2400 series 2 elemental chns analyser

A CEM Discover microwave synthesizer (Model No: 908010) operating at 180/264 V and 50/60 Hz with microwave power maximum level of 300 W and microwave frequency of 2455 MHz was employed for the microwave-assisted experiments. Nuclear Magnetic Resonance (¹H, ¹³C two-dimensional COSY NMR) spectra were recorded on 300 MHz or 400 MHz spectrometers (Bruker) in CDCl₃ and DMSO-d₆ using TMS as an internal standard. Chemical shifts are reported in parts per million (δ), coupling constants (J values) are reported in Hertz (Hz) and spin multiplicities are indicated by the following symbols: s (singlet), d (doublet), t (triplet), m (multiplet). ¹³C NMR spectra were routinely run with broadband decoupling. Pre coated silica gel on aluminium plates (Merck) were used for TLC analysis with a mixture of petroleum ether (60–80 °C) and ethyl acetate as the eluent. Electrospray ionization (ESI) mass spectra were obtained on an LCQ Fleet mass spectrometer, Thermo Fisher Instruments Limited, US and an Agilent mass spectrometer. Infrared spectra were recorded on a Shimadzu FTIR instrument (KBr pellet). Elemental analyses were performed on a Perkin Elmer 2400 Series II Elemental CHNS analyser. The NH signal, being very broad, is not noticed in many ¹H NMR spectra.

General Methods. Melting points were measured in KRUSS melting point meter using open capillary tubes and are uncorrected. ¹H and ¹³C NMR spectra were recorded on a Bruker 300 MHz instrument in DMSO using TMS as internal standard. Standard Bruker software was used throughout. Chemical shifts are given in parts per million (δ-scale) and the coupling constants are given in Hertz. IR spectra were recorded in a Perkin Elmer system 2000 FT IR instrument (KBr). Elemental analyses were performed on a Perkin Elmer 2400 Series II Elemental CHNS analyser. Mass spectra were recorded in Agilent technologies 7820A GC-MS system.

The melting points were measured using open capillary tubes and are uncorrected. ¹H, ¹³C and 2D NMR spectra were recorded on a JEOL 400 MHz instrument. Elemental analyses were carried out on a Perkin Elmer 2400 Series II Elemental CHNS analyser. Mass spectra were performed on JEOL-DX303 HF mass spectrometer.