Manas Jyoti Sarma

Rapid and Total Bromination of Aromatic Compounds Using TsNBr2 Without Any Catalyst

Abstract N,N-Dibromo-p-toluenesulfonamide (TsNBr2) has been found to be a new reagent for bromination of aromatic compounds. The reaction is extremely fast and goes into completion instantaneously at ambient temperature to produce exclusively the corresponding polybrominated product. This procedure is applicable to various phenols, anisole, and anilines to give corresponding polybrominated compound as a single product in excellent yield. GRAPHICAL ABSTRACT

Unexpected C-C bond cleavage of α-nitroketone in the presence of TsNBr2: A new pathway for C-N bond formation

ABSTRACT A new catalyst-free protocol for C-N bond formation via the cleavage of α-nitroketone has been developed. When α -nitroketones are treated with TsNBr2 in the presence of potassium carbonate, unexpected cleavage of C(O)-CHNO2 bond of α -nitroketone was observed followed by the formation of corresponding amide. Various nitroketones could be converted to corresponding amide using this procedure. GRAPHICAL ABSTRACT

Surfactant Dependent pH Controlled “off-on”, “off-on-off” and “on-off” Fluorescent Switches Exhibited by N-Benzylidenenaphthalen-1-Amine

N-benzylidenenaphthalen-1-amine (L) acts as pH dependent “off-on”, “off-on-off” and “on-off” fluorescent switch in 1:1 (v/v) CH3CN:H2O depending on the presence of anionic sodiumdocdecyl sulphate (SDS), neutral triton X-100 (TX-100) and cationic cetyltrimethylammonium bromide (CTAB) surfactants respectively. DFT calculation shows the possibility of formation of L.H+ due to protonation at immine N and L.OH− due to introduction of OH− group at immine C. The relative stability of these two cationic and anionic species depends on the charge environment provided by surfactants. This influences the photoinduced electron transfer (PET) processes involved and results in different switch behaviour.

Metal-free synthesis of secondary amines by the reaction of tosyl triazene and aryl boronic acid

ABSTRACT A metal free noncatalytic amination process has been developed for the synthesis of N-substituted aniline using a new amine source. The amine source p-toluene sulfonyl triazene (PhN˭NNHTs) has been prepared by treating aryldiazonium salt with p-tosylamide. Various unsymmetrical amines could be synthesized by treating this reagent and boronic acid in toluene at 110 °C in the presence of DBU and 4 Å molecular sieve. A large variety of N-substituted aniline could be synthesized with moderate yield. GRAPHICAL ABSTRACT