Oxidation of 1,3-pentadiene on a mixed V/Mo/P/Ti/Al oxide catalyst at 315-degrees-C gave maleic anhydride as the single major product at ca. 99% conversion, but many products at 20-30% conversion. Of these, 43 have been identified and put into perspective to a reaction network, which describes the reaction paths from 1,3-pentadiene to maleic anhydride. Oxidations of the supposed intermediates 3-pentene-2-one, 2-methylfurane and 5-methyl-2(3 H)-furanone were in support of the proposed raction paths, which proceed via 2-methylfurane as a key intermediate.