Compounds and treatment methods with compounds exhibiting antiviral activity and/or inhibition of viral replication against viruses, particularly those belonging to the picornavirus-like supercluster, including coronavirus.

The invention provides heterocyclic compounds with quaternary centers and methods of preparing compounds. Methods include the method for the preparation of a compound of Formula (II): ##STR00001##
comprising treating a compound of Formula (I): ##STR00002##
with a transition metal catalyst and under alkylation conditions as valence and stability permit.

The invention provides processes for preparing intermediates useful for preparing compounds of the formula: ##STR00001##
or a tautomer or salt thereof, where R.sup.1-R.sup.5, a, b, X and P.sup.2, are as defined in the specification.

The invention provides processes for preparing intermediates useful for preparing compounds of the formula: ##STR00001##
or a tautomer or salt thereof, where R.sup.1-R.sup.5, a, b, X and P.sup.2, are as defined in the specification.

The invention provides processes for preparing intermediates useful for preparing compounds of the formula:

##STR00001##

or a tautomer or salt thereof, where R.sup.1-R.sup.5, a, b, X and P.sup.2, are as defined in the specification.

The invention provides processes for preparing intermediates useful for preparing compounds of the formula:

##STR00001##

or a tautomer or salt thereof, where R.sup.1-R.sup.5, a, b, X and P.sup.2, are as defined in the specification.

Disclosed are methods of extracting water from a composition of an organic liquid and water, using a polyol which causes a phase separation.

Disclosed are methods of extracting water from a composition of an organic liquid and water, using a polyol which causes a phase separation.

Process for purifying N-alkylpyrrolidones which due to a previous use comprise at least one of the impurities of the formula I or II ##STR00001##
where R is hydrogen or a C1-C20-alkyl group,
wherein a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80 C. not more than 20 minutes after addition of the basic compound and N-alkylpyrrolidone is distilled off from the mixture obtained.

Process for purifying N-alkylpyrrolidones which due to a previous use comprise at least one of the impurities of the formula I or II ##STR00001##
where R is hydrogen or a C1-C20-alkyl group,
wherein a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80 C. not more than 20 minutes after addition of the basic compound and N-alkylpyrrolidone is distilled off from the mixture obtained.