  We report on the discovery of methyl acetate, CH3COOCH3, through the
detection of a large number of rotational lines from each one of the spin
states of the molecule: AA species (A1 or A2), EA species (E1), AE species
(E2), EE species (E3 or E4). We also report the detection, for the first time
in space, of the $gauche$ conformer of ethyl formate, CH3CH2OCOH, in the same
source. The trans conformer is also detected for the first time outside the
galactic center source SgrB2. From the derived velocity of the emission of
methyl acetate we conclude that it arises mainly from the compact ridge region
with a total column density of (4.2+-0.5)E15 cm(-2). The derived rotational
temperature is 150 K. The column density for each conformer of ethyl formate,
trans and gauche, is (4.5+-1.0)E14 cm(-2). Their abundance ratio indicates a
kinetic temperature of 135 K for the emitting gas and suggests that gas phase
reactions could participate efficiently in the formation of both conformers in
addition to cold ice mantle reactions on the surface of dust grains.
