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The TOPG\"ot project studies a sample of 86 high-mass star-forming regions indifferent evolutionary stages from starless cores to ultra compact HII regions.The aim of the survey is to analyze different molecular species in astatistically significant sample to study the chemical evolution in high-massstar-forming regions, and identify chemical tracers of the different phases.The sources have been observed with the IRAM 30m telescope in differentspectral windows at 1, 2, and 3 mm. In this first paper, we present the sampleand analyze the spectral energy distributions (SEDs) of the TOPG\"ot sources toderive physical parameters. We use the MADCUBA software to analyze the emissionof methyl cyanide (CH$_3$CN), a well-known tracer of high-mass star formation.The emission of the $\rm{CH_3CN(5_{K}-4_{K})}$ K-transitions has been detectedtowards 73 sources (85% of the sample), with 12 non-detections and one sourcenot observed in the frequency range of $\rm{CH_3CN(5_{K}-4_{K})}$. The emissionof CH$_3$CN has been detected towards all evolutionary stages, with the meanabundances showing a clear increase of an order of magnitude from high-massstarless-cores to later evolutionary stages. We found a conservative abundanceupper limit for high-mass starless cores of $X_{\rm CH_3CN}<4.0\times10^{-11}$,and a range in abundance of $4.0\times10^{-11}<X_{\rmCH_3CN}<7.0\times10^{-11}$ for those sources that are likely high-mass starlesscores or very early high-mass protostellar objects. In fact, in this range ofabundance we have identified five sources previously not classified as being ina very early evolutionary stage. The abundance of $\rm{CH_3CN}$ can thus beused to identify high-mass star-forming regions in early phases ofstar-formation.

The TOPG\"ot high-mass star-forming sample. I. Methyl cyanide emission as tracer of early phases of star formation