  The observation of oxygen (O)- and nitrogen (N)-bearing molecules gives an
idea about the complex prebiotic chemistry in the interstellar medium (ISM). In
this article, we present the identification of the rotational emission lines of
N-bearing molecules ethyl cyanide (C$_{2}$H$_{5}$CN), cyanoacetylene
(HC$_{3}$N), and O-bearing molecules methyl formate (CH$_{3}$OCHO) towards
high-mass protostar IRAS 18089$-$1732 using the Atacama Compact Array (ACA). We
also detected the emission lines of both N- and O-bearing molecule formamide
(NH$_{2}$CHO) in the envelope of IRAS 18089$-$1732. We have detected the $v$ =
0 and 1 states rotational emission lines of CH$_{3}$OCHO. We also detected the
two vibrationally excited states of HC$_{3}$N ($v$7 = 1 and $v$7 = 2). The
estimated fractional abundances of C$_{2}$H$_{5}$CN, HC$_{3}$N ($v$7 = 1),
HC$_{3}$N ($v$7 = 2), and NH$_{2}$CHO towards the IRAS 18089$-$1732 are
(1.40$\pm$0.5)$\times$10$^{-10}$, (7.5$\pm$0.7)$\times$10$^{-11}$,
(3.1$\pm$0.4)$\times$10$^{-11}$, and (6.25$\pm$0.82)$\times$10$^{-11}$.
Similarly, the estimated fractional abundances of CH$_{3}$OCHO ($v$ = 0) and
CH$_{3}$OCHO ($v$ = 1) are (1.90$\pm$0.9)$\times$10$^{-9}$ and
(8.90$\pm$0.8)$\times$10$^{-10}$, respectively. We also created the integrated
emission maps of the detected molecules, and the observed molecules may have
originated from the extended envelope of the protostar. We show that
C$_{2}$H$_{5}$CN and HC$_{3}$N are most probably formed via the subsequential
hydrogenation of the CH$_{2}$CHCN and the reaction between C$_{2}$H$_{2}$ and
CN on the grain surface of IRAS 18089$-$1732. We found that NH$_{2}$CHO is
probably produced due to the reaction between NH$_{2}$ and H$_{2}$CO in the gas
phase. Similarly, CH$_{3}$OCHO is possibly created via the reaction between
radical CH$_{3}$O and radical HCO on the grain surface of IRAS 18089$-$1732.
