The authors report a search in cold, quiescent and in hot core type interstellar mol. clouds for the small cyclic mol. oxiranecarbonitrile (C3H3NO), which was suggested as a precursor of important prebiotic mols. The authors detd. upper limits to the column d. and fractional abundance for the obsd. sources and find that, typically, the fractional abundance by no. relative to mol. H of C3H3NO is less than a few times 10-10. This limit is 1 to 2 orders of magnitude less than the measured abundance of such similarly complex species as CH3CH2CN and HCOOMe in well-studied hot cores. A no. of astrochem. discoveries were made, including the 1st detection of the species CH3CH2CN in the massive star-forming clouds G34.3+0.2 and W51M and the 1st astronomical detections of some 8 rotational transitions of CH3CH2CN, CH3CCH, and HCOOMe. The authors found 8 emission lines in the 89 GHz region and 18 in the 102 GHz region which the authors were unable to assign. [on SciFinder (R)]