Context. Open clusters are ideal test particles for studying the chemical evolution of the Galactic disc. However, the number and accuracy of existing high-resolution abundance determinations, not only of [Fe/H], but also of other key elements, remains largely insufficient. Aims: We attempt to increase the number of Galactic open clusters that have high quality abundance determinations, and to gather all the literature determinations published so far. Methods: Using high-resolution (R ~ 30 000), high-quality (S/N ≥ 60 per pixel), we obtained spectra for twelve stars in four open clusters with the fibre spectrograph FOCES, at the 2.2 Calar Alto Telescope in Spain. We employ a classical equivalent-width analysis to obtain accurate abundances of sixteen elements: Al, Ba, Ca, Co, Cr, Fe, La, Mg, Na, Nd, Ni, Sc, Si, Ti, V, and Y. We derived oxygen abundances by means of spectral synthesis of the 6300 Å forbidden line. Results: We provide the first determination of abundance ratios other than Fe for NGC 752 giants, and ratios in agreement with the literature for the Hyades, Praesepe, and Be 32. We use a compilation of literature data to study Galactic trends of [Fe/H] and [α/Fe] with Galactocentric radius, age, and height above the Galactic plane. We find no significant trends, but some indication for a flattening of [Fe/H] at large Rgc, and for younger ages in the inner disc. We also detect a possible decrease in [Fe/H] with |z| in the outer disc, and a weak increase in [α/Fe] with Rgc. Based on observations collected with the fiber spectrograph FOCES at the 2.2 m Calar Alto Telescope. Also based on data from 2MASS survey and the WEBDA, VALD, NIST, and GEISA online database.Table 12 is available in electronic form at http://www.aanda.orgFull Table 5 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/535/A30