Provided herein are compounds of Formula (I), their pharmaceutically acceptable salts, and their pharmaceutical compositions:

##STR00001##

wherein R.sup.1, R.sup.2, R.sup.3a, R.sup.3b, R.sup.4, R.sup.5, and A are defined in the present disclosure. The compounds are potent inhibitors of the main protease (M.sup.pro) of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2), and they are useful in treating or preventing COVID-19 in a subject.

Disclosed are compounds of Formulas (I), (II), (III), (IV), and (V): ##STR00001##
and/or a salt thereof, wherein R.sub.1 is —OH or —OP(O)(OH).sub.2, and X.sub.1, X.sub.2, X.sub.3, R.sub.2, R.sub.2a, R.sub.a, R.sub.b, and R.sub.c are defined herein. Also disclosed are methods of using such compounds as selective agonists for G protein-coupled receptor S1P.sub.1, and pharmaceutical compositions comprising such compounds. These compounds are useful in treating, preventing, or slowing the progression of diseases or disorders in a variety of therapeutic areas, such as autoimmune diseases and vascular disease.

A pharmaceutical containing a compound having an agonist activity for LPA3 as an active ingredient, wherein the compound is of formula (IY):

##STR00001##

wherein all symbols represent the same meaning as described in the specification, and which is useful as a preventive and/or therapeutic agent for, e.g., essential thrombocythemia or reactive thrombocytosis.

A pharmaceutical containing a compound having an agonist activity for LPA3 as an active ingredient, wherein the compound is of formula (IY):

##STR00001##

wherein all symbols represent the same meaning as described in the specification, and which is useful as a preventive and/or therapeutic agent for, e.g., essential thrombocythemia or reactive thrombocytosis.

The present disclosure is directed to chemical compounds and to the use of such compounds in the treatment of diseases associated with a serotonin 5-HT.sub.2 receptor.

##STR00001##

This disclosure relates to modulators of liver receptor homologue 1 (LRH-1) and methods of managing disease and conditions related thereto. In certain embodiments, modulators are derivatives of hexahydropentalene. In certain embodiments, this disclosure relates to methods of treating or preventing cancer, diabetes, or cardiovascular disease by administering an effective amount of a hexahydropentalene derivative disclosed herein.

This disclosure relates to modulators of liver receptor homologue 1 (LRH-1) and methods of managing disease and conditions related thereto. In certain embodiments, modulators are derivatives of hexahydropentalene. In certain embodiments, this disclosure relates to methods of treating or preventing cancer, diabetes, or cardiovascular disease by administering an effective amount of a hexahydropentalene derivative disclosed herein.

A new set of bench-stable fluoroalkylphosphines that directly convert C—H bonds in pyridine building blocks, drug-like fragments, and pharmaceuticals, into fluoroalkyl derivatives. No pre-installed functional groups or directing motifs are required. The reaction tolerates a variety of sterically and electronically distinct pyridines and is exclusively selective for the 4-position in most cases. The reaction proceeds via initial phosphonium salt formation followed by sp.sup.2-sp.sup.3 phosphorus ligand-coupling, an underdeveloped manifold for C—C bond formation.

A new set of bench-stable fluoroalkylphosphines that directly convert C—H bonds in pyridine building blocks, drug-like fragments, and pharmaceuticals, into fluoroalkyl derivatives. No pre-installed functional groups or directing motifs are required. The reaction tolerates a variety of sterically and electronically distinct pyridines and is exclusively selective for the 4-position in most cases. The reaction proceeds via initial phosphonium salt formation followed by sp.sup.2-sp.sup.3 phosphorus ligand-coupling, an underdeveloped manifold for C—C bond formation.

The present application relates to psilocin derivatives of Formula (I), to processes for their preparation, to compositions comprising them and to their use in activation of a serotonin receptor in a cell, as well as to treating diseases, disorders or conditions by activation of a serotonin receptor in a cell. ##STR00001##