Effect of substituents on thermal behavior of some symmetric double schiff’s bases containing a cardo group

1083-1087Thermal behavior of symmetric double schiff’s bases containing cardo group has been studied by TGA and DSC techniques at 10°C/min in nitrogen atmosphere. DSC transitions, thermal stability and kinetic parameters are affected by nature and position of substituents. Schiff’s bases are thermally stable between 173-272°C and followed either a single step or two steps degradation (fractional or integral order). Different magnitudes of n, E and A suggested different degradation mechanisms. A large and negative magnitudes of “S* confirmed highly ordered transition state, while positive magnitudes of “S* confirmed less ordered transition state

A cleaner approach for reduction of some symmetric diimines using NaBH4

438-442Symmetric diimines have been reduced to their corresponding amines by means of NaBH4 using THF as a solvent at room temperature. The reaction time and yield are 3-4 hr and 77-93%, respectively. Reduction process is very effective, inexpensive and clean for the synthesis of symmetric diamines in good yield. The structures of the compounds are supported by FTIR, mass spectrometry, ¹H and ¹³C NMR spectral dat

Microwave assisted and classical synthesis of symmetric double Schiff bases of 1, 1’-bis (4-amino-3-methylphenyl) cyclohexane and their antimicrobial assay

43-47<span style="font-size:9.0pt;mso-bidi-font-family: " times="" new="" roman";color:black;mso-ansi-language:en-us;mso-bidi-font-weight:="" bold"="" lang="EN-US">Symmetric double Schiff bases have been synthesized by microwave assisted and classical facile condensation reaction of aromatic aldehydes and 1,1’-bis(4-amino-3-methylphenyl)cyclohexane. The structure of Schiff bases are supported by FTIR, UV, 1H<span style="font-size:9.0pt; mso-bidi-font-family:" times="" new="" roman";color:black;mso-ansi-language:en-us;="" mso-bidi-font-weight:bold"="" lang="EN-GB"> <span style="font-size:9.0pt; mso-bidi-font-family:" times="" new="" roman";color:black;mso-bidi-font-weight:bold"="" lang="EN-GB">NMR and MS techniques<span style="font-size:9.0pt;mso-bidi-font-family: " times="" new="" roman";color:black;mso-ansi-language:en-us;mso-bidi-font-weight:="" bold"="" lang="EN-US">. Microwave technique yielded improved reaction yields (88-96) and drastic reduction in reaction time (0.5-2.2 min). They possess mild to comparable antibacterial activity and mild antifungal activity as compared to chosen standard drugs. </span