 2-iodo-N-(pyridin-2-ylmethyl)benzamide. The in vitro evaluation of these compounds was performed to identify some initial hit molecules one of which showed dose dependent inhibition of PDE4B.