This invention generally relates to pyrazolo pyrimidine derivatives useful as inhibitors of short chain dehydrogenase/reductase (SDR) family of NAD(P)(H) dependent oxido-reductases. The invention further relates to pharmaceutical compositions and methods of preventing or treating disease with 1H-Pyrrolo[2.3-d]pyrimidine derivatives. More specifically, the invention relates to a 1H-Pyrrolo[2.3-d]pyrimidine which is a compound of Formula I or II: ##STR00001## or a pharmaceutically-acceptable salt or prodrug thereof; wherein: Y is N or CR.sub.5; Z is NR.sub.3R.sub.4, halo, H, OH, alkyl, alkyloxy, or haloalkyl; and R.sub.1a is indolyl, thiazolyl, benzyl, biphenylyl, thiophenyl, pyrrolyl, or phenyl, wherein said phenyl is substituted with at least one of OH, --NR.sub.3R.sub.4, --C(.dbd.O)NR.sub.6R.sub.7, --CN, NO.sub.2--C(.dbd.O)OH, --C(.dbd.O)O-alkyl, (C.sub.1-C.sub.4)alkyl, halo, haloalkyl or haloaryl; and wherein said indolyl, thiazolyl, benzyl, biphenylyl, thiophenyl, or pyrrolyl is optionally substituted with OH, --NR.sub.3R.sub.4, --C(.dbd.O)NR.sub.6R.sub.7, --CN, NO.sub.2, --C(.dbd.O)O--R.sub.3, (C.sub.1-C.sub.4)alkyl, halo, haloalkyl or haloaryl.