This paper proposes a Software Defined Network (SDN) architecture for GeoBroadcast in VANETs. We have implemented a component to automatically manage the geographical location of Road Side Units (RSUs), which are used as a basis for our GeoBroadcast routing. GeoBroadcast in a vehicular network supports periodic broadcast messages from a source vehicle to the destination vehicles that are located in a specific geographical region. In existing Intelligent Transport Systems (ITS), the GeoBroadcast mechanism can be implemented using traditional IP networking. Typically, every periodic warning messages received at nearest RSU from the source must be routed to the control center in ITS, where it is redirected to every other RSUs, that are located in the destination geographical region for broadcasting. As a result, huge overhead in the control center is produced and higher network bandwidth is consumed. However, in our SDN based GeoBroadcast mechanism, the first warning message received by the source RSU is sent to the SDN controller as a packet-in message. The SDN controller will decode the packet-in message and use topological and geographical information to set up the routing paths to the destination RSUs, by installing appropriate flow entries on the corresponding RSUs and intermediate switches, for the following periodic warning messages that are to be broadcasted. As per our simulation with OpenNet a significant reduction by 84% in controller overhead, 60% in network bandwidth consumption, and 81% in latency are achieved.

One-pot oxidations of substituted 1-keto-1,2,3,4-tetrahydrocarbazoles (1) to carbazole-1,4-quinones (2) are efficiently carried out by CAN-SiO 2 -mediated reaction. This generalized protocol was successfully extended to the synthesis of two naturally occurring carbazoloquinones: murrayaquinone A (2b) and koeniginequinone A (2g). A plausible mechanism for this novel reaction involves formation of a 9-hydroxy-2,3,4,9-tetrahydro-1H-carbazole-1-one followed by rearrangement to 1-hydroxycarbazole derivatives, which are further oxidized by cerium (IV) to carbazoloquinones.

The structure and dynamics of water under confinement differ drastically from its bulk behavior and show a considerable degree of inhomogeneity due to disruption in its hydrogen bonding (H-bonding) network. We attempt to probe such a microheterogeneous environment of reverse micelles (RMs) as well as binary mixtures of acetonitrile−water and ethanol−water by a H-bond sensitive probe 5-methoxy-1-keto-1,2,3,4-tetrahydro carbazole (MTC). Photophysical properties (quantum yield, lifetime, λ max ) of MTC in the excited states are found to be extremely sensitive to the changes in the H-bonding of its immediate local environment. We observe huge Stoke's shifts in the λ max em of MTC with variation in the solvent environment, as we increase the polarity inside the nanopool of RMs and the mole fractions of water in the binary mixtures. We are able to effectively sense the subtle changes in the H-bonding network inside RMs with an increase in w 0 and the formation of self-aggregated microclusters inside the binary mixtures, by measuring the photophysical variations in steady state and time-resolved fluorescence of MTC. An iso-emissive point in the time-resolved area normalized spectra of MTC inside RMs suggests the presence of two distinct emissive species of MTC, (a) MTC* and (b) Hbonded MTC, h-MTC*, which are expected to be predominant in nonaqueous and aqueous media, respectively. The variations in the nature and type of the H-bonding in such self-assemblies and clusters with changes in aqueous environment are very well characterized by the photophysics of two isomers of MTC.

A concise total synthesis of carbazomycin G has been completed in five steps. Cerium(IV) ammonium nitrate (CAN)–SiO2‐mediated oxidation of 2‐methyl‐2,3,4,9‐tetrahydro‐1H‐ carbazol‐1‐one afforded a carbazole‐1,4‐quinone derivative, 2‐methyl‐1H‐carbazole‐1,4(9H)‐dione, the synthetic precusor, which on, which, on Thiele acetylation under newly developed HBF4 catalysis conditions, yielded 4‐hydroxy‐2‐methyl‐9H‐carbazole‐1,3‐diyl diacetate. Finally, CAN‐SiO2‐mediated oxidative hydrolysis of the acetylation product and O‐methylation using a stoichiometric amount of diazomethane and subsequent regioselective nucleophilic addition of methyllithium led to carbazomycin G.

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A novel and efficient methodology for the synthesis of carbazoles from 1-keto-1,2,3,4-tetrahydrocarbazoles via the corresponding tosylsulfonhydrazones by a one-pot tandem reduction-oxidation protocol using a combination of NaBH 4 and Pd-C on MgSO 4 Á7H 2 O, a solid support, under microwave is developed. The reaction is successfully extended toward the synthesis of several naturally occurring carbazole alkaloids, namely 3-methylcarbazole, glycozoline, clausenalene, glycozolicine, murrayafoline A, and deoxycarbazomycin B, a carbazole derivative that is known to have a promising antimicrobial activity.

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