New spectroscopic data were obtained for the early-type binaries V337 Aql, V649 Cas, V382 Cyg, and V431 Pup. Their radial velocity curves are presented. These are the first such data for V337 Aql and V431 Pup. In the case of V382 Cyg, our data confirm previously obtained results. Especially for V649 Cas our radial velocity curve yields important new implications for the component masses: the detection of third body lines, which are blended with the lines of the primary component, solves the

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... lem of the unacceptably small masses formerly deduced for this binary; now we determine masses closer to the values expected for spectral type B 0. V431 Pup is an important object, because it is a new member of the small group of early-type eclipsing binaries with an evolved component. A published light curve of V337 Aql is solved by the MORO code, and system parameters are derived. The period of V649 Cas is found to be variable, and a more accurate period is calculated for V431 Pup. Article published by EDP Sciences and available at http://www.aanda.org or http://dx.